EFFECTS OF ZINC ON MEMBRANE POTENTIAL AND TWITCH TENSION OF FROG SKELETAL MUSCLE

概要

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Effects of Zn^<2+> in Ringer's solution and in low Ca^<2+> Ringer's solution on membrane potential and twitch tension were studied in bull frog skeletal muscle by means of an intracellular glass microelectrode and an isometric tension transducer. Zn^<2+> (50μM) prolonged the duration of action potential and increased twitch amplitude, but did not alter the time between the onset of tension and the maximum rate of rise of tension (the maximum dT/dt). Exposure of the fiber to low Ca^<2+> solution caused decrement following transient enchancement of twitch tension and delay of the time to the maximum dT/dt, whereas there was no effect on action potential. The prolongation of the time to the maximum dT/dt in low Ca^<2+> solution was overcome by the addition of Zn^<2+> to the medium. These results suggest that Zn^<2+> improved the excitaion-contraction coupling impaired by Ca^<2+> withdrawal from external medium, in addition to the effect of Zn^<2+> on delayed K^+ channel.
名古屋市立大学の論文
1984-07-24