Document Detail

Alterations of cardiac alpha- and beta-adrenoceptors and inotropic responsiveness in hypertensive transgenic rats harbouring the mouse renin gene (TGR(mREN2)27).
MedLine Citation:
PMID:  7795578     Owner:  NLM     Status:  MEDLINE    
In the present study, we investigated the alpha- and beta-adrenoceptor-mediated effects on myocardial force of contraction (using phenylephrine in the presence of propranolol and isoprenaline) and receptor densities (binding studies using [3H]-prazosin and [125I]-iodocyanopindolol) in hypertensive transgenic rats (TGR(mREN2)27) and age-matched Sprague-Dawley rats (SP) as controls. In TGR(mREN2)27 the positive inotropic effects of isoprenaline and phenylephrine were reduced, while the effect of Ca2+ was unchanged. The EC50-values did not differ in both groups. A down-regulation of the beta-adrenoceptors was observed in the hypertrophied left ventricles of transgenic rats, which is postulated to be involved in the reduced beta-adrenoceptor-mediated positive inotropic effect. The alpha-adrenoceptor density was increased, which could represent a compensatory mechanism for the impaired effectiveness of the beta-adrenergic pathway. However, since the effect of alpha-adrenoceptor agonist is not enhanced but even reduced, an uncoupling of alpha-adrenoceptors from post receptor events could play a role in the observed effects.
H Tawfik-Schlieper; M Moll; B Schmid; R H Schwinger; M Paul; D Ganten; M Böhm
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Clinical and experimental hypertension (New York, N.Y. : 1993)     Volume:  17     ISSN:  1064-1963     ISO Abbreviation:  Clin. Exp. Hypertens.     Publication Date:  1995 May 
Date Detail:
Created Date:  1995-07-28     Completed Date:  1995-07-28     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  9305929     Medline TA:  Clin Exp Hypertens     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  631-48     Citation Subset:  IM    
Klinik III für Innere Medizin der Universität zu Köln, Germany.
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MeSH Terms
Animals, Genetically Modified
Hypertension / genetics,  physiopathology*
Isoproterenol / pharmacology
Myocardial Contraction / drug effects
Myocardium / metabolism*,  pathology
Organ Size
Phenylephrine / pharmacology
Radioligand Assay
Rats, Sprague-Dawley
Receptors, Adrenergic, alpha / metabolism*
Receptors, Adrenergic, beta / metabolism*
Renin / genetics*
Reg. No./Substance:
0/Receptors, Adrenergic, alpha; 0/Receptors, Adrenergic, beta; 59-42-7/Phenylephrine; 7683-59-2/Isoproterenol; EC

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