Resting Potential of the Muscle-Cell in Toad's Stomach.

1. The membrane potential was studied with microelectrode techniques on muscle cells of an isolated strip of toad's stomach. The solutions in which the muscle cells of an isolated strip of toad's stomach. The solutions in which the muscle strip was immersed were Ringer's or sucrose solution, and the effects of a few autonomic stimulating agents were observed. 2. The potential values were statistically different between the pyloric portion and gastric body in both Ringer's and sucrose solution. In the former, they were 50.5±0.7 (standard error) mV at pyloric portion and 45.0±0.9mV at gastric body. If the tip potentials were corrected, these membrane potential would be 58.3±1.7 mV at pyloric portion and 52.9±1.5 mV at gastric body, respectively. It was likely that the junction potential at an indifferent electrode is negligible. 3. In isotonic sucrose solution, the measured potential was higher (membrane was hyperpolarized) than in Ringer's, and the factors concerning this phenomenon were discussed. 4. The effect of acetylcholine or barium chloride was responsible for the depolarization of muscle membrane. The effect of adrenaline on the muscle membrane was minor. 5. Although the muscle strip showed rhythmical contraction by adding acetylcholine (10-5) or barium chloride (4.4 mM～ 7.4mM) to the bathing Ringer's solution, the evident action potentials could not be recorded.