"Sympathectomy is a technique about which we have limited knowledge, applied to disorders about which we have little understanding." Associate Professor Robert Boas, Faculty of Pain Medicine of the Australasian College of Anaesthetists and the Royal College of Anaesthetists The Journal of Pain, Vol 1, No 4 (Winter), 2000: pp 258-260
Other potential complications include inadequate resection of the ganglia, gustatory sweating, pneumothorax, cardiac dysfunction, post-operative pain, and finally Horner’s syndrome secondary to resection of the stellate ganglion.
www.ubcmj.com/pdf/ubcmj_2_1_2010_24-29.pdf
After severing the cervical sympathetic trunk, the cells of the cervical sympathetic ganglion undergo transneuronic degeneration
After severing the sympathetic trunk, the cells of its origin undergo complete disintegration within a year.
http://onlinelibrary.wiley.com/doi/10.1111/j.1439-0442.1967.tb00255.x/abstract
Sunday, April 13, 2008
Postoperative Autonomic Deficit
Aberrant regeneration following sympathectomy - Frey's Syndrome
The pattern is symmetrical with sweating involving the head and exceptionally the neck, and with flushing most apparent in the nose and cheek (Haxton 1948; Monro 1959, Fox et al. 1962; Drummond and Lance 1987).
Aberrant regeneration following sympathectomy can give rise to pathological gustatory facial flushing and sweating. Weeks, months, or years after cervicothoracic preganglionic sympathectomy, gustatory sweating and flushing may develop on the denervated side along with impaired thermoregulatory sweating. (Bloor 1969; Kurchin at al. 1977)
Sympathetic preganglionic fibers originally destined for the salivary glands may be responsible through faulty reinnervation of the stellate ganglion... (Bloor, 1969; Drummond and Lance 1987).
Interruption of postganglionic sympathetic facial fibers may render residual neurilemmal sheaths and sympathetic endings susceptible to stray collateral sprouting or faulty regeneration of parasympathetic fibers that normally mediate salivation.
Pathological gustatory sweating and flushing can develop
after injury to preganglionic cervicothoracie sympathetic fibres, an
unavoidable consequence of resecting that part of the sympathetic chain. The
mechanism of this abnormal response is uncertain; conceivably, though,
regeneration of injured salivatory fibres or collateral sprouting from nearby
intact fibres creates aberrant connections between salivatory fibres and
denervated vasomotor and sudomotor neurons in the superior cervical ganglion. 7
Commands to salivate would then be translated into commands to sweat and flush
in the distribution of sympathetic denervation. Cross-innervation lower down in
the stellate ganglion can also produce unusual and potentially distressing
autonomic disturbances in the sympathetically denervated arm (e.g.
piloerection while eating)
P.D.DRUMMOND
School of Psychology, Murdoch University,
South Street, Murdoch,
Chronic Idiopathic Anhidrosis - Consequence of Sympathectomy
gustatory sweating occurred in 32% of patients
The questionnaire was returned by 96% of patients after a median of 17 months. Overall, gustatory sweating occurred in 32% of patients, and the incidence was significantly associated with extent of sympathectomy (p = 0.04). However, because the extent of sympathectomy was always decided by the location of primary hyperhidrosis, the latter may also explain the risk of gustatory sweating.
Gustatory Side Effects After Thoracoscopic Sympathectomy
Department of Cardiothoracic Surgery, Skejby Sygehus, Aarhus University Hospital, Aarhus, Denmark
Copyright © 2006 The Society of Thoracic Surgeons Published by Elsevier Inc.
http://ats.ctsnetjournals.org/cgi/content/abstract/81/3/1043
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6T11-4J963XN-1R&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=7cad987402b12485375284dc221ec19b
NE Loss Causes Motor Impairment
Departments of *Human Genetics and Environmental and Occupational Health, Rollins School of Public Health, Emory University, Atlanta, GA 30322; and Department of Physiology and Pharmacology, College of Veterinary Medicine, University of Georgia, Athens, GA 30602
Edited by Richard D. Palmiter, University of Washington School of Medicine, Seattle, WA, and approved June 25, 2007 (received for review March 27, 2007)
http://www.pnas.org/cgi/content/full/104/34/13804
NE Loss Causes Motor Impairment. We suggest two possible mechanisms for the motor impairments of Dbh–/– and LC-lesioned mice. SI Fig. 6).
Depression of T cell immunity following chemical sympathectomy
Alterations in Sympathetic Noradrenergic Innervation in Lymphoid ...
Sympathetic neural modulation of the immune system. I. Depression of T cell immunity in vivo and in vitro following chemical sympathectomy. Brain Behav. ...www.annalsnyas.org/cgi/content/full/840/1/262
depletion of brain noradrenaline levels causes a disturbance in cerebral microvascular tone
Thirty male Wistar rats, weighing 350 to 400 gm each, received stereotactic injections of 6-hydroxydopamine (300 micrograms/kg) into the left lateral ventricle. The same amount of saline was injected into a control group of 15 rats. Seven days after this procedure, cerebral blood flow (CBF) was measured by the hydrogen clearance method. A hypertensive condition at a mean arterial pressure of about 160 mm Hg was maintained for 1 hour by intravenous infusion of phenylephrine. In the 6-hydroxydopamine-treated group, 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. | |
Authors | H Kobayashi, M Hayashi, H Kawano, Y Handa, M Kabuto, H Ide (Affiliation: Department of Neurosurgery, Fukui Medical School, Matsuoka, Japan.) |
---|---|
Journal | Journal of neurosurgery (J Neurosurg) Vol. 75 Issue 6 Pg. 906-10 (Dec 1991) ISSN: 0022-3085 UNITED STATES |
PMID | 1941119 (Publication Type: Journal Article) |
American Institute for Hyperhidrosis claims to cure anxiety and palpitations with ETS
Migraine occurrence and trembling of the hands may improve.
(They also claim, that Copensatory Hyperhidorsis is) "tolerable by most patients and only 5% describe it as troublesome. Some patients say it improves with time."
http://www.handsweat.com/sideeff.html
There has been no clinical evaluation of the severity of the so called CS to this day. Surgeons who perform the surgery and profit from it claim it to be close to insignificant..that even improves with time. Other sources will state 90% of severe CS, and 25% disabling CS. Surely it can not be just a question of semantics when you have a 25% chance of being disabled after an elective surgery!
Doctors are unable to support their claims about the positive outcomes of the surgery. There has been no controlled trial to support their positive advertising, and it is left solely to the discretion of the surgeon to admit or deny the incidence and severity of the side-effects.
permanent sympathetic nerve damage and hyperthermia due to sympathectomy
www.rsdrx.com/crps_and_sympathectomy.htm
acute response to surgical denervation and abrupt release of sympathetic tone
Information on the long-term physiological sequelae is emerging rapidly. Preoperatively, in addition to abnormal sudomotor control, sympathetic cardiovascular regulation may be affected mildly in severe cases of hyperhidrosis. A blunted reflex bradycardia response to parasympathomimetic maneuvers such as Valsalva maneuver or cold water face immersion, as well as an increased heart rate response
to orthostatic stress, suggests a hyperfunctioning sympathetic discharge that is reversed after ETS.25,69 Because sympathetic cardiac accelerator fibers exit the spinal cord from segments T1 to T4, ETS is believed to simulate a mild physiological !-adrenergic blockade.70 This is because the heart rate at rest and during maximal exercise is lower 6 weeks postoperatively
DIAGNOSIS AND TREATMENT OF HYPERHIDROSIS, CONCISE REVIEW FOR CLINICIANS
Mayo Clin Proc. • May 2005;80(5):657-666
denervation supersensitivity of alpha receptors after sympathectomy
compensatory disease may not be immediate after sympathectomy
The main complications with sympathectomy include compensatory sweating, phantom sweating, gustatory sweating, Horner syndrome, and neuralgia.
Management of Hyperhidrosis
Aamir Haider, Nowell Solish and Nicholas J. Lowe
www.sweatclinicsofcanada.com/Book.pdf
This injures all the neurons at this level of the spinal cord, some of which may die, and may predispose the patient to spinal cord reorganization and severe compensatory hyperhidrosis
of palmar hyperhidrosis.
Mayo Clin Proc 2003;78:167-172. http://www.mayoclinic.org/medicalprofs/enlargeimage5096.html
Sensory nerves impair sympathetic reinnervation and recovery of smooth muscle function
http://www.ncbi.nlm.nih.gov/pubmed/1397180
Sympathectomy alters bone architecture
http://www.ncbi.nlm.nih.gov/pubmed/18449939
obliteration of the cervical sympathetic peripheral innervation impairs the capability to produce an induced febrile response.
reduction in hypothalamic dopamine after sympathectomy, which leads to an increase in serum prolactin level
http://ajpendo.physiology.org/content/293/5/E1224.full
"Again, patients admitted with any malignancy, cholecystectomy, thyroidectomy, renal disease, cardiac disease, sympathectomy, or vascular graft were eliminated as controls."
This article reviews the evidence that neuroleptics may increase the risk of breast cancer via their effects on prolactin secretion.
Paul M. Schyve; Francine Smithline; Herbert Y. Meltzer
Neuroleptic-induced Prolactin Level Elevation and Breast Cancer: An Emerging Clinical Issue
Arch Gen Psychiatry, Nov 1978; 35: 1291 - 1301.
(78), suggesting that normal heat defense is associated with decreased central dopamine, and
intraventricular haloperidol produces a coordinated heat-defense response (79). These reports refute a
unique or essential role for central dopamine antagonism in neuroleptic malignant syndrome hyperthermia
and provide additional evidence that state-dependent factors are important mediators of dopamine
antagonist effects.
There is substantial evidence to support the hypothesis that dysregulated sympathetic nervous system hyperactivity is responsible for most, if not all, features of neuroleptic malignant syndrome. A predisposition to more extreme sympathetic nervous system activation and/or dysfunction in response to emotional or psychological stress may constitute a trait vulnerability for neuroleptic malignant syndrome, which, when coupled with state variables such as acute psychic distress or dopamine receptor antagonism, produces the clinical syndrome of neuroleptic malignant syndrome. This hypothesis provides a more comprehensive explanation for existing clinical data than do the current alternatives.
http://ajp.psychiatryonline.org/cgi/content/full/156/2/169
dural blood flow decreased significantly in the cervical sympathectomy group
http://www.autonomicneuroscience.com/article/S1566-0702%2811%2900026-9/abstract
Effects of upper abdominal sympathectomy on gastric acid, serum gastrin, and catecholamines
http://www.ncbi.nlm.nih.gov/pubmed/6515311
Extreme caution is called for when considering surgical sympathectomy
control groups, and personal experience. Though it would appear logical (and has been
suggested) that surgical sympathectomy is indicated primarily for patients with confirmed
'sympathetic-dependent pain, other authors take the view that the treatment results are
not correlated to this. Eighteen percent of patients undergoing sympathectomy for
neuropathic pain experience compensatory hyperhidrosis and 25% experience neuropathic
complications.
Extreme caution is called for when considering surgical sympathectomy for pain control in
CRPS-I. The procedure should be conducted in the context of a trial in order to ascertain
the efficacy and potential risks.
Guideline
INITIATIVE:
Netherlands Society of Rehabilitation Specialists
Netherlands Society of Anaesthesiologists
WITH THE SUPPORT OF:
Institute for Healthcare Improvement CBO
www.cbo.nl/Downloads/341/rl_crps_eng_07.pdf
Decreased tanning response after video-assisted thoracoscopic sympathectomy
lumbar sympathectomy results in loss of ejaculation
During fever pyrogen is released from leucocytes and his agent causes the disturbed thermoregulation (Atkinson, 1960). For his response to occur, an intact efferent sympathetic system is requred because fever can be markedly reduced by bilateral sympathectomy in he cat (Pinkston, 1935). (p.193)
The autonomic nervous system: an introduction to basic and clinical concepts By Otto Appenzeller, Emilio Oribe, Elsevier Health Sciences, 1997 - Medical
significant change after sympathectomy: reduced sympathetic and increased vagal tone
http://www.sciencedirect.com/science/article/pii/S0167527399001011
Sympathectomy leads to a decrease in noradrenaline levels in the cerebral cortex
brain levels of norepinephrine were reduced significantly
EFFECT OF 6-HYDROXYDOPAMINE ON BRAIN NOREPINEPHRINE AND DOPAMINE: EVIDENCE FOR SELECTIVE DEGENERATION OF CATECHOLAMINE NEURONS
1 Departments of Psychiatry and Pharmacology and the Child Development Institute, University of North Carolina School of Medicine, Chapel Hill, North Carolina
After the intracisternal administration of 6-hydroxydopamine, brain levels of norepinephrine were reduced significantly with or without pargyline pretreatment. Depletion of dopamine in the central nervous system was found to be enhanced markedly by pargyline administration at higher dose levels of 6-hydroxydopamine. Brain serotonin concentrations were not altered. The effects of 6-hydroxydopamine were long-lasting with the depletion of brain amines persisting at 78 days. After norepinephrine-H3 intracisternally to animals treated with 6-hydroxydopamine, labeled norepinephrine uptake was diminished with a corresponding reduction of deaminated catechols and a marked increased in methylated amines. Tyrosine hydroxylase activity was found to be reduced in brainstem, caudate nucleus and whole brain in 6-hydroxydopamine-treated animals. Conversion of tyrosine-H3 to labeled norepinephrine and dopamine was also markedly diminished. The results support the view that 6-hydroxydopamine produces a "central sympathectomy" when introduced into cerebrospinal fluid.
Journal of Pharmacology And Experimental Therapeutics, Vol. 174, Issue 3, 413-420, 1970Copyright © 1970 by American Society for Pharmacology and Experimental Therapeutics
sympathectomy impairing adrenergic transmission
Antônio Tadeu de Souza FaleirosI; Francisco Humberto de Abreu MaffeiII; Luiz Antonio de Lima ResendeIII
IServices of Neurosurgery, Botucatu School of Medicine, São Paulo State University (UNESP), Botucatu, SP, Brazil
IIVascular Surgery, Botucatu School of Medicine, São Paulo State University (UNESP), Botucatu, SP, Brazil
IIINeurology, Botucatu School of Medicine, São Paulo State University (UNESP), Botucatu, SP, Brazil
marked changes in brain NE following sympathectomy
Biochemical and functional evaluation of the sympathectomy produced by the administration of guanethidine to newborn rats
EM Johnson , E Cantor and JR Douglas
The administration of guanethidine to newborn rats has been shown by morphological criteria to destroy sympathetic neurons. Newborn rats were injected with guanethidine (50-100 mg/kg/day for 20 days). Upon maturation (at 10 weeks old), the degree of destruction of the sympathetic nervous system (sympathectomy) was assessed. Marked decreases (80-98%) in the norepinephrine concentration in several tissues (heart, spleen, intestine, mesentery, kidney, uterus, vas deferens) were observed in the guanethidine-treated rats when compared to saline-treated controls. No changes were observed in the epinephrine concentration in the adrenals or in the norepinephrine levels in whole brain. Analysis of brain areas showed no change in the norepinephrine levels in brain stem and cerebrum and a small (18%) decrease in the cerebellum. Stimulation of the sympathetic vasomotor outflow in the pithed rat preparation produced almost no response in guanethidine- treated animals. Periarterial nerve stimulation of the isolated perfused kidney preparation also produced essentially no response in guanethidine-treated animals. Isolated intestinal preparations from guanethidine-treated animals responded to nerve stimulation with contractions rather than relaxation as seen in preparations from control animals. Isolated vas deferens preparations responded normally to nerve stimulation despite a 95% decrease in tissue norepinephrine concentration. These data indicate that administration of guanethidine to newborn rats produces a more complete peripheral sympathectomy, especially of the vasculature, than immunosympathectomy or neonatal administration of 6-hydroxydopamine and does so with no significant effect on central noradrenergic neurons.
Volume 193, Issue 2, pp. 503-512, 05/01/1975
Copyright © 1975 by American Society for Pharmacology and Experimental Therapeutics
the adrenergic system in regulation of the metabolism of the retina
Stefan M. Pojda1 and Ryszard Brus2
(1) | Department of Ophthalmology, Silesian Academy of Medicine, Francuska str. 20/24, 40-027 Katowice, Poland |
(2) | Department of Pharmacology, Silesian Academy of Medicine, Zabrze 8, Poland |
Received: 16 April 1976
Heightened emotions cause experiences to crystallize into lasting and vivid memories
Emotional memory.(NEUROSCIENCE)(effect of Norepinephrine to memory)(Brief article)
- From:
- Science News
- Date:
- October 20, 2007
- Author:
- Barry, P. | Copyright information COPYRIGHT 2007 Science Service, Inc. This material is published under license from the publisher through the Gale Group, Farmington Hills, Michigan. All inquiries regarding rights should be directed to the Gale Group.
Where were you on Sept. 11, 20017 Or when the shuttle Challenger exploded in 19867 Heightened emotions cause experiences to crystallize into lasting and vivid memories. This boost in memory formation is due in part to the stress hormone norepinephrine, but scientists haven't understood how the hormone causes this effect.
Now researchers have uncovered molecular changes triggered by norepinephrine that help nerve cells form new memories.
A team led by Roberto Malinow of Cold Spring Harbor Laboratory in New York traced the hormone's effects to a receptor molecule called glutamate receptor 1 (G1uR1) on the surfaces of nerve cells. Through G1uR1 and similar receptors, ... http://www.highbeam.com/doc/1G1-170372501.html
brain norepinephrine turnover, and memory and the need for Power
David C. McClelland1 , J. Anderson Maddocks1 and Dan P. McAdams1, 2
(1) | Department of Psychology and Social Relations, Harvard University, 33 Kirkland Street, 02138 Cambridge, Massachusetts |
(2) | Present address: Loyola University of Chicago, USA |
The need for power, brain norepinephrine turnover, and memory
Journal | Motivation and Emotion |
Publisher | Springer Netherlands |
ISSN | 0146-7239 (Print) 1573-6644 (Online) |
Issue | Volume 9, Number 1 / March, 1985 |
DOI | 10.1007/BF00991546 |
Pages | 1-10 |
Subject Collection | Behavioral Science |
SpringerLink Date | Monday, January 10, 2005 |
Norepinephrine
Doze said the adrenergic system — one of the essential neurochemical systems in the brain — synthesizes and controls the release of the neurotransmitter norepinephrine (also known as noradrenalin).
Norepinephrine works in both the central and peripheral nervous systems. It’s responsible for many critical functions, but in this context, its key functions in the central nervous system include sleep, emotions, learning, and memory.Probing the deepest levels of brain chemistry to uncover clues to memory loss
By Juan Miguel PedrazaA neurotransmitter involved in emotional arousal enhances learning
Do you remember the song that was playing during your first kiss? Both positive and negative emotions influence learning and memory but researchers have not determined the mechanism. Now Hu et al. report that the neurotransmitter norepinephrine regulates glutamate receptor trafficking in a recent article in Cell.
Axon terminals containing norepinephrine synapse in the hippocampus and amygdala, which are important in emotional memory. In the hippocampus, norepinephrine reduces the threshold for long-term potentiation (LTP), which is thought to be a substrate of memory. Norepinephrine acts at -adrenergic receptors, where it activates cAMP-dependent protein kinase (PKA) and calcium/calmodulin-dependent protein kinase II (CaMKII). These kinases phosphorylate serines 845 and 831, respectively, in the AMPA glutamate receptor type 1 (GluR1). The authors proposed that norepinephrine regulates learning by phosphorylating AMPA receptors.
Hu, H. et al. Emotion enhances learning via norepinephrine regulation of AMPA-receptor trafficking. Cell 131, 160–173 (2007). | Article | PubMed |
Emotional intelligence
Neuroscience Gateway (October 2007) | doi:10.1038/aba1787The excitatory actions of epinephrine were not observed
Epinephrine administration increases neural impulses propagated along the vagus nerve: Role of peripheral β-adrenergic receptors
T. Miyashita and C.L. Williams
Received 9 June 2005;
arousal related hormone affects memory processing
Epinephrine administration increases neural impulses propagated along the vagus nerve: Role of peripheral β-adrenergic receptors
Received 9 June 2005;
The role of norepinephrine in spatial reference and spatial working memory
The adrenergic system (utilizing norepinephrine, NE, as a neurotransmitter) is implicated in hippocampus-based learning and memory, in addition to its well known peripheral actions mediated by the sympathetic nervous system.
Michael J. Gertner, University of Pennsylvania
Steven A. Thomas, University of Pennsylvania
http://repository.upenn.edu/curej/18/
Norepinephrine Important In Retrieving Memories
Source: U. Of Pennsylvania Medical Center
Date: 2 April 2004
In addition, beta-blockers, which are used to treat heart failure and hypertension (among other ailments) block the same norepinephrine receptors important for memory retrieval. Therefore, when treating heart disease, the use of beta blockers that do not cross into the brain may help to avoid memory-related side effects, suggest the researchers.
The findings of this research appear in the April 2 issue of Cell.
Causes of Orthostatic Hypotension
Neurologic (involving autonomic dysfunction) -
Surgical sympathectomy
http://www.merck.com/mmpe/sec07/ch069/ch069d.html
NE levels and Posttraumatic Stress Disorder
Thomas D. Geracioti, Jr., M.D.
Dewleen G. Baker, M.D.
Nosakhare N. Ekhator, M.S.
Scott A. West, M.D.
Kelly K. Hill, M.D.
Ann B. Bruce, M.D.
Dennis Schmidt, Ph.D.
Barbara Rounds-Kugler, R.N.
Rachel Yehuda, Ph.D.
Paul E. Keck, Jr., M.D.
John W. Kasckow, M.D., Ph.D.
Objective: Despite evidence of hyperresponsive peripheral and central nervous system (CNS) noradrenergic activity in posttraumatic stress disorder (PTSD), direct measures of CNS norepinephrine in PTSD have been lacking. The goal of this study was to determine serial CSF norepinephrine levels in patients with PTSD.
Method: CSF samples were obtained serially over a 6-hour period in 11 male combat veterans with chronic PTSD and eight healthy men through an indwelling subarachnoid catheter. Thus the authors were able to determine hourly CSF norepinephrine concentrations under base-
line (unstressed) conditions. Severity of the patients’ PTSD symptoms was assessed with the Clinician-Administered PTSD Scale.
Results: CSF norepinephrine concentrations were significantly higher in the men
with PTSD than in the healthy men. Moreover, CSF norepinephrine levels strongly and
positively correlated with the severity of PTSD symptoms. Plasma norepinephrine concentrations showed no significant relationship with the severity of PTSD symptoms.
Conclusions: These findings reveal the presence of greater CNS noradrenergic activity under baseline conditions in patients with chronic PTSD than in healthy subjects and directly link this pathophysiologic observation with the severity of the clinical posttraumatic stress syndrome.
(Am J Psychiatry 2001; 158:1227–1230)
Alterations in T and B cell proliferation and differentiation in vitro following chemical sympathectomy
reduced antibody responses to T-dependent antigens
VOL. 31, NOS. 5 & 6, 2000 JOURNAL OF MEDICINE
JOURNAL OF MEDICINE
Copyright © 2000 by
PJD Publications Limited
The hepatic sympathetic nerve
The hepatic sympathetic nerve plays a critical role in preventing Fas induced liver injury in mice
Y Chida1, N Sudo1, A Takaki2, C Kubo1 1 Department of Psychosomatic Medicine, Graduate School of Medical Sciences, Kyushu University, Higashi-ku, Fukuoka, Japan
2 Department of Integrative Physiology, Graduate School of Medical Sciences, Kyushu University, Higashi-ku, Fukuoka, Japan
Dr Y Chida
Department of Psychosomatic Medicine, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
The sympathoadrenal system is one of the major pathways mediating physiological responses in the organism
Levels of plasma (p-) noradrenaline (NA), the sympathetic neurotransmitter, have been used to indicate activity of the neuronal sympathoadrenal component, while adrenaline (Adr) levels indicate activity of the hormonal adrenomedullary component of the sympathoadrenal system (Christensen 1991, Goldstein 1995, Christensen & Norsk 2000). Based upon the absence of an arterio-venous increase in p-DOPA concentration in sympathectomized limbs and a decrease in p-DOPA after inhibition of tyrosine hydroxylase (TH) in dogs, it was concluded that DOPA can pass across sympathetic neuronal membranes to reach the general circulation and furthermore, that p-DOPA may be related to regional rate of tyrosine hydroxylation (Goldstein et al 1987a). P-DOPA only demonstrated minimal changes during stimuli that produced significant changes in p-NA. Due to partly parallel changes of p-NA and p-DOPA, however, it was believed that p-DOPA reflect the rate of catecholamine synthesis and that p-DOPA was a simple and direct index of TH activity in vivo (Eisenhofer et al 1988, Goldstein & Eisenhofer 1988, Garty et al 1989b). It was inferred that p-DOPA levels may be an index of sympathetic activity.
Department of Internal Medicine and Endocrinology, Herlev University Hospital, Herlev.
Correspondence: Ebbe Eldrup, Bolbrovænge 29, DK-2960 Rungsted Kyst.