1985 年 78 巻 1 号 p. 103-108
The posterior semicircular canal of the frog was isolated in frog Ringer's solution. The ampullary wall was cut, and the entire cupula was exposed. The surface of the utricular side and the lateral surface of the cupula were depressed 20μm by a fine glass pipette. The action potential from the posterior ampullary nerve was recorded with a glass suction electrode. Nine points on the utricular surface and 2 points on the lateral surface of the cupula were selected for stimulation. The maximum action potential was recorded upon stimulation of the lowest point on the utricular surface. The potential decreased as the stimulated point approached the top of the cupula. There was no difference in response to stimuli between the central one-third and the lateral one-third of the cupula. When the lateral side of the cupula was depressed, the action potential was markedly reduced. In contrast to stimulation of the utricular surface, stimulation of the upper lateral surface yielded a greater action potential than did stimulation of the lower.