A K⁺ channel activated by cholinergic muscarinic receptors in chick ciliary ganglion neurons at early developmental stage

Embryonic chick ciliary ganglion (CG) neurons obtained from E7-E8 ganglia maintained in serum-free medium were stimulated with 50 μM muscarine. A fast hyperpolarization of the membrane potential was observed in 25% of the cells tested, that in some cases was associated with a slower depolarization. Accordingly, in voltage clamp experiments, either an outward current or a biphasic current response could be observed. Single-channel experiments provide evidence that these signals can be associated to the activation of a K ⁺ channel whose conductance is 20 pS.