Document Detail


Overexpression of alpha1B-adrenergic receptor induces left ventricular dysfunction in the absence of hypertrophy.
MedLine Citation:
PMID:  9746484     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The stimulation of cardiac alpha1-adrenergic receptors (AR) modulates the heart's inotropic response and plays a role in the induction of cardiomyocyte hypertrophy. We have analyzed transgenic mouse lines overexpressing a wild-type alpha1B-AR specifically in the heart. Basal level systolic and diastolic left ventricular (LV) contractile function was depressed both in the anesthetized closed-chest mouse and the perfused working-heart preparation. Intrinsic LV function was further characterized under controlled preload and afterload conditions using the perfusion model. Contractile parameters were restored by chronic treatment with the alpha-AR antagonist prazosin. In ventricular function curves, the load-dependent force increases (length-tension effects) remained intact, although the transgenic curve was shifted to lower levels. The basal level contractile deficits were paralleled by a decrease in calcium transients in isolated LV cardiomyocytes. LV function comparable to controls was restored by isoproterenol stimulation. The physiological changes occurred in the absence of cardiomyocyte hypertrophy. This transgenic model will be useful for studying the potential role of alpha1-AR in cardiac contractility and hypertrophy.
Authors:
I L Grupp; J N Lorenz; R A Walsh; G P Boivin; H Rindt
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Publication Detail:
Type:  In Vitro; Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The American journal of physiology     Volume:  275     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1998 Oct 
Date Detail:
Created Date:  1998-11-19     Completed Date:  1998-11-19     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0370511     Medline TA:  Am J Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  H1338-50     Citation Subset:  IM    
Affiliation:
Department of Pharmacology and Cell Biophysics, University of Cincinnati, Cincinnati, Ohio 45267, USA.
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MeSH Terms
Descriptor/Qualifier:
Animals
Blood Pressure / drug effects
Calcium / metabolism
Cardiomegaly / physiopathology*
Cells, Cultured
Heart / physiology,  physiopathology*
Heart Rate / drug effects
Isoproterenol / pharmacology
Mice
Mice, Inbred C57BL
Mice, Inbred Strains
Mice, Transgenic
Myocardial Contraction / drug effects,  physiology*
Myocardium / metabolism,  ultrastructure
Prazosin / pharmacology
Receptors, Adrenergic, alpha-1 / antagonists & inhibitors,  genetics,  physiology*
Regression Analysis
Ventricular Dysfunction, Left / physiopathology*
Ventricular Function, Left / drug effects,  physiology
Chemical
Reg. No./Substance:
0/Receptors, Adrenergic, alpha-1; 0/adrenergic receptor alpha(1b); 19216-56-9/Prazosin; 7440-70-2/Calcium; 7683-59-2/Isoproterenol

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


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