Document Detail


Effect of pressure on the release of endogenous dopamine from rat striatum and the role of sodium-calcium exchange.
MedLine Citation:
PMID:  1536059     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Exposure to environmental pressures in excess of 20 atm abs can precipitate a hyperexcitability state known as high pressure neurologic syndrome (HPNS). Little is known about the underlying neurochemical basis of this syndrome. An in vitro model of the synthesis and release of endogenous dopamine (DA) from rat striatal slices has been used to examine the mechanism underlying the effects of high pressures of He. He at 100 atm abs produced changes in DA release which were strikingly similar to those of the cardiac glycoside, ouabain. Neither pressure nor ouabain (1-10 microM) had any significant effects on the spontaneous (nonevoked) release of DA or its metabolite 3,4-dihydroxyphenylacetic acid, but both pressure and ouabain significantly enhanced the stimulated release of DA which was evoked by a 6-min exposure to 35 mM KCl (P less than 0.05 and P less than 0.001). In both cases, this effect was dependent on the presence of extracellular Ca2+. Augmentation of evoked DA release by both ouabain and He pressure was reversed (P less than 0.05) by 3,4-dichlorobenzamil, a selective antagonist of the membrane Na+/Ca2+ exchange mechanism. The results suggest that pressure exerts its effects on DA release by increasing intracellular-free Ca2+ exchange after pressure-inhibition of the activity of the membrane Na,K-ATPase.
Authors:
M L Paul; R B Philp
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Undersea biomedical research     Volume:  19     ISSN:  0093-5387     ISO Abbreviation:  Undersea Biomed Res     Publication Date:  1992 Jan 
Date Detail:
Created Date:  1992-03-23     Completed Date:  1992-03-23     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0421514     Medline TA:  Undersea Biomed Res     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1-12     Citation Subset:  IM; S    
Affiliation:
Department of Pharmacology and Toxicology, University of Western Ontario, London, Canada.
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MeSH Terms
Descriptor/Qualifier:
3,4-Dihydroxyphenylacetic Acid / metabolism
Amiloride / analogs & derivatives,  pharmacology
Animals
Calcium / metabolism*
Corpus Striatum / metabolism*
Dopamine / secretion*
Helium / antagonists & inhibitors,  pharmacology*
High Pressure Neurological Syndrome / metabolism*
Male
Ouabain / antagonists & inhibitors,  pharmacology*
Potassium / metabolism
Rats
Rats, Inbred Strains
Chemical
Reg. No./Substance:
102-32-9/3,4-Dihydroxyphenylacetic Acid; 1166-01-4/3',4'-dichlorobenzamil; 2609-46-3/Amiloride; 630-60-4/Ouabain; 7440-09-7/Potassium; 7440-59-7/Helium; 7440-70-2/Calcium

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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