Single acetylcholine channel currents in sympathetic neurons

Single acetylcholine (ACh) channel currents were studied by the gigaohm patch-clamp technique in cultured sympathetic neurons of the bullfrog, Rana catesbeiana. Recordings were made at 22C oncell-attached and excised membrane patches. When ACh (0.5-1 μM) was present in the pipette, a single class of inward currents was observed with a chrod conductance of 30 pS and reversal potential of -2 mV. The mean channel open time was 11.6 ms at -65 mV and showed little or no voltage-dependence over the range -85 to -45 mV. These channels appear to mediate the fast nicotinic excitatory postsynaptic current.