[The effect of several surface-active substances on neuromuscular transmission in frogs].
The action of bile salts, saponin and tween-80 on miniature end-plate potentials (MEPP) and electrotonic potentials (ETP) of the muscle fibre membrane was studied in frog Rana ridibunda. Bile salts in a concentration of 10(-4) g/ml increased the frequency and amplitude of MEPP. The input resistance of the muscle fibre membrane decreased under the action of these substances. At higher concentrations (to 10(-3) g/ml) the frequency of the MEPP initially increased, then these potentials were depressed and finally they completely disappeared. Tween-80 did not change noticeably spontaneous synaptic activity, and saponin inhibited it. In Ca-free solutions bile salt were less effective. It is suggested that bile salts change the structure of the presynaptic membrane and at the same time stimulate the release of acetylcholine form the nerve terminals.
D000818:Animals; D001647:Bile Acids and Salts / Q000494:pharmacology; D002118:Calcium / Q000502:physiology; D008564:Membrane Potentials / Q000187:drug effects; D009469:Neuromuscular Junction / Q000187:drug effects*; D011136:Polysorbates / Q000494:pharmacology; D011898:Ranidae; D012503:Saponins / Q000494:pharmacology; D013501:Surface-Active Agents / Q000494:pharmacology*
D001647:Bile Acids and Salts; D011136:Polysorbates; D012503:Saponins; D013501:Surface-Active Agents; D002118:Calcium
Issledovanie deĭstviia nekotorykh poverkhnostno-aktivnykh veshchestv na nervno-myshechnuiu peredachu u liagushki