Document Detail

Restoration of action potential duration and transient outward current by regression of left ventricular hypertrophy.
MedLine Citation:
PMID:  9201619     Owner:  NLM     Status:  MEDLINE    
The presence of left ventricular hypertrophy (LVH) is associated with an increased incidence of arrhythmias. Our previous study on hypertrophied rat hearts has demonstrated that regression of LVH prevents ischemia-induced lethal arrhythmias. To elucidate the underlying mechanism of the reduced incidence of arrhythmias in regression of LVH, we examined electrophysiological properties of both hypertrophied and regressed left ventricular cells. Hearts from spontaneously hypertensive rats (SHR) were used as LVH, and those from Wistar-Kyoto rats (WKY) served as control. SHR with regression of LVH (REG) was produced by captopril treatment. Action potentials and membrane currents of subendocardial left ventricular cells were compared by the whole-cell patch-clamp techniques. Although the membrane capacitance of SHR cells was significantly greater than that of WKY cells, that of REG cells was normalized to the control level. Prolonged action potential duration (APD) and reduced density of transient outward current (ito) in SHR cells was normalized by LVH regression (APD at 75% repolarization (ms) and ito density at +60 mV (pA/pF): WKY 36.1 +/- 4.2, 11.9 +/- 1.3, SHR 73.1 +/- 12.9, 5.2 +/- 0.7, REG 29.5 +/- 3.9, 10.4 +/- 2.0, P = 0.015, P = 0.001 v WKY). No significant differences were observed in the densities of steady-state outward current, inward rectifier current, and L-type Ca2+ current. The restoration of ito density by regression of LVH could normalize the prolonged APD in hypertensive LVH, which may be causally related to the reduced incidence of arrhythmias in LVH regression.
H Yokoshiki; T Kohya; F Tomita; N Tohse; H Nakaya; M Kanno; A Kitabatake
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Journal of molecular and cellular cardiology     Volume:  29     ISSN:  0022-2828     ISO Abbreviation:  J. Mol. Cell. Cardiol.     Publication Date:  1997 May 
Date Detail:
Created Date:  1997-09-24     Completed Date:  1997-09-24     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  0262322     Medline TA:  J Mol Cell Cardiol     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  1331-9     Citation Subset:  IM    
Department of Cardiovascular Medicine, Hokkaido University School of Medicine, Japan.
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MeSH Terms
Action Potentials
Antihypertensive Agents / therapeutic use
Blood Pressure
Calcium / metabolism
Captopril / therapeutic use
Heart / physiology,  physiopathology
Heart Ventricles / cytology,  physiopathology
Hypertrophy, Left Ventricular / drug therapy,  physiopathology*
Organ Size
Rats, Inbred SHR
Rats, Inbred WKY
Ventricular Function*
Reg. No./Substance:
0/Antihypertensive Agents; 62571-86-2/Captopril; 7440-70-2/Calcium

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