Document Detail

An analysis of the negative inotropic action of somatostatin.
MedLine Citation:
PMID:  465878     Owner:  NLM     Status:  MEDLINE    
1 Somatostatin (SS) was evaluated as a chronotropic and inotropic agent in isolated spontaneously beating auricles of rats, rabbits and guinea-pigs.2 SS was completely inactive in rat and rabbit auricles but exerted a dose-dependent, negative inotropic effect in guinea-pig auricles in concentrations between 1.5 x 10(-8) to 1.2 x 10(-6) M.3 The negative inotropic effect of SS (6.0 x 10(-8) and 3.0 x 10(-7) M) was not inhibited by a mixture of antagonists containing practolol (7.9 x 10(-6) M), phentolamine (3.5 x 10(-7) M), methysergide (2.8 x 10(-7) M), diphenhydramine (3.9 x 10(-5) M), cimetidine (4.0 x 10(-5) M) atropine (3.4 x 10(-7) M) and indomethacin (1.4 x 10(-5) M).4 The negative inotropic effect of SS was greatly potentiated by reduction in the Ca(2+) concentration of the medium from 5.0 to 1.25 mM.5 On a molar basis, SS was equipotent with acetylcholine (ACh) as a negative inotropic agent in the guinea-pig auricles.6 SS (6.0 x 10(-8) and 6.0 x 10(-7) M) was found to inhibit selectively the positive inotropic action of neurotensin (NT) in guinea-pig but not in rat auricles.7 The inhibitory action of SS against NT was independent of its negative inotropic action.8 These results suggest that SS produces its negative inotropic action by interacting with specific receptors presumably located in the cell membrane of guinea-pig atria. The interaction between SS and its receptor may cause a decreased Ca(2+) diffusion and/or transport into the atrial cells. The physiological and pharmacological significance of these results is discussed.
R Quirion; D Regoli; F Rioux; S St-Pierre
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Publication Detail:
Type:  Comparative Study; Journal Article    
Journal Detail:
Title:  British journal of pharmacology     Volume:  66     ISSN:  0007-1188     ISO Abbreviation:  Br. J. Pharmacol.     Publication Date:  1979 Jun 
Date Detail:
Created Date:  1979-10-26     Completed Date:  1979-10-26     Revised Date:  2010-09-02    
Medline Journal Info:
Nlm Unique ID:  7502536     Medline TA:  Br J Pharmacol     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  251-7     Citation Subset:  IM    
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MeSH Terms
Acetylcholine / pharmacology
Atropine / pharmacology
Calcium / pharmacology
Cimetidine / pharmacology
Diphenhydramine / pharmacology
Guinea Pigs
Indomethacin / pharmacology
Methysergide / pharmacology
Myocardial Contraction / drug effects*
Phentolamine / pharmacology
Practolol / pharmacology
Somatostatin / pharmacology*
Reg. No./Substance:
361-37-5/Methysergide; 50-60-2/Phentolamine; 51-55-8/Atropine; 51-84-3/Acetylcholine; 51110-01-1/Somatostatin; 51481-61-9/Cimetidine; 53-86-1/Indomethacin; 58-73-1/Diphenhydramine; 6673-35-4/Practolol; 7440-70-2/Calcium

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

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