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Effects of inosine on the transmembrane potential and contractility of hypoxic cardiac muscle

Chu Pingchun, Li Zhenyuan, Yu Tehchang

Department of physiology, Zhejing Medical University

Abstract

Effects of inosine on transmembrane potential and contractility were observed
in guinea pig papillary muscle. The results indicated that in normal, ventricular muscle, inosine prolonged the action potential duration [APD_(10), APD_(50)]，especially at the early phase of repolarization. In the hypoxic muscle, it caused anincrease in resting potential, action potential amplitude, maximum upstroke velocity of 0 phase depolarization and prolongation of APD. Inosine increased the contractility of normal myocardium and retarded the decline of contractility following hypoxia, which showed in a dose-dependent manner. The effects of inosine on the transmembrane potential of hypoxic cardiac muscle suggested that it might have an anti-arrhythmic action, especially in the hypoxic heart. The influence of inosine on the contractility of isolated papillary muscle indicated that it had a direct, positive inotropic action on the myocardium.

Key words: Inosine;Hypoxic cardiac muscle;Transmembrane potential;Cardiac contractile force

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Citing This Article：

Chu Pingchun, Li Zhenyuan, Yu Tehchang. Effects of inosine on the transmembrane potential and contractility of hypoxic cardiac muscle. Acta Physiol Sin 1987; 39 (4): (in Chinese with English abstract).