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Experimental analysis of the calcium source for cardiac excitation-contraction coupling in hibernator Citellus dauricus

Wang Shiqiang, Feng Qiang, Zhou Zengquan

College of Life Sciences, Peking University. Beijing 100871

Abstract

The force-interval and force-frequency relationships and the effects of Cd~(2+) and ryanodine on the myocardial action potential and contraction were compared between hibernating(HGS)and active(AGS) ground squirrels Citellus dauricus. Raising the driving frequency caused a negative inotropic effect in the AGS group, but a biphasic change with an increase of the peak force followed by a decrease in the HGS group. The contraction in HGS group exhibited a more pronounced post-interval potentiation, and was more significantly modulated by the driving frequency. HGS animals displaged action potentials of shorter early-stage duration and stronger contractions of shorter time course in comparison with the AGS animals. Both the action potential and the contraction of HGS group were less affected by Cd~(2+), but the contraction was more significantly inhibited by ryanodine than that of the AGS group.

Key words: Hibernation;Cardiac excitation-contrsction coupling;Action potential;Force-frequency relationship;Force-interval relationship;Calcium;Cd~(2+);Ryanodine

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Citing This Article：

Wang Shiqiang, Feng Qiang, Zhou Zengquan. Experimental analysis of the calcium source for cardiac excitation-contraction coupling in hibernator Citellus dauricus. Acta Physiol Sin 1995; 47 (6): (in Chinese with English abstract).