Ion channels activated by acetylcholine and gamma-aminobutyric acid in freshly dissociated sympathetic neurones of the rat.

Transmitter-activated channels in freshly isolated neurones from sympathetic ganglia of young rats have been examined using the patch-clamp technique. Acetylcholine (ACh), gamma-aminobutyric acid (GABA) and (in about one third of cells) glycine produced an inward current and an increase in current noise when perfused onto voltage-clamped neurones. The ACh noise was fitted with a single Lorentzian spectrum with a time constant of 13.1 ms at -70 mV. Outside-out membrane patches allowed high-resolution measurements of single ACh- and GABA-activated channels. The ACh-channels had a conductance of 30 pS.