Document Detail

Prevention of hypertension is associated with reduced susceptibility to histamine-induced arrhythmias in SHR.
MedLine Citation:
PMID:  2970857     Owner:  NLM     Status:  MEDLINE    
Two groups of spontaneously hypertensive rats (SHR) were treated with alpha-methyldopa (2.5 g/L in drinking water) for 12-17 weeks. One group was treated during the normal time course for development of hypertension and myocardial hypertrophy (beginning at age 4 weeks), while the other was treated after stabilization of hypertension/hypertrophy (21 weeks). Appropriate age-matched controls (WKY strain) also were treated. Intracellular microelectrodes were used to monitor action potential configuration, automaticity, and the incidence of arrhythmias (including delayed afterdepolarizations and repetitive tachyarrhythmias) in isolated left ventricles from each group. The younger rats did not develop hypertension of left ventricular hypertrophy; susceptibility of isolated left ventricles to histamine-induced (10(-5) M) arrhythmogenesis was significantly reduced. The older rats showed decreased blood pressure, although not to normal levels; further left ventricular hypertrophy was prevented, though the existing enlargement did not regress. These hearts were as susceptible to the development of histamine-induced arrhythmias as were hearts of untreated SHR. Enhanced susceptibility to arrhythmias in hypertrophied hearts reflects a preventable alteration of the myocardial cell membrane that occurs during the course of blood pressure elevation. This change may be associated with defective sarcolemmal calcium transport in hypertrophied myocardium.
J S Cameron; L J Antonik
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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:  American journal of hypertension     Volume:  1     ISSN:  0895-7061     ISO Abbreviation:  Am. J. Hypertens.     Publication Date:  1988 Jul 
Date Detail:
Created Date:  1988-10-19     Completed Date:  1988-10-19     Revised Date:  2009-02-24    
Medline Journal Info:
Nlm Unique ID:  8803676     Medline TA:  Am J Hypertens     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  34S-37S     Citation Subset:  IM    
Department of Biological Sciences, Wellesley College, Massachusetts 02181.
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MeSH Terms
Arrhythmias, Cardiac / chemically induced*
Blood Pressure / drug effects
Cardiomegaly / physiopathology,  prevention & control
Disease Susceptibility
Histamine / pharmacology*
Hypertension / physiopathology,  prevention & control*
Rats, Inbred SHR
Rats, Inbred WKY
Grant Support
Reg. No./Substance:

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

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