Document Detail


Nicotine-induced relaxation in isolated canine cerebral arteries.
MedLine Citation:
PMID:  1142095     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Nicotine in concentrations ranging from 5 times 10- minus 6 to 10- minus 4 M caused a transient relaxation in strips of isolated canine basilar, middle cerebral and posterior cerebral arteries contracted with prostaglandin F2a (PGF). Transmural neural stimulation did not produce changes in the tension of these arteries. Tyramine contracted the arterial strips. Relaxation induced by nicotine was markedly attenuated by hexamethonium (10- minus 5 M), cocaine (10- minus 5M), bretylium (2 times 10- minus 5 M), sotalol (5 times 10- minus 5 M), propranolol (10- minus 6 M) and removal of Ca-++ from the bathing media. Relaxation was not significantly influenced by atropine, physostigmine, ouabain, tetrodotoxin, aminophylline and sotalol (10- minus 5 M). In cerebral arterial strips, the addition of K-+ also elicited a transient relaxation which was abolished by treatment with ouabain but not with other blocking agents. In mesenteric arterial strips, nicotine caused a transient contraction as did transmural stimulation. The nicotine-induced contraction was markedly attenuated or completely abolished by hexamethonium, cocaine, bretylium and phentolamine and also high concentration of sotalol (5 times 10- minus 5 M), and propranolol. Tetrodotoxin did not affect the contractile response to nicotine but did abolish the response to transmural stimulation. It is strongly suggested that relaxation induced by nicotine in cerebral arterial strips is the result of a specific action on nicotinic receptors as is the contraction observed in mesenteric arteries. It appears that beta adrenergic and cholinergic mechanisms do not play major roles in the genesis of nicotine-induced relaxation nor does it appear that an electrogenic Na-+ pump mechanism is involved.
Authors:
N Toda
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Publication Detail:
Type:  In Vitro; Journal Article    
Journal Detail:
Title:  The Journal of pharmacology and experimental therapeutics     Volume:  193     ISSN:  0022-3565     ISO Abbreviation:  J. Pharmacol. Exp. Ther.     Publication Date:  1975 May 
Date Detail:
Created Date:  1975-10-10     Completed Date:  1975-10-10     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0376362     Medline TA:  J Pharmacol Exp Ther     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  376-84     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Animals
Atropine / pharmacology
Bretylium Compounds / pharmacology
Cerebral Arteries / drug effects*,  physiology
Cocaine / pharmacology
Dogs
Electric Stimulation
Female
Hexamethonium Compounds / pharmacology
Male
Mesenteric Arteries / drug effects,  physiology
Muscle Contraction / drug effects*
Nicotine / pharmacology*
Ouabain / pharmacology
Potassium / pharmacology
Propranolol / pharmacology
Prostaglandins F / pharmacology
Sotalol / pharmacology
Sympathetic Nervous System / physiology
Chemical
Reg. No./Substance:
0/Bretylium Compounds; 0/Hexamethonium Compounds; 0/Prostaglandins F; 3930-20-9/Sotalol; 50-36-2/Cocaine; 51-55-8/Atropine; 525-66-6/Propranolol; 54-11-5/Nicotine; 630-60-4/Ouabain; 7440-09-7/Potassium

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


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