Temperature-dependent postextrasystolic potentiation and Ca(2+) recirculation fraction in canine hearts

American Journal of Physiology. Heart and Circulatory Physiology
J MizunoH Suga


We have found that cardiac temperature proportionally changes O(2) cost of contractility, defined as O(2) consumption for myocardial total Ca(2+) handling normalized to contractility in terms of the end-systolic pressure-volume ratio (maximal elastance, E(max)), in the canine left ventricle (temperature sensitivity, Q(10) = 2). We have separately found that a decrease in the recirculation fraction (RF) of Ca(2+) within myocardial cells underlies an increased O(2) cost of E(max) in stunned hearts. We therefore hypothesized that a similar change in RF would underlie the Q(10) of O(2) cost of E(max). We tested this hypothesis by analyzing RF calculated from an exponential decay component of the transiently alternating postextrasystolic potentiation in the canine left ventricle. RF decreased from 0.7 to 0.5 as cardiac temperature increased from 33 to 38 degrees C with Q(10) of 0.5, reciprocal to that of O(2) cost of E(max). We conclude that Q(10) of ATP-consuming reactions involved in Ca(2+) handling and E(max) response to it could reasonably account for the reciprocal Q(10) of RF and O(2) cost of E(max).


Apr 1, 1990·Physiological Reviews·H Suga
Aug 1, 1990·The American Journal of Physiology·J A Rall, R C Woledge
Apr 1, 1990·Archives of Biochemistry and Biophysics·P DebettoS Luciani
Dec 21, 1985·Journal of Theoretical Biology·D AdlerY Mahler
Aug 1, 1982·Acta Physiologica Scandinavica·B Wohlfart
Jan 1, 1982·Annual Review of Physiology·M Tada, A M Katz
Jan 1, 1982·Pharmacology & Therapeutics·B Wohlfart, M I Noble
Jun 1, 1980·The Journal of Physiology·D A Eisner, W J Lederer
Dec 1, 1993·The Journal of Physiology·T PowellR Z Kozlowski
Apr 15, 1996·Annals of the New York Academy of Sciences·D M BersR A Bassani
Jan 22, 1998·The American Journal of Physiology·T MikaneH Suga
Jun 24, 1998·Pflügers Archiv : European journal of physiology·T J Allen, G Mikala
Oct 30, 1999·Heart and Vessels·J MizunoH Suga
Apr 25, 2000·American Journal of Physiology. Heart and Circulatory Physiology·S LeeH Suga
Jul 19, 2000·American Journal of Physiology. Heart and Circulatory Physiology·J ShimizuH Suga
Nov 22, 2000·American Journal of Physiology. Heart and Circulatory Physiology·A SaekiH Suga
Dec 20, 2000·The Japanese Journal of Physiology·M MaesakoH Suga

Related Concepts

Myocardial Contraction
In Silico
Left Ventricular Structure
Left Ventricular Function
Body Surface Area Formula for Dogs
Sarcoplasmic Reticulum
Cardiac Conduction System

Related Feeds

Cardiac Conduction System

The cardiac conduction system is a specialized tract of myocardial cells responsible for maintaining normal cardiac rhythm. Discover the latest research on the cardiac conduction system here.