Fig. 9.

Muscarinic currents measured with voltage clamp under conditions in which voltage-sensitive conductances were blocked. The external solution contained 0.5 μm TTX, 40 μm DNQX, 1 μm strychnine, 5 mmCsCl, and 200 μm CdCl₂; the internal solution was normal. A, Muscarine (20 μm)blocked outward and inward currents and elicited a negative shift of the holding current. B, The difference current is not obviously time- or voltage-dependent. C,I–V relationship of the difference current. The current amplitudes were averaged through the whole length of each trace. The reversal potential (−85.4 mV) was calculated from a linear fit to the measurements.