Relationship between calcium-dependent potassium channel and ectopic spontaneous discharges of injured dorsal root ganglion neurons in the rat

The ectopic spontaneous discharges (ESD) of single myelinated dorsal root fiber originated from the injured dorsal root ganglion (DRG) neurons were recorded in vivo. When [Ca2+](o) perfusing the injured DRG had been enhanced or caffeine been used, the ESD was inhibited in dose-dependent manner, while using Ni2+ or EGTA, the ESD facilitated. The increment of [K+](o) and the use of TEA could both facilitate the ESD in dose-dependent manner. Apamin, a special antagonist of calcium-dependent potassium channel (K(Ca)), had markedly increased the number of ESD. These results suggest that the generation of ESD has close relation to the activity of K(Ca) channel. (C) 1999 Elsevier Science B.V. All rights reserved.