Comparison of desensitization and time-dependent block of the acetylcholine receptor responses by chlorpromazine, cytochalasin B, triton X-100 and other agents.
1 Chlorpromazine, cytochalasin B, Triton X-100, lidocaine, QX-314, pentobarbitone, heptanol and ethanol, but not benzocaine or methylguanidine, caused a time-dependent inhibition of acetylcholine (ACh) potentials. Increasing the concentration of the agents increased the rate of inhibition. 2 The recovery rate from the time-dependent inhibition was the same as from desensitization except in Triton X-100 which slowed the recovery. 3 Hyperpolarizing the membrane potential caused an increase in the rate of the time-dependent inhibition. 4 It is suggested that the time-dependent inhibition and desensitization are very similar phenomena, with either ACh (in desensitization) or an agent (in time-dependent inhibition) causing a block of the activated ACh receptor, and with dissociation from the binding site being very slow. 5 Many of the agents also cause a steady state inhibition of the ACh receptor which appears to be caused by a separate blocking action of the agents.
D000109:Acetylcholine / Q000378:metabolism; D000818:Animals; D001001:Anura; D002746:Chlorpromazine / Q000494:pharmacology*; D003571:Cytochalasin B / Q000494:pharmacology*; D004347:Drug Interactions; D006207:Half-Life; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects; D011092:Polyethylene Glycols / Q000494:pharmacology*; D011950:Receptors, Cholinergic / Q000187:drug effects*; D013997:Time Factors
D011950:Receptors, Cholinergic; D003571:Cytochalasin B; D011092:Polyethylene Glycols; D000109:Acetylcholine; D002746:Chlorpromazine