Journal of Neuroscience, Vol 3, 2525-2531, Copyright © 1983 by Society for Neuroscience
Single-channel currents activated by curare in cultured embryonic rat muscle
CE Morris, BS Wong, MB Jackson and H Lecar
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.