Single-channel currents activated by curare in cultured embryonic rat muscle.
Single cholinergic receptor channel currents activated by curare were recorded in tissue-cultured embryonic rat muscle, directly confirming curare's action as a weak cholinergic agonist. In embryonic muscle, curare, in addition to its classical action as a competitive cholinergic antagonist, produces small sustained depolarizations which can be blocked by alpha-bungarotoxin. The single-channel events are of short duration but otherwise exhibit the major features observed with other cholinergic agonists. The single-channel events are blocked by alpha-bungarotoxin. Two values of unit conductance, 30.4 +/- 3.5 pS and 47 +/- 6 pS, were measured in cells from different cultures. Histograms of open-state duration are well fit by a distribution which is a sum of two exponentials, with time constants of 0.33 +/- 0.08 msec for the fast component and 1.84 +/- 0.43 msec for the slow component.
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D002038:Bungarotoxins / Q000494:pharmacology; D002217:Carbachol / Q000494:pharmacology; D002794:Choline / Q000031:analogs & derivatives / Q000494:pharmacology; D046508:Culture Techniques; D003472:Curare / Q000494:pharmacology*; D004347:Drug Interactions; D004622:Embryo, Mammalian; D009132:Muscles / Q000502:physiology*; D009467:Neuromuscular Depolarizing Agents / Q000494:pharmacology*; D051381:Rats; D011950:Receptors, Cholinergic / Q000187:drug effects*; D013390:Succinylcholine / Q000494:pharmacology
D002038:Bungarotoxins; D009467:Neuromuscular Depolarizing Agents; D011950:Receptors, Cholinergic; C009335:subecholine; D003472:Curare; D002217:Carbachol; D013390:Succinylcholine; D002794:Choline