ピクロトキシンの作用を通しての興奮収縮連関機構の解明

金沢大学医学部研究課題/領域番号:X46095-----34605, 研究期間(年度): 1971出典：研究課題「ピクロトキシンの作用を通しての興奮収縮連関機構の解明」課題番号 X46095-----34605（KAKEN：科学研究費助成事業データベース（国立情報学研究所）） （https://kaken.nii.ac.jp/ja/grant/KAKENHI-PROJECT-X46095-----34605/）を加工して作

筋収縮強さ時間曲線に対するピクロトキシンの作用

Effects of 5mM picrotoxin on the strength-duration curve of the mechanical threshold were examined in frog skeletal muscle fibers in Ringer solution with tetrodotoxin using a point-voltage clamp method. Picrotoxin increased about ten times the efficiency of the electrical quantity i.e., the voltage and duration product above rheobasic mechanical threshold, needed for the short depolarizing pulses, corresponding to the duration of action potentials, to reach mechanical threshold

ピクロトキシンによる蛙骨格筋線維の内向整流の抑制

Using a three-electrode voltage clamp method, the effects of 5mM picrotoxin on the inward rectifier of frog skeletal muscle fibers in a high-K, Cl-free solution were examined. The instantaneous inward rectifier in the T membrane was virtually completely abolished with picrotoxin for the membrane potentials between about +80mV and －90mV, which covers full voltage range related to excitation-contraction coupling. The picrotoxin-resistant and almost time-invariant sarcolemmal inward rectifier resided for the membrane potentials more negative than about －90mV