Neuromodulation Of Cerebral Blood Flow

After the demonstration that spinal cord stimulation (SCS) can improve peripheral blood flow, Hosobuchi in 1986 first studied the effect of SCS on cerebral blood flow (CBF) in human beings. The group found that SCS could produce either an increase of CBF, a reduction, or no effect at all. A reduction of CBF is very rare and occurs when electrodes are place in a more caudal location, while cervical stimulation produces, more frequently, an increase in CBF (61% of cervical stimulations). The effect of SCS on CBF in rabbits suggests that a reversible functional sympathectomy occurs during SCS.
Neuromodulation; Jul2003, Vol. 6 Issue 3, p192-192, 1p

Visocchi, Massimiliano¹
Meglio, Mario¹

Sympathethetic influence on Cerebral Blood Volume following excsion of the superior cervical ganglia

Shortly after operation there is a leakage of the noradrenaline transmitter from the degenerating nerve terminals with and accompanying activation of the vascular receptor (the CVB was foudn to be reduced by 28%). When the transmitter has disappeared from the degenerating terminals, the neural influence of the vessels is abolished (the blood volume was increased by 34% compared to unoperated controls). About 2 weeks later, a pronounced denervation supersensitivity of the vascular receptors to circulating catecholamines develops (the CVB became nromal or even subnormal).
Another circumstance giving the impression of inconsistent results after denervation is that a difference in the effects of pre- and postganglionic operation is usually not fully considered.
Cellular and Molecular Life Sciences
Volume 28, Number 7 / July, 1972

bilateral ganglionectomy resulted in minor decreases in the cerebrovascular contents of ACh

The effects of uni- or bilateral surgical ablation of the SPG, a putative origin of the cholinergic cerebrovascular innervation, were investigated on these two specific cholinergic markers at various postoperative times. ChAT activity and ACh levels were enriched in the cerebral as compared to the peripheral arteries. Among the cerebrovascular tissues tested, ACh levels were particularly high in the circle of Willis and the vertebrobasilar segments and, to a lesser extent, in the middle cerebral artery. Lower levels were found in the small pial vessels and choroid plexus. Overall, ChAT activity measured in different arterial beds paralleled the distribution of ACh. Following uni- or bilateral removal of the SPG, slight reductions were observed in ChAT activity in rostral cerebral arteries and pial vessels overlying the frontal cortex. Similarly, bilateral ganglionectomy resulted in minor decreases in the cerebrovascular contents of ACh in these same vascular segments.
J Cereb Blood Flow Metab. 1991 Mar;11(2):253-60.

lactic acidosis, complication of thoracoscopic sympathectomy

We report a case of severe lactic acidosis in a patient undergoing thoracoscopic sympathectomy under general anesthesia who received repeated albuterol.
Lactic acidosis can occur in two different clinically distinguishable categories. The first (type A) occurs when oxygen delivery to the tissues is compromised. The second (type B) occurs when either lactate production is increased or lactate removal is decreased without obvious oxygen delivery problems. ^7,8
β-2 Receptor activation produces excess glycogenolysis and lipolysis. ¹⁰ Increased glycogenolysis eventually leads to increased concentrations of pyruvate. Pyruvate is converted to acetyl CoA, which enters the citric acid cycle. If pyruvate does not enter this aerobic pathway, it is converted to lactate instead, thereby potentially causing lactic acidosis.
journals.lww.com › Home › August 2003 - Volume 99 - Issue 2

Sympathectomy limits blood flow to a vital organ like the brain

1. Acta Physiol Scand. 2000 Sep;170(1):33-8.

Middle cerebral artery blood velocity during exercise with beta-1 adrenergic and unilateral stellate ganglion blockade in humans.

Ide K, Boushel R, Sørensen HM, Fernandes A, Cai Y, Pott F, Secher NH.

Department of Anaesthesia, The Copenhagen Muscle Research Centre, University of Copenhagen, Rigshospitalet, Denmark.

A reduced ability to increase cardiac output (CO) during exercise limits blood flow by vasoconstriction even in active skeletal muscle. Such a flow limitation may also take place in the brain as an increase in the transcranial Doppler determined middle cerebral artery blood velocity (MCA V(mean)) is attenuated during cycling with beta-1 adrenergic blockade and in patients with heart insufficiency. We studied whether sympathetic blockade at the level of the neck (0.1% lidocaine; 8 mL; n=8) affects the attenuated exercise - MCA V(mean following cardio-selective beta-1 adrenergic blockade (0.15 mg kg(-1) metoprolol
i.v.) during cycling. Cardiac output determined by indocyanine green dye dilution, heart rate (HR), mean arterial pressure (MAP) and MCA V(mean) were obtained during moderate intensity cycling before and after pharmacological intervention. During control cycling the right and left MCA V(mean) increased to the same extent (11.4 1.9 vs. 11.1 1.9 cm s(-1)). With the
pharmacological intervention the exercise CO (10 1 vs. 12 1 L min(-1); n=5), HR (115 4 vs. 134 4 beats min(-1)) and delta MCA V(mean) (8.7 2.2 vs. 11.4 1.9 cm s(-1) were reduced, and MAP was increased (100 5 vs. 86 2 mmHg; P < 0.05).

However, sympathetic blockade at the level of the neck eliminated the beta-1 blockade induced attenuation in delta MCA V(mean) (10.2 2.5 cm s(-1)). These results indicate that a reduced ability to increase CO during exercise limits blood flow to a vital organ like the brain and that this flow limitation is likely to be by way of the sympathetic nervous system.

PMID: 10971220 [PubMed - indexed for MEDLINE]

Long-Term Denervation of Vascular Smooth Muscle Causes Not Only Functional but Structural Change

Rosemary D. Bevan, Hiromichi Tsuru

Department of Pharmacology, School of Medicine, University of California, Los Angeles, Calif.

Address of Corresponding Author

Blood Vessels 1979;16:109-112 (DOI: 10.1159/000158197)

Spinal cord infarction occurring during thoraco-lumbar sympathectomy

Spinal cord infarction, because of interference with an important radicular tributary, is a rare complication of thoraco-lumbar sympathectomy.
In a brief survey of the literature we found only 12 previously recorded cases in which this complication
was presumed to have occurred.
J. Neurol. Neurosurg. Psychiat., 1963, 26, 418

profound decrease of arterial oxygen partial pressure during sympathectomy

Left-lung ventilation and right-chest operation caused profound decrease of arterial oxygen partial pressure (PaO2), compared with two-lung ventilation before surgery (70.7%, P > 0.0003) and compared with PaO2 at two-lung ventilation during and after surgery (decrease of 80.1% and 75.3%, respectively; P > 0.001 and < 0.005, respectively). Right-lung ventilation and left-chest operation did not cause hypoxemia.

Pulse oximetry and repeated blood gas measurements are needed during endoscopic transthoracic sympathectomy in order to detect and treat hypoxemic events, which may jeopardize the patient's life.
Journal of Cardiothoracic and Vascular Anesthesia
Volume 10, Issue 2, February 1996, Pages 207-209

hypoxic pulmonary vasoconstriction may be impaired after Sympathectomy

It is well known that hypoxic pulmonary vasoconstriction(HPV) plays an important role to protect hypoxemia during the atelectasis induced by one-lung ventilation. Thoracic sympathectomy may have effects on pulmonary vasculature(HPV) and hemodynamics during one-lung anesthesia.

Mean arterial blood pressure was decreased from 81.9+/-2.89 to 73.2+/-2.49 mmHg after thoracic sympathectomy and heart rate was decreased from 104.4+/-3.12 to 88.2+/-2.31beats/min. Arterial oxygen tension was decressed from 570.5+/-17.9 to 521.4+/-23.2mmHg after position change, and decreased to 271.1+/-28.1 mmHg under one-lung ventilation, and finally decreased to 217.0+/-18.3 mmHg after thoracic sympathectomy. With the above results, we can conclude that patients for TES should be carefully observed during and after the procedure, and hypoxic pulmonary vasoconstriction may be impaired after TES.
Korean J Anesthesiol. 1993 Aug;26(4):695-699.

sympathectomy will blunt the normal tachycardic response to hypovolemia

Spinal or epidural analgesia may cause a sympathectomy that will blunt the normal tachycardic response to hypovolemia.
OBSTETRIC ANAESTHESIA OUR WAY
Royal Women's Hospital Melbourne
Author: Dr Philip Popham

PATHOPHYSIOLOGY OF ONE-LUNG VENTILATION

In estimating the degree of shunt that is created by one-lung ventilation when it is performed in the lateral decubitus position, on average, 40% of cardiac output perfuses the nondependent lung and the remaining 60% perfuses the dependent lung (Fig. 1).¹⁵ Mechanisms that tend to decrease the percent of cardiac output perfusing the nondependent, nonventilated lung are passive (e.g., mechanical-like gravity, surgical manipulation, amount of pre-existing lung disease) or active (e.g., hypoxic pulmonary vasoconstriction).¹⁵ The normal response of the pulmonary vasculature to atelectasis is an increase in pulmonary vascular resistance (in the atelectatic lung), and the increase in atelectatic lung resistance is almost entirely caused by hypoxic pulmonary vasoconstriction. Hypoxic pulmonary vasoconstriction is a protective reflex mechanism that diverts blood flow away from the atelectatic lung. With an intact hypoxic pulmonary vasoconstriction response, the transpulmonary shunt through the nondependent lung decreases to approximately 23% of the cardiac output (see Fig. 1).
Anesthesiology Clinics of North America
Volume 19, Issue 3, 1 September 2001, Pages 435-453

Surgical Upper Thoracic Sympathectomy Reduces Arterial Oxygenation During One-Lung Ventilation

Journal of Cardiothoracic and Vascular Anesthesia
Volume 19, Issue 5, October 2005, Pages 703-704

pineal gland and extracerebral blood vessels folowing sympathectomy

Following removal of the superior cervical ganglion (SCG), large molecular weight (MW) NGF species, including proNGF-A, were increased in distal intracranial SCG targets, such as pineal gland and extracerebral blood vessels (bv).

Brain Research; Research from Miami University provides new data about brain research

Science Letter. Atlanta: May 15, 2007. pg. 1746

The HPA axis regulates the secretion of glucocorticoids (GCs), which play important roles in diverse brain functions, including cognition, emotion

Several neurological diseases are frequently accompanied by dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis. The HPA axis regulates the secretion of glucocorticoids (GCs), which play important roles in diverse brain functions, including cognition, emotion, and feeding. Under physiological conditions, GCs are adaptive and beneficial; however, prolonged elevations in GC levels may contribute to neurodegeneration and brain dysfunction. In the current study, we demonstrate that apolipoprotein E (apoE) deficiency results in age-dependent dysregulation of the HPA axis through a mechanism affecting primarily the adrenal gland.
The Journal of Neuroscience, March 1, 2000, 20(5):2064-2071

peripheral sympathetic denervation may modulate immune function via activation of the hypothalamic-pituitary-adrenal (HPA) axis

Together, these findings suggest that peripheral sympathetic denervation may modulate immune function via activation of the hypothalamic-pituitary-adrenal (HPA) axis.

Ann N Y Acad Sci. 2000;917:923-34.

Increasing evidence suggests that the detrimental effects of glucocorticoid (GC) hypersecretion occur by activation of the hypothalamic-pituitary-adrenal (HPA) axis in several human pathologies, including obesity, Alzheimer's disease, AIDS dementia, and depression. The different patterns of response by the HPA axis during chronic activation are an important consideration in selecting an animal model to assess HPA axis function in a particular disorder.

Detrimental effects of chronic hypothalamic-pituitary-adrenal axis activation. From obesity to memory deficits
Raber J Mol Neurobiol 1998 Aug; 18(1): 1-22

redistribution of cerebral bloodflow following sympathectomy

SM Mueller, DD Heistad and ML Marcus

Effect of sympathetic denervation in dogs.
Total and regional cerebral blood flow during hypotension, hypertension, and hypocapnia.

The major new findings in this study are, first, that hypotension produces a redistribution of CBF which tends to preserve blood flow to brainstem and to cerebral gray matter...

1977 American Heart Association

cerebrovascular CO2 reactivity

Acta Physiol Scand. 1977 Sep;101(1):122-5.Links

Effects of intraventricular 6-hydroxydopamine on cerebrovascular CO2 reactivity in anesthetized rats.

Edvinsson L, Hardebo JE, MacKenzie ET.

Regional cerebral blood flow was measured by the 14C-ethanol technique in anesthetized rats before and after intraventricular injection of 6-hydroxydopamine. This treatment reduced the fluorescence of the central noradrenaline and dopamine nerve terminals, as well as of the perivascular nerve terminals in cerebral vessels. The administration of 6-hydroxydopamine had no significant effect on cerebral blood flow at normocapnia. The cerebrovascular reactivity to hypercapnia was significantly increased in the 6-hydroxydopamine treated animals. The results indicate an involvement of central catecholamine pathways in the cerebrovascular reactivity to hypercapnia.

PMID: 906856 [PubMed - indexed for MEDLINE]

Structural changes of arteries after sympathectomy

The findings indicate that in renal hypertensive rats structural changes of both large arteries and veins may develop in the absence of an intact sympathoadrenergic system.

Effect of sympathectomy on arterial and venous changes in renal hypertensive rats

G. Simon
Am J Physiol Heart Circ Physiol 241: H449-H454, 1981;

Tumor necrosis factor-a induces oligodendrocytes apoptosis

Tumor necrosis factor-a induces oligodendrocytes apoptosis, and is known to stimulate the hydrolysis of sphingomyelin to form the lipid mediator, ceramide.
http://www.springerlink.com/content/mu032lj427l85701/

Oligodendrocyte apoptosis and primary demyelination

We demonstrate that local production of TNF (tumor necrosis factor) by central nervous system glia potently and selectively induces oligodendrocyte apoptosis and myelin vacuolation in the context of an intact blood-brain barrier and absence of immune cell infiltration into the central nervous system parenchyma. Interestingly, primary demyelination then develops in a classical manner in the presence of large numbers of recruited phagocytic macrophages, possibly the result of concomitant pro-inflammatory effects of TNF in the central nervous system, and lesions progress into acute or chronic MS-type plaques with axonal damage, focal blood-brain barrier disruption, and considerable oligodendrocyte loss. Both the cytotoxic and inflammatory effects of TNF were abrogated in mice genetically deficient for the p55TNF receptor demonstrating a dominant role for p55TNF receptor-signaling pathways in TNF-mediated pathology.
http://www.ncbi.nlm.nih.gov/pubmed/9736029

Sympathectomy frequently causes perioperative hypotension

Vasomotor output is modified by inputs from throughout the central nervous system, including the hypothalamus, cerebral cortex, and the other areas in the brain stem. Areas in the posterolateral medulla receive input from both the vagal and the glossopharyngeal nerves and play an important role in mediating a variety of circulatory reflexes. The sympathetic system normally maintains some tonic vasoconstriction on the vascular tree. Loss of this tone following induction of anesthesia or sympathectomy frequently contributes to perioperative hypotension.

Clinical Anesthesiology

By G. Edward Morgan, Maged S. Mikhail, Michael J. Murray

Published by McGraw-Hill Professional, 2005

ISBN 0071423583, 9780071423588

autoregulatory breakthrough is eliminated when the arterial baroreflex is interrupted

The effects of sympathetic section blockade are greater during systemic hypercapnia than during normocapnia: a decrease in cerebrovascular resistance has been demonstrated in cats and rabbits after bilateral sympathectomy when PaCO2 was below 62-67 mmHg.
Blockade of sympathetic activity causes a significant further increase in CBF during hypoxia.

..sympathetic activation exerts a significant protective action on CBF and blood-brain barrier (BBB) permeability (Bill and Lander 1976) an effect which is also seen in the presence of moderate increase increases in BP, where autoregulation maintains CBF almost constant.

The vasodilation which characterizes autoregulatory breakthrough is eliminated when the arterial baroreflex is interrupted (Talman et al. 1994), which suggests that it is an active process. It is possible that the breakthrough depends on release of nitric oxide or a NO donor associated with the removal of the sympathetic innervation of cerebral vessels (Talman and Dragon 1995).

Intoxications of the Nervous System

By Pierre J. Vinken, F. A. de Wolff, George W. Bruyn, Otto Appenzeller, Harold L. Klawans

Published by Elsevier Health Sciences, 1999

ISBN 0444828133, 9780444828132

risk of vascular insufficieny and subsequent dysfunction of thoracolumbar autonomic outflow to the head and neck

Cadaveric studies of the blood supply to the human cervical sympathetic chain and ganglia are lacking in the English literature. This study seeks to elucidate the gross blood supply of the cervical sympathetic chain so as to avoid surgical disruption of these vessels and thus decrease the risk of vascular insufficieny and subsequent dysfunction of thoracolumbar autonomic outflow to the head and neck.

Conclusions: Although sympathetic injury is a rare consequence of cervical operations, the current data should be useful to the surgeon who operates in the cervical region so as to avoid potential complications from disruption of the primary blood supply of the cervical sympathetic chain and ganglia.
European Journal of Morphology, Volume 40, Issue 5 December 2002 , pages 283 - 288
http://www.informaworld.com/smpp/content~content=a725290831~db=all

Effects of surgical sympathectomy on catecholamine concentrations in the posterior pituitary

Approximately one-third of the norepinephrine in the posterior pituitary of the rat is contained in terminals of sympathetic nerves which originate in the superior cervical ganglia; the remaining norepinephrine and dopamine appear to be in nerves of central origin.

completely depleted from the pineal gland. These results suggest that NE in the pineal gland ... amine declines following sympathectomy. Bjrrklund et al.
http://www.springerlink.com/content/qp13674817684227/

Effect of adrenalectomy or sympathectomy on spinal cord blood flow

We conclude that adrenalectomy near-totally ablates the hypothermia-associated increase in RSCBF (regional spinal cord blood flow) measured in intact rats and that abdominal sympathectomy totally ablates it. This evidence complements morphological evidence for adrenergic innervation of the spinal cord vasculature.

Heart and Circulatory Physiology, Vol 260, Issue 3 827-H831, Copyright © 1991 by American Physiological Society

Sympathetic regulation of the cerebral circulation by the carotid chemoreceptor reflex

After bilateral cervical sympathectomy (n = 9), carotid chemoreceptor reflex stimulation induced significantly different (P less than 0.01) effects on cerebral blood flow, which rose by 42 +/- 8%, and cerebral vascular resistance, which did not change.
In "sham" dogs, the repeat response to carotid chemoreceptor stimulation also induced significantly different effects from those in dogs with sympathectomy. Thus, in the conscious dog, stimulation of the carotid chemoreceptor reflex elicits significant sympathetically mediated vasoconstriction in cerebral vessels.
Am J Physiol Heart Circ Physiol 238: H594-H598, 1980;

CEREBRAL ISCHEMIA FOLLOWING SYMPATHECTOMY

Two patients died during follow-up: 1 of myocardial infarction and 1 of cerebral ischemia, 24 and 32 months, respectively, after the operation. ...

ats.ctsnetjournals.org/cgi/content/full/74/3/885

sympathectomy leading to an extracranial steal phenomenon

The incidence and extension of brain infarcts was increased in animals with additional ipsilateral cervical preganglionic sympathectomy. Sympathectomy did not affect markedly the respiration and systemic circulation. The effect of sympathectomy was attributed to a cutaneous vasodilation, leading to an extracranial steal phenomenon.

J Neurol Neurosurg Psychiatry. 1983 August; 46(8): 768–773.

cerebral autoregulation was impaired - depletion of brain noradrenaline levels causes a disturbance in cerebral microvascular tone

CBF increased significantly after the elevation of systemic blood pressure compared with that in the control group, and cerebral autoregulation was impaired. After a 1-hour study, the specific gravity of the cerebral tissue in the treated group significantly decreased; electron microscopic studies at that time revealed brain edema. It is suggested that depletion of brain noradrenaline levels causes a disturbance in cerebral microvascular tone and renders the cerebral blood vessels more vulnerable to hypertension.

J Neurosurg. 1991 Dec;75(6):906-10.

Peripheral sympathectomy prevents the normal occurrence of a variety of bodily changes

"Peripheral sympathectomy prevents the normal occurrence of variety of bodily changes and hence, a fortiori, prevents sensory feedback of those changes" (p.68)
Biology and Emotion By Neil NcNaughton
Cambridge University Press 1989

Melatonin production abolished after sympathectomy

Cervical sympathetic nerves may affect blood adrenocorticotropic hormone (ACTH), cortisol (CS), melatonin or serotonin levels. We examined whether stellate ganglion block (SGB), which inhibits this nerve conduction, affects these substances.

During surgery, melatonin circadian rhythm and serotonin levels did not change, but melatonin increased only at night and serotonin decreased after surgery. These findings suggested that some stress stimuli are conducted via cervical sympathetic nerves to the hypothalamus, which is reduced by SGB, and to the pineal gland at night, which causes increased melatonin and decreased serotonin levels.

Authors: Iwama, Hiroshi; Son, Syoraku; Watanabe, Kazuhiro

Source: The Pain Clinic, Volume 13, Number 3, 2001 , pp. 233-244(12)

Publisher: Maney Publishing

Melatonin production abolished after sympathectomy

The amount of 6-sulphatoxymelatonin, the chief metabolite of melatonin, in the urine was measured in nine patients, who were subjected to
bilateral sympathectomy at the second thoracic ganglionic level for treatment of hyperhidrosis of the palms. All patients showed before surgery had a normal 6-sulphatoxymelatonin excretion with a peak in the excretion during the night time. After the sympathectomy, the high night time excretion
was clearly abolished in five patients but remained high in four patients. This indicates that the segmental locations of the preganglionic sympathetic perikarya in the spinal cord, stimulating the melatonin secretion in the pineal gland in humans, vary between individuals.
© 2006 Elsevier Ireland Ltd. All rights reserved.
Molecular and Cellular Endocrinology 252 (2006) 40–45


Melatonin
Melatonin is an important immunomodulator and is the principal means by which tissues are synchronized to the daily cycle of light exposure and physical actity. Cortisol, on the other hand, is critical for maintaining energy homeostasis and modulating immune function. Melatonin and cortisol tend to run opposite to each other.
Deviations from the normal patterns for these hormones can have significant implications for overall health and future risk of cancer. In fact, research shows that low melatonin and high cortisol are independently associated with some of the same health conditions.
Consequently, the balance between these two hormones is important to overall good healt. The melatonin-cortisol index (MCI)s an innovative way of examining the balance between these two vital hormones. The MCI may be used to assess cancer risk and immune function, and may also aid in the assessment of depression, heart disease, osteoporosis and weight management issues.
Melatonin | Rocky Mountain Analytical Lab
http://www.rmalab.com/index.php?id=61

Changes in hemodynamics of the carotid and middle cerebral arteries before and after endoscopic sympathectomy

Sixty-eight patients with PH (35 males and 33 females) for whom the average age was 24.5 ± 10.7 years (± standard deviation) were recruited into this study. These patients all underwent routine upper T-2 sympathectomy to treat their PH. Ultrasonography studies of the carotid arteries (CAs) and MCA were obtained in each patient before and after T-2 sympathectomy. The blood flow volume, flow velocity, and resistivity index (RI) in the bilateral common CAs (CCAs), internal CAs (ICAs), and external CAs (ECAs) were evaluated using duplex ultrasonography. The systolic peak velocity, mean velocity, diastolic peak velocity, pulsatility index, and RI of the bilateral MCAs were evaluated using transcranial Doppler ultrasonography. Blood pressure and heart rate were also recorded during this study. The Student paired t-test was used to analyze the differences between studies before and after bilateral T-2 sympathectomy. There was a significant reduction in diastolic pressure after T-2 sympathectomy (p = 0.003), but not in systolic pressure or heart rate. The vessel diameter was increased after sympathectomy in the left CAs and right CCA. The T-2 sympathectomy led to significant elevation of blood flow volume and RI in the left CCA, ICA, and ECA (p <>

Conclusions. Patients who underwent T-2 sympathectomy demonstrated a significant increase in blood flow volume and flow velocities of the CAs and MCA, especially on the left side. Asymmetry of sympathetic influence on the hemodynamics of the CAs and MCA was noted.

http://thejns.org/doi/abs/10.3171/jns.1999.90.3.0463

The effect of cerebral ischemia was virtually indistinguishable from the action of Cervical Sympathectomy itself

Some workers suggest a possible "transmembrane" role of PG in the nervous system.

If the increase in the PG level during ischemia is regarded as a protective reaction, it must be admitted that no increase took place 1 day after CSE (cervical sympathectomy) and it was considerably weakened 7-40 days after CSE.

The effect of cerebral ischemia was virtually indistinguishable from the action of CSE itself.

It can be tentatively suggested that PGF plays the main role in the regulation of tone of the vascular wall and in the regulation of metabolism under conditions of ischemia when the sympathetic regulation is disturbed.

http://www.springerlink.c...ontent/j705306763158841/

Middle cerebral artery blood velocity during exercise with beta-1 adrenergic and unilateral stellate ganglion blockade in humans

A reduced ability to increase cardiac output (CO) during exercise limits blood flow by vasoconstriction even in active skeletal muscle. Such a flow limitation may also take place in the brain as an increase in the transcranial Doppler determined middle cerebral artery blood velocity (MCA V(mean)) is attenuated during cycling with beta-1 adrenergic blockade and in patients with heart insufficiency. We studied whether sympathetic blockade at the level of the neck (0.1% lidocaine; 8 mL; n=8) affects the attenuated exercise - MCA V(mean following cardio-selective beta-1 adrenergic blockade (0.15 mg kg(-1) metoprolol i.v.) during cycling.

During control cycling the right and left MCA V(mean) increased to the same extent (11.4 +/- 1.9 vs. 11.1 +/- 1.9 cm s(-1)). With the pharmacological intervention the exercise CO (10 +/- 1 vs. 12 +/- 1 L min(-1); n=5), HR (115 +/- 4 vs. 134 +/- 4 beats min(-1)) and delta MCA V(mean) (8.7 +/- 2.2 vs. 11.4 +/- 1.9 cm s(-1) were reduced, and MAP was increased (100 +/- 5 vs. 86 +/- 2 mmHg; P <>

http://www.ncbi.nlm.nih.gov/pubmed/10971220

Compensatory Hyperhidrosis is a result of a lack of negative feedback to the hypothalamus after sympathectomy

"CH (compensatory hyperhidrosis) is a result of a lack of negative feedback to thehypothalamus after sympathectomy"

J. bras. pneumol. vol.34 no.11 São Paulo Nov. 2008

Cutaneous vasodilator responses induced by activation of hypothalamic heat loss mechanisms are completely abolished by sympathectomy

http://www3.interscience.wiley.com/journal/121531565/abstract

SYMPATHETIC-NERVE STIMULATION IN HUMANS INCREASES MIDDLE CEREBRAL-ARTERY BLOOD-FLOW VELOCITY

The effect of electric stimulation of the sympathetic cord in the upper thoracic level on the middle cerebral artery blood flow veloCitY (V(MCA)) in humans was examined using transcranial Doppler sonography monitoring during surgery for palmar hyperhidrosis. Sympathetic stimulation resulted in marked and rapid increases Of V(MCA). The responses were preceded by prompt increases of mean arterial blood pressure (MABP) and heart rate (HR). Division of the sympathetic cord cranially or caudally to the stimulation site partially reduced the V(MCA), MABP and HR responses. Both these operations reduced sympathetic pathways to the heart as reflected by a decrease in HR and MABP. The integrity of the sympathetic pathway from the stimulation site through the superior cervical ganglion and the carotid plexus was not a prerequisite for a V(MCA) response. Our data suggest that the V(MCA) increase mainly results from stimulation of the heart and the cardiovascular system, resulting in marked increases of blood pressure and heart rate.

CEREBROVASCULAR DISEASES Volume: 2 Issue: 6 Pages: 359-364 Published: NOV-DEC 1992

Impaired autonomic function results in impaired cerebral regulation

The absence of an increase in the power of 0.1 Hz blood pressure and cerebral blood flow velocity oscillations confirmed autonomic neuropathy in the diabetic patients. Gain analysis did not show altered cerebral regulation. The decrease in phase shift in the patients indicates a more passive transmission of neck suction-induced blood pressure fluctuations onto the cerebrovascular circulation, i.e. altered cerebral regulation, in the patients, and is therefore suited to identifying subtle impairment of cerebral regulation in these patients.
http://www.springerlink.com/content/14m7g478j7ux11hv/

Psychoneurological applications of endoscopic sympathetic blocks

In addition to more widely and longer known indications of ETS, various neurological disorders and psychologically stressful situations in their worst expressions might be alleviated by the reversible ESB procedure. The patients with social phobia, especially those who have also blushing and/or stage fright type of heart racing, benefit from the ESB. The disturbances of the sympathetic nervous system, e. g. in Parkinson's disease and multiple system atrophy might be alleviated with sympathetic block, especially the extrapyramidal symptoms in these diseases. In migraine, sympathetic surgery has been noted to give some help. The unilateral left-sided block has been effective in long QT-syndrome type arrhythmias. In schizophrenia, the phobic, paranoic or confusional reactions have been tentatively treated by the sympathetic block.
Clin Auton Res. 2003 Dec;13 Suppl 1:I20-1; discussion I21.

Carbon dioxide absorption into the blood during thoracoscopic surgery

Respiratory function and pulmonary gas exchange are affected in thoracoscopic procedures where a pneumothorax is introduced using CO2. Carbon dioxide absorption into the blood during thoracoscopic surgery using intrathoracic carbon dioxide insufflation may lead to respiratory acidosis, increased ventilation requirements, and possible serious cardiovascular compromise.
http://www.koreamed.org/SearchBasic.php?RID=173908&DT=1

Sympathethetic influence on Cerebral Blood Volume following excsion of the superior cervical ganglia

Shortly after operation there is a leakage of the noradrenaline transmitter from the degenerating nerve terminals with and accompanying activation of the vascular receptor (the CVB was foudn to be reduced by 28%). When the transmitter has disappeared from the degenerating terminals, the neural influence of the vessels is abolished (the blood volume was increased by 34% compared to unoperated controls). About 2 weeks later, a pronounced denervation supersensitivity of the vascular receptors to circulating catecholamines develops (the CVB became nromal or even subnormal).
Another circumstance giving the impression of inconsistent results after denervation is that a difference in the effects of pre- and postganglionic operation is usually not fully considered.
Cellular and Molecular Life Sciences
Volume 28, Number 7 / July, 1972

The HPA axis regulates the secretion of glucocorticoids (GCs), which play important roles in diverse brain functions, including cognition, emotion

Several neurological diseases are frequently accompanied by dysregulation ofthe hypothalamic-pituitary-adrenal (HPA) axis. The HPA axis regulates the secretion of glucocorticoids (GCs), which play important roles in diverse brain functions, including cognition, emotion, and feeding. Under physiological conditions, GCs are adaptive and beneficial; however, prolonged elevations in GC levels may contribute to neurodegeneration and brain dysfunction. In the current study, we demonstrate that apolipoprotein E (apoE) deficiency results in age-dependent dysregulation of the HPA axis through a mechanism affecting primarily the adrenal gland.
The Journal of Neuroscience, March 1, 2000, 20(5):2064-2071

Secretions of the pituitary-adrenal cortex as controllers of emotion

Peripheral sympathectomy prevents the normal occurrences of a variety of bodily changes and hence, a fortiori, prevents sensory feedback of those changes. (p.68)

By Neil McNaughton

Cambridge University Press, 1989

integration of somatosensory and phasic baroreceptor information at cortical, limbic and brainstem levels

J Neurosci. 2009 Feb 11;29(6):1817-25

Changes in cerebral morphology consequent to peripheral autonomic denervation

Neuroimage, 18(4).pp.908-916.

Cerebral Blood Flow after Sympathectomy

After sympathectomy, CBF (Cerebral Blood Flow) increases (26.5%+-3.6%) and CVR (Cerebral Vascular Resistance) decreases (-21.8%+-2.1%) during REM were less (p<0.05)

Hematology Week. Atlanta: Dec 29, 2008. pg.430

Ultrastructural changes in the pineal gland

H.J.Romijn

Journal of Neural Transmission

Springerlink

March 29, 2005

remarkable changes in the nerves that remain

The Autonomic Nervous System. Part 1, Normal Functions by O. Appenzeller

Category: Neurology & Clinical Neurophysiology

Publication date: 1999-12-16

Publisher: Elsevier - Health Sciences Div

pituitary secretions of ACTH and TSH after sympathectomy

Journal of Anesthesia, volume 10, Number 3/September, 1996

Extrapolation of these findings to humans suggests that longterm and repeated stellate ganglion block would affect the pituitary secretions of ACTH and TSH.

Dilation of major cerebral arteries and cranial noncerebral vasodilation following sympathectomy

Headache Following Cervical Sympathectomy

Headache. 43(4): 410-414, April 2003.

Spierings, Egilius L.H.MD, PhD

Changes in cerebral capillary bed

Changes in cerebral capillary bed following cervical sympathectomy.

Arch. Neurol. and Psychiat., 1929, 21, 1102.

Sympathectomy alters cranial nerves and cerebral blood flow

Moya-Moya Syndrome

Moya Moya syndrome is a vasculopathy of the cranial arteries, usually the carotids, leading to progressive intracranial occlusion with distal collateral vessels. This is a very frequent cause of pediatric stroke in India(10,11). Children usually present with an acute focal deficit such as hemiplegia, whereas in later years sub-arachnoid hemorrhage is a common presenta-tion. Due to bilateral carotid involvement sometimes alternating hemiplegia is seen. The outcome varies widely without treatment. Moya Moya disease is usually idiopathic, although same radiographic pattern is seen in some patients with sickle cell disease, neuro-fibromatosis, postcranial irradiation and in various other conditions(15). There is no proven treatment of Moya Moya disease. Medical management involves use of aspirin but needs further testing. Surgical treatment involves cervical sympathectomy, intracranial graft of omentum or temporalis muscle and bypass of superficial temporal artery to the middle cerebral artery(34).

http://indianpediatrics.net/feb2000/personal.htm

Role of the ANS in cerebral circulation

It is proposed that the autonomic innervation of brain vessels participates in the control not only of the cerebral circulation but also of associated intracranial pressure phenomena.
Blood Vessels 1974;11:2-31

Behavioral changes after sympathectomy

Six experiments are reported on the effects of 2,4,5-trihydroxyphenylethyl-amine (6-hydroxydopamine) on two-way escape and avoidance learning. Rats were tested on either escape or avoidance learning at 80 days of age after chemical sympathectomy at birth or 40 or 80 days of age. Neonatal and chronic sympathectomy (at 40 days), but not acute sympathectomy (at 80 days), resulted in depressed escape learning. Avoidance learning was affected by neonatal sympathectomy and partially by acute sympathectomy. The results have implications for the role of the autonomic nervous system in escape-avoidance learning.
J Comp Physiol Psychol 1976; 90:303-16.

Altered Cerebral Blood Flow following Sympathectomy

The subject has recently been studied by James, Millar&Purves who measured the cerebral vascular response to hypoxia with all nerves intact and following division or stimulation of the vagus and cervical sympathetic nerves. The effect of sympathectomy (...) is seen to consist of an elevation of both grey and white matter blood flow 40-50 per cent above control over the range of PaO2 tested, 35 to 440 mmHg. When the cervical sympathetic nerve as stimulated at constant frequency and intensity, cortical flow was reduced to control levels.

The Physiology of the Cerebral Circulation (Monographs of the Physiological Society) by M. J. Purves (Hardcover - May 31, 1972)

Sympathetic Innervation of Cerebral Arteries: Prejunctional Supersensitivity to Norepinephrine After Sympathectomy

© 1975 American Heart Association, Inc.

sympathectomy abolished the Psychogalvanic Reflex

Some P.G.R. studies in a female subject who had bilateral cervicalsympathectomy were described. It was found that sympathectomy abolished P.G.R. and that intra-arterial infusion of acetylcholine evoked marked P.G.R. changes in the sympathectomized limb. These findings support the theory that the P.G.R. is mediated through the cholinergic fibres of the sympathetic nervous system.

Submitted on May 22, 1967
The British Journal of Psychiatry (1968) 114: 639-642. doi: 10.1192/bjp.114.510.639
© 1968 The Royal College of Psychiatrists

sympathetic denervation-hypersensitivity and migraine

Regional cerebral blood flow (rCBF) and cerebral vasomotor responses to 5% CO₂ inhalation were measured before and after pharmacologic μ- or β-adrenoceptor manipulation in Migraine (M) and Cluster headaches (C).
There appears to be an asymmetrical adrenoceptor disorder in M and C possibly due to sympathetic denervation-hypersensitivity.

Headache: The Journal of Head and Face Pain

Volume 20 Issue 6, Pages 321 - 335

Published Online: 22 Jun 2005

http://www3.interscience.wiley.com/journal/119584269/abstract

SNS regulates cerebral blood flow

Thus, in the conscious dog, stimulation of the carotid chemoreceptor reflex elicits significant sympathetically mediated vasoconstriction in cerebral vessels.
Am J Physiol. 1980 Apr;238(4):H594-8.

sympathectomy results in an increased collagen content in the vascular wall

From animal experiments, it is known that long-term sympathectomy results in an increased collagen content in
the vascular wall, suggesting a stiffening of the vessel wall (9). Giannattasio et al.

MEDICINE & SCIENCE IN SPORTS & EXERCISE®
Copyright © 2005 by the American College of Sports Medicine
DOI: 10.1249/01.mss.0000174890.13395.e7

HPA-axis plays a crucial role in the development and intensity of autoimmune diseases

Like in man, in animals the HPA-axis plays a crucial role in the development and intensity of autoimmune diseases. Corticosteroids, in particular, are known to suppress T-cell induced autoimmune reaction in animal models, at the beginning, and are capable to support spontaneous recovery.

EAE derived data support that increased HPA-axis reactivity is accompanied by enlarged capacity to secrete and produce Th-2-cytokines. While decreased HPA-reactivity is accompanied by enlarged capacity to secrete and produce Th-1-cytokines.

Sympathectomy and axanotomy were accompanied by stress-induced increases of EAE immunological responses. Transferred Th1-cells of such sympathectomized animals to healthy animals resulted in increased EAE.
In: Research Focus on Cognitive Disorders ISBN 1-60021-483-5
Editor: Valerie N. Plishe © 2007 Nova Science Publishers, Inc.

Long-Term Denervation of Vascular Smooth Muscle Causes Not Only Functional but Structural Change

Rosemary D. Bevan, Hiromichi Tsuru

Department of Pharmacology, School of Medicine, University of California, Los Angeles, Calif.

Blood Vessels 1979;16:109-112 (DOI: 10.1159/000158197)

Reduced brain perfusion and cognitive performance

Chronically low blood pressure is accompanied by a variety of complaints including fatigue, reduced drive, faintness, dizziness, headaches, palpitations, and increased pain sensitivity [1–4]. In addition, hypotensive individuals report cognitive impairment, above all deficits in attention and memory. Nevertheless, it is generally the case that in research, as well as in clinical practice, relatively little importance is ascribed to hypotension. One reason for this is that, despite mental symptoms, cerebral dysfunction generally is not taken into account [1]. This is a consequence of the current doctrine that low systemic blood pressure is compensated by autoregulatory processes which prevent reduced blood perfusion of the brain [5, 6].

Some recent findings challenge this doctrine: reduced cognitive performance in hypotension has been demonstrated by neuropsychological testing, and EEG studies have revealed diminished cortical activity. Moreover, the assumption of unimpaired brain perfusion in hypotension no longer holds. In the present review the necessity of a reappraisal concerning hypotension is discussed in light of the relationship between blood pressure and cerebral functioning.

Clin Auton Res. 2007 April; 17(2): 69–76. Published online 2006 November 14. doi: 10.1007/s10286-006-0379-7.

PMCID:PMC1858602

Stefan Duschek and Rainer Schandry
Stefan Duschek, Phone: +49-89/2180-5297, Fax: +49-89/2180-5233, Email:duschek@psy.uni-muenchen.de

Sympathectomy: "suppression of the neuroendocrine stress response"

Neuraxial blocks typically produce variable decrease in blood pressure that might be accompanied by a decrease in heart rate and cardiac contractility. These effects are generally proportional to the degree (level) of the sympathectomy. Vasomotor tone is primarily determined by sympathetic fibres arising from T5 to L1, innervating arterial and venous smooth muscle. Blocking these nerves causes vasodilation of the venous capacitance vessels, pooling of blood, and decreased vvenous terurn to the heart; in some instances, arterial vasodilation may also decrease systemic vascular resistance. The effects of arterial vasodilation may be minimized by compensatory vasoconstriction above the level of the block. A high sympathetic block not only prevents compensatory vasoconstriction but also blocks the sympathetic cardiac accelerator fibres that arise at T1-T4.
Profound hypotension may result from vasodilation combined with bradycardia and decreased contractility. These effects are further exaggerated if venous return is further compromised by a head-up position or from the weight of a gravid uterus. Unopposed vagal tone in some persons may explain cardiac arrest with spinal anesthesia.
p.261

The sympathetic system normally maintains some tonic vasoconstriction on the vascular tree. Loss off this tone following induction of anesthesia or sympathectomy frequently contributes to perioperative hypotension.
p.375

AV conduction abnormalities are usually manifested by abnormal ventricular depolarization (bundle-branch block) prolongation of the P-R interval (first degree AV block) failure of some atrial impulses to depolarize the ventricles (second degree AV block) or AV dissociation (third degree AV block or complete heart block).
p.428

Clinical anesthesiology
By G. Edward Morgan, Maged S. Mikhail, Michael J. Murray
McGraw-Hill, Edition: 3 - 2002

hypoxaemia, a potentially serious complication of Sympathectomy

SpO2 decreased below 98% in 58 patients. Sudden hypotension and bradycardia in two patients.
The mean PaO2 was significantly (p = 0.03) decreased during two-lung ventilation (TLV), after reinflation of the right lung, compared with TLV after endobronchial intubation. There was no significant difference in mean PaO2 during one-lung ventilation of both lungs. Lowest PaO2 observed during one-lung ventilation was less than 13.3 kPa in three sympathectomies. Postoperative pain, severe on awakening and mainly retrosternal, was relieved with i.v. opiates. CONCLUSION: Controlled ventilation with 100% inspired O2, SpO2 monitoring and one to two gentle manual ventilations when it decreases is the cornerstone of the management of hypoxaemia, a potentially serious complication of TES.
Eur J Surg Suppl. 1994;(572):23-5.

hypotension-related poorer mental ability is also reflected in diminished cortical activity

EEG studies have demonstrated that the hypotension-related poorer mental ability is also reflected in
diminished cortical activity. Contrary to convention, more recent research has suggested a deficient regulation of cerebral blood flow in persons with low blood pressure. In addition to reduced tonic brain perfusion, studies demonstrated insufficient adjustment of blood flow to cognitive requirements.

Chronically low blood pressure is accompanied by a variety of complaints including fatigue, reduced drive, faintness, dizziness, headaches, palpitations, and increased pain sensitivity [1–4]. In addition, hypotensive individuals report cognitive impairment, above all deficits in attention and memory.
Clin Auton Res. 2007 April; 17(2): 69–76.

increased sensitivity to adrenaline is produced by sympathectomy alone

"The increased sensitivity to adrenaline is produced by sympathectomy alone. I think sensory denervation makes no difference."

Vascular Reactivity Following Sympathectomy

Chapter Author: R. T. Grant

Ciba Foundation Symposium - Peripheral Circulation in Man
Book Series: Novartis Foundation Symposia

Published Online: 27 May 2008

Editor(s): G. E. W. Wolstenholme, Jessie S. Freeman

Print ISBN: 9780470714706 Online ISBN: 9780470715185

the pineal capability of producing antigonadal substance is suppressed by cervical ganglionectomy

Pineal glands of male hamsters 8 weeks after removal of both eyes or both superior cervical ganglia and those of untreated animals were studied by electron microscopy. In the blinded hamsters the reproductive organs were remarkably involuted, whereas the pinealocytes enlarged and were characterized by a tremendous hypertrophy of the smoothsurfaced endoplasmic reticulum, in the mesh of which some dense cored vesicles were distributed. In contrast the pinealocytes of ganglionectomized hamsters atrophied and were noted by a large number of lysosomes and sparsity of the agranular reticulum, the testes being significantly larger than the controls. The findings were interpreted to be compatible with the view that the pineal capability of producing antigonadal substance is augmented by blinding and is suppressed by cervical ganglionectomy due to the impairment of normal functioning of the pineal by denervation.
Fine structural changes in the hamster pineal gland after blinding and superior cervical ganglionectomy
Cell and Tissue Research
Volume 158, Number 3 / May, 1975

Haematological changes during stress abolished by sympathectomy

To study haematological effects of emotional stress, blood samples were obtained from 29 healthy, normotensive, non-smoking males aged 20–34 years before, during and after 10 min of mental arithmetic. There were significant increases in pheripheral blood cell count, haemoglobin concentration, and haematocrit in response to mental stress. Parallel to these changes significant increases in heart rate, and systolic and diastolic blood pressure were observed. The relative increments of leucocyte (8%) and platelet (3·5%) count were significantly higher than the increase in haemoglobin concentration (2%). There was a significant positive correlation between the blood pressure increase and the mobilization of leucocytes, whereas the increase in erythrocyte count, haemoglobin concentration, and haematocrit showed significant positive correlations with heart rate reactivity. It is concluded that mental stress causes an increase in leucocyte and platelet count that could not solely be accounted for by the concurrent haemoconcentration.

The emotional leucocytosis observed in dogs has been claimed to be neurogenic in origin, since sympathectomy abolished the rise in leucocyte count (Garrey & Bryan, 19 3 5).
http://www3.interscience.wiley.com/journal/120731423/abstract

normal forearm vasodilator response to mental stress was absent months or years after surgical sympathectomy

Additional indirect evidence on this topic in humans comes from a study conducted in the 1950s (3). In this study, the normal forearm vasodilator response to mental stress was absent months or years after surgical sympathectomy.
J Appl Physiol
Vol. 92, Issue 5, 2019-2025, May 2002

Alteration in 'fight-or-flight response following sympathectomy

Mental arithmetic produces a psychophysiological arousal similar to the so-called defence-alarm reaction elicited by stimulation ofthe hypothalamic defence area in experimental animals (Folkow, 1982). This reaction pattern is characterized by increased heart rate, cardiac output and blood pressure, whereas total peripheral resistance is unchanged or decreased (Brod, 1970).

The increase of platelet concentration during psychological arousal is also in accordance with what has been observed in response to other stressors, i.e. physical exercise and adrenaline infusion (Sarajas et al, 1961; Gjerloff Schmidt & Waever Rasmussen, 1984; Dawson & Ogston, 1969; Vilen et al, 1980).

The emotional leucocytosis observed in dogs has been claimed to be neurogenic in origin, since sympathectomy abolished the rise in leucocyte count (Garrey & Bryan, 193 5).
Both alpha- and beta-receptors seem to be of importance in the mobilization of lymphocytes (Gader & Cash, 1975).

British Journal of Haematology. 1989. 71, 153-1 56

Sympathetic nerves protect against blood-brain barrier disruption

http://www.ncbi.nlm.nih.gov/pubmed/7064183?holding=ukpmc

sympathectomy may retard aversive conditioning

"Researchers have examined the role of autonomic feedback in emotional experience using the heartbeat paradigm. Katkin at al. (1982) found that some normal subjects can accurately detect their heartbeats, and it was those individuals who had a stronger emotional response to negative slides as determined by self-report (Hantas et al., 1982). Further support for the importance of autonomic feedback comes from observations. Experiments in animals demonstrate that sympathectomy may retard aversive conditioning (DiGusto and King, 1972), most likely because sympathectomy reduces fear.

In order for a feedback to occur, there must be a means for the viscera and autonomic nervous system to become activated.
Clinical neuropsychology
By Kenneth M. Heilman, Edward Valenstein
Oxford University Press

hypoxic pulmonary vasoconstriction may be impaired after Sympathectomy

It is well known that hypoxic pulmonary vasoconstriction(HPV) plays an important role to protect hypoxemia during the atelectasis induced by one-lung ventilation. Thoracic sympathectomy may have effects on pulmonary vasculature(HPV) and hemodynamics during one-lung anesthesia.

Mean arterial blood pressure was decreased from 81.9+/-2.89 to 73.2+/-2.49 mmHg after thoracic sympathectomy and heart rate was decreased from 104.4+/-3.12 to 88.2+/-2.31beats/min. Arterial oxygen tension was decressed from 570.5+/-17.9 to 521.4+/-23.2mmHg after position change, and decreased to 271.1+/-28.1 mmHg under one-lung ventilation, and finally decreased to 217.0+/-18.3 mmHg after thoracic sympathectomy. With the above results, we can conclude that patients for TES should be carefully observed during and after the procedure, and hypoxic pulmonary vasoconstriction may be impaired after TES.
Korean J Anesthesiol. 1993 Aug;26(4):695-699.

pineal gland and extracerebral blood vessels folowing sympathectomy

Following removal of the superior cervical ganglion (SCG), large molecular weight (MW) NGF species, including proNGF-A, were increased in distal intracranial SCG targets, such as pineal gland and extracerebral blood vessels (bv).

Brain Research; Research from Miami University provides new data about brain research

Science Letter. Atlanta: May 15, 2007. pg. 1746

peripheral sympathetic denervation may modulate immune function via activation of the hypothalamic-pituitary-adrenal (HPA) axis

Together, these findings suggest that peripheral sympathetic denervation may modulate immune function via activation of the hypothalamic-pituitary-adrenal (HPA) axis.

Ann N Y Acad Sci. 2000;917:923-34.

Increasing evidence suggests that the detrimental effects of glucocorticoid (GC) hypersecretion occur by activation of the hypothalamic-pituitary-adrenal (HPA) axis in several human pathologies, including obesity, Alzheimer's disease, AIDS dementia, and depression. The different patterns of response by the HPA axis during chronic activation are an important consideration in selecting an animal model to assess HPA axis function in a particular disorder.

Detrimental effects of chronic hypothalamic-pituitary-adrenal axis activation. From obesity to memory deficits
Raber J Mol Neurobiol 1998 Aug; 18(1): 1-22

The HPA axis regulates the secretion of glucocorticoids (GCs), which play important roles in diverse brain functions, including cognition, emotion

Several neurological diseases are frequently accompanied by dysregulation ofthe hypothalamic-pituitary-adrenal (HPA) axis. The HPA axis regulates the secretion of glucocorticoids (GCs), which play important roles in diverse brain functions, including cognition, emotion, and feeding. Under physiological conditions, GCs are adaptive and beneficial; however, prolonged elevations in GC levels may contribute to neurodegeneration and brain dysfunction. In the current study, we demonstrate that apolipoprotein E (apoE) deficiency results in age-dependent dysregulation of the HPA axis through a mechanism affecting primarily the adrenal gland.
The Journal of Neuroscience, March 1, 2000, 20(5):2064-2071

Peripheral sympathectomy prevents the normal occurrence of a variety of bodily changes

"Peripheral sympathectomy prevents the normal occurrence of variety of bodily changes and hence, a fortiori, prevents sensory feedback of those changes" (p.68)
Biology and emotion By Neil NcNaughton
Cambridge University Press 1989

collateral effects of thoracic sympathectomy not disclosed to patients

Several reports also demonstrate significantly lower heart rate increases during exercise in subjects who have undergone bilateral ISS [9–12] compared to pre-surgical levels. In spite of this high occurrence, recent reviews on the usual collateral effects of thoracic sympathectomy still do not include these possible cardiac consequences [6].
Eur J Cardiothorac Surg 2001;20:1095-1100

sympathectomy leading to an extracranial steal phenomenon

The incidence and extension of brain infarcts was increased in animals with additional ipsilateral cervical preganglionic sympathectomy. Sympathectomy did not affect markedly the respiration and systemic circulation. The effect of sympathectomy was attributed to a cutaneous vasodilation, leading to an extracranial steal phenomenon.
J Neurol Neurosurg Psychiatry. 1983 August; 46(8): 768–773.

sympathectomy on cerebral blood flow

CBF increased significantly after the elevation of systemic blood pressure compared with that in the control group, and cerebral autoregulation was impaired. After a 1-hour study, the specific gravity of the cerebral tissue in the treated group significantly decreased; electron microscopic studies at that time revealed brain edema. It is suggested that depletion of brain noradrenaline levels causes a disturbance in cerebral microvascular tone and renders the cerebral blood vessels more vulnerable to hypertension.
J Neurosurg. 1991 Dec;75(6):906-10.

Several reports also demonstrate significantly lower heart rate increases during exercise in subjects who have undergone bilateral ISS [9–12] compared to pre-surgical levels. In spite of this high occurrence, recent reviews on the usual collateral effects of thoracic sympathectomy still do not include these possible cardiac consequences [6].
Eur J Cardiothorac Surg 2001;20:1095-1100

Sympathethetic influence on Cerebral Blood Volume following excsion of the superior cervical ganglia

Shortly after operation there is a leakage of the noradrenaline transmitter from the degenerating nerve terminals with and accompanying activation of the vascular receptor (the CVB was foudn to be reduced by 28%). When the transmitter has disappeared from the degenerating terminals, the neural influence of the vessels is abolished (the blood volume was increased by 34% compared to unoperated controls). About 2 weeks later, a pronounced denervation supersensitivity of the vascular receptors to circulating catecholamines develops (the CVB became nromal or even subnormal).
Another circumstance giving the impression of inconsistent results after denervation is that a difference in the effects of pre- and postganglionic operation is usually not fully considered.
Cellular and Molecular Life Sciences
Volume 28, Number 7 / July, 1972

bilateral ganglionectomy resulted in minor decreases in the cerebrovascular contents of ACh

The effects of uni- or bilateral surgical ablation of the SPG, a putative origin of the cholinergic cerebrovascular innervation, were investigated on these two specific cholinergic markers at various postoperative times. ChAT activity and ACh levels were enriched in the cerebral as compared to the peripheral arteries. Among the cerebrovascular tissues tested, ACh levels were particularly high in the circle of Willis and the vertebrobasilar segments and, to a lesser extent, in the middle cerebral artery. Lower levels were found in the small pial vessels and choroid plexus. Overall, ChAT activity measured in different arterial beds paralleled the distribution of ACh. Following uni- or bilateral removal of the SPG, slight reductions were observed in ChAT activity in rostral cerebral arteries and pial vessels overlying the frontal cortex. Similarly, bilateral ganglionectomy resulted in minor decreases in the cerebrovascular contents of ACh in these same vascular segments.
J Cereb Blood Flow Metab. 1991 Mar;11(2):253-60.

Superior cervical ganglionectomy caused a marked decrease in noradrenaline concentrations in major cerebral arteries

Superior cervical ganglionectomy caused a marked decrease in noradrenaline concentrations in major cerebral arteries (−77%), although the reduction was less pronounced (−34%) in small pial vessels. Sympathectomy decreased by 33% 5-HT concentrations in the major cerebral arteries but was without effect on 5-HT levels in the small pial vessels.

Journal of Neurochemistry

Volume 56 Issue 2, Pages 681 - 689

Published Online: 5 Oct 2006

Received March 28, 1990 revised manuscript received July 12, 1990; accepted August 14, 1990.

SYMPATHETIC-NERVE STIMULATION IN HUMANS INCREASES MIDDLE CEREBRAL-ARTERY BLOOD-FLOW VELOCITY

The effect of electric stimulation of the sympathetic cord in the upper thoracic level on the middle cerebral artery blood flow veloCitY (V(MCA)) in humans was examined using transcranial Doppler sonography monitoring during surgery for palmar hyperhidrosis. Sympathetic stimulation resulted in marked and rapid increases Of V(MCA). The responses were preceded by prompt increases of mean arterial blood pressure (MABP) and heart rate (HR). Division of the sympathetic cord cranially or caudally to the stimulation site partially reduced the V(MCA), MABP and HR responses. Both these operations reduced sympathetic pathways to the heart as reflected by a decrease in HR and MABP. The integrity of the sympathetic pathway from the stimulation site through the superior cervical ganglion and the carotid plexus was not a prerequisite for a V(MCA) response. Our data suggest that the V(MCA) increase mainly results from stimulation of the heart and the cardiovascular system, resulting in marked increases of blood pressure and heart rate.

CEREBROVASCULAR DISEASES Volume: 2 Issue: 6 Pages: 359-364 Published: NOV-DEC 1992

Autonomic neural control of cerebral hemodynamics

it has been found that in humans CBFV in the middle cerebral artery decreased substantially during
lower body negative pressure (LBNP) and head-up tilt in the absence of systemic hypotension, which suggests the presence of cerebral vasoconstriction associated with augmented sympathetic nerve activity during orthostatic stress.
IEEE Eng Med Biol Mag. 2009 Nov-Dec;28(6):54-62.

Increased cerebral vasoconstriction or reduced vasomotion also may attenuate CBFV variability

Altered cerebral hemodynamics in early Alzheimer disease: a pilot study using transcranial Doppler.

J Alzheimers Dis. 2009 Jul;17(3):621-9.

In patients with sympathetic failure, the orthostatic reduction in cerebral blood velocity and oxygenation is larger

In patients with sympathetic failure, the orthostatic reduction in cerebral blood velocity and oxygenation is larger. Patients who become symptomatic within 5 minutes of standing are characterized by a pronounced orthostatic fall in bloodpressure, cerebral blood velocity, and oxygenation manifest within the first 10 seconds of standing.
Stroke. 2000;31:1608-1614

Obviously, it is not simply a compensatory hyperhidrosis transposition from postoperative reduction

In contrast, it is of particular interest to find that patients with cerebroischemic syndrome who received thoracic sympathectomy rarely developed substantial postsympathectomy compensatory hyperhidrosis (PCH). The etiology of PCH is still unclear. Obviously, it is not simply a compensatory hyperhidrosis transposition from postoperative reduction of palmar sweating. Based on our observations, we postulated two possible mechanisms. The first of these mechanisms is denervation hypersensitivity of the surgically injured distalsympathetic stump. This could explain why CH may appear soon after sympathectomy, but is not found in patients who undergo local excision of axillary sweat glands or undergo local treatment. Another mechanism is regeneration of preganglionic fibers or collateral sprouting of sympathetic fibers from the proximal stump of the sympathetic trunk. This could explain the long-term existence of PCH.
Ann Thorac Surg 2001;72:667-668

Receptor hypersensitivity is a common problem after significant sympathetic injury, including clammy hands, erythema, and allodynia. When sympathetic nerves regenerate, they may establish aberrant connections to sensory receptors, muscles, or other sympathetics receptors; this may lead to an over-response or abnormal response.
http://wiki.cns.org/wiki/index.php/Injury,_Sympathetic_Nerve

effect of electric stimulation of the sympathetic cord in the upper thoracic level on the middle cerebral artery blood flow

Source: CEREBROVASCULAR DISEASES Volume: 2 Issue: 6 Pages: 359-364 Published: NOV-DEC
1992
Times Cited: 20 References: 41
Abstract: The effect of electric stimulation of the sympathetic cord in the upper thoracic level on the middle cerebral artery blood flow veloCitY (V(MCA)) in humans was examined using transcranial Doppler sonography monitoring during surgery for palmar hyperhidrosis.
Sympathetic stimulation resulted in marked and rapid increases Of V(MCA). The responses were preceded by prompt increases of mean arterial blood pressure (MABP) and heart rate (HR).
Division of the sympathetic cord cranially or caudally to the stimulation site partially reduced the V(MCA), MABP and HR responses. Both these operations reduced sympathetic pathways to the heart as reflected by a decrease in HR and MABP. The integrity of the sympathetic pathway from the stimulation site through the superior cervical ganglion and the carotid plexus was not a prerequisite for a V(MCA) response. Our data suggest that the V(MCA) increase mainly results from stimulation of the heart and the cardiovascular system, resulting in marked increases of blood
pressure and heart rate.

Importance of bilateral sympathetic innervation on cerebral blood flow autoregulation in the thalamus

Brain Res. 1987 Jun 16;413(2):297-301.

Effects of bilateral sympathetic innervation on the regulation of cerebral blood flow to the thalamus were examined in spontaneously hypertensive rats (SHR). The superior cervical ganglion was removed on one side or bilaterally, and blood flow in the thalamus was repeatedly measured with a hydrogen clearance technique during a stepwise increase in arterial pressure. Sympathectomy on one side neither had effects on the pressure-flow relationship nor on the blood pressure levels of upper limits of autoregulation in the ipsilateral thalamus. In contrast, bilateral sympathetic denervation impaired the autoregulatory function in the thalamus and the upper limits were significantly lower than those in intact rats: 206 +/- 8 vs 226 +/- 10 mm Hg, respectively (P less than 0.02).
PMID: 3607478 [PubMed - indexed for MEDLINE]

The cerebral vessels became hypersensitive to epinephrine after cervical sympathectomy

The cerebral vessels became hypersensitive to epinephrine after cervical sympathectomy.
HERTZMAN, A. B., AND DILLON, J. B.
Annual Review of Physiology
Vol. 4: 187-214 (Volume publication date March 1942)

Imbalance of regional cerebral blood flow and oxygen consumption: effect of vascular alpha adrenoceptor blockade

Cerebral venous O2 saturations (a measure of cerebral O2 supply/consumption balance) were found to be significantly heterogeneous under control conditions. The coefficient of variation (CV = 100 x SD/mean) averaged 18%. The average cerebral venous O2 saturation was 59 +/- 11%. Administration of N-methyl chlorpromazine significantly reduced this heterogeneity through a reduction in the number of veins with low O2 saturations (CV = 11%). The average value increased slightly but significantly to 62 +/- 8%. Thus, N-methyl chlorpromazine eliminated many microregions of high O2 extraction. This indicated that vascular alpha adrenoceptors limit cerebral blood flow to some of the brain regions.
Neuropharmacology. 1993 Mar;32(3):297-302.

Imbalance of regional cerebral blood flow and oxygen consumption: effect of vascular alpha adrenoceptor blockade

Cerebral venous O2 saturations (a measure of cerebral O2 supply/consumption balance) were found to be significantly heterogeneous under control conditions. The coefficient of variation (CV = 100 x SD/mean) averaged 18%. The average cerebral venous O2 saturation was 59 +/- 11%. Administration of N-methyl chlorpromazine significantly reduced this heterogeneity through a reduction in the number of veins with low O2 saturations (CV = 11%). The average value increased slightly but significantly to 62 +/- 8%. Thus, N-methyl chlorpromazine eliminated many microregions of high O2 extraction. This indicated that vascular alpha adrenoceptors limit cerebral blood flow to some of the brain regions.
Neuropharmacology. 1993 Mar;32(3):297-302.