[The influence of several surface-active substances on neuromuscular transmission of excitation]

Microelectrode method was applied to the study of the influence of sodium bile salts (BS), saponin and between-80 on the end-plate potentials (EPP) of m. sartorius of Rana ridibunda. Bile salts in a concentration of 10(-5) g/ml did not change these potentials significantly. With increase of the BS concentration up to 10(-4) g/ml the amplitude of EPP increased 1.5- 3 times. The action of these substances in a concentration up to 10(-3) g/ml caused similar, but more rapid, increase in the EPP amplitude, and then the amplitude decreased. Saponin and tween-80 were less efffective in their action on EPP, but evoked muscle contraction. It is suggested that an increase in the EPP amplitude as a result of the action of the mentioned agents was chiefly connected with stimulation of the acetylcholine release by the nerve terminals.