抄録
(1) The tension and membrane potential during the caffeine contracture of frog sartorius muscle were recorded simultaneously.
(2) The membrane potential did not alter at all, while the contracture tension developed.
(3) The threseold of electric stimulus for contraction did not change during caffeine contracture, and the contraction by electric stimulus was superposed on the contracture. The nature of caffeine contracture, therefore, would be similar as a normal contraction.
(4) In the hypertonic Ringer's solution, containing 2.5-3.0 times of NaCl, in which muscle can not contract by electric stimulus in spite of the appearance of action potential, caffeine could still, produce a contracture.
(5) Caffeine could produce a contracture in the exausted muscle.
(6) Caffeine may stimulate directly the second intermediate process (activation process) between action potential and contraction, and the hypertonicity may block the first one (spike-activation link).
