Three components of active membrane current in the C-neurons of rabbit cervical nodose ganglion under voltage clamp.

In the C-neurons of rabbit nodose ganglion there is a persistent slow outward current at Vm levels positive to -80 mV. This current was detectable in Na+-free Ringer and disappeared in Ca2+-free medium. Therefore it may be the Ca2+-activated K+ current. This K+ current shows a unique time and voltage dependency, suggesting that it may have a regulatory role on the excitability of C-neurons. Two other types of current also observed in C-neurons were IQ- and IA-like currents. In A-neurons, however, a Ca2+-activated K+ current was not observed at all.