Document Detail


Conservation of L-type Ca2+ current characteristics in endo- and epicardial myocytes from rat left ventricle with pressure-induced hypertrophy.
MedLine Citation:
PMID:  11810209     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Cardiac hypertrophy alters the regional distribution of action potential duration by affecting the magnitude and kinetics of underlying ionic currents. In the present study, the effect of pressure-induced cardiac hypertrophy on the magnitude and kinetics of the L-type Ca2+ current ( I(CaL)) was investigated in endo- and epicardial myocytes of the rat left ventricular free wall. Cardiac hypertrophy was induced by stenosis of the ascending aorta (AS), which led to a pressure difference between the left ventricular peak pressure and the peripheral systolic blood pressure of 84+/-6 mmHg ( n=5, P<0.0001). Sham-operated animals served as controls ( n=7). I(CaL) was investigated using the whole-cell patch-clamp technique. The magnitude of I(CaL) as well as its inactivation, steady-state activation, steady-state inactivation and recovery from inactivation were similar in endo- and epicardial myocytes of sham-operated rats. In myocytes isolated from AS animals, I(CaL) magnitude was significantly greater than in sham-operated animals (2407+/-127 pA, n=42 versus 1904+/-102 pA, n=33; P<0.01). This difference disappeared, however, when I(CaL) was normalized to cell capacitance. The kinetic properties of I(CaL) were unaffected by AS in both endo- and epicardial myocytes. In conclusion, in pressure-induced cardiac hypertrophy the density and kinetics of I(CaL) are preserved. This suggests that an additional insertion or recruitment of channels normally underlying I(CaL) into the cell membrane compensates for the increased cell size associated with hypertrophy.
Authors:
Tilmann Volk; Heimo Ehmke
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Publication Detail:
Type:  Journal Article     Date:  2001-10-09
Journal Detail:
Title:  Pflügers Archiv : European journal of physiology     Volume:  443     ISSN:  0031-6768     ISO Abbreviation:  Pflugers Arch.     Publication Date:  2002 Jan 
Date Detail:
Created Date:  2002-01-25     Completed Date:  2002-04-24     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  0154720     Medline TA:  Pflugers Arch     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  399-404     Citation Subset:  IM    
Affiliation:
Institut für Physiologie, Universität Hamburg, Hamburg, Germany. volk@uke.uni-hamburg.de
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MeSH Terms
Descriptor/Qualifier:
Animals
Aorta / pathology
Aortic Valve Stenosis / pathology
Blood Pressure / physiology
Calcium / metabolism
Calcium Channels, L-Type / physiology*
Endocardium / pathology
Female
Heart Ventricles / pathology,  physiopathology
Hypertrophy, Left Ventricular / pathology,  physiopathology*
Muscle Fibers, Skeletal / pathology,  physiology*
Pericardium / pathology
Rats
Rats, Sprague-Dawley
Sarcoplasmic Reticulum / metabolism
Ventricular Pressure / physiology
Chemical
Reg. No./Substance:
0/Calcium Channels, L-Type; 7440-70-2/Calcium

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


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