A simple in vitro method to study the trigeminal ganglion.

This report describes a simple in vitro method to harvest and study the electrophysiological properties of the trigeminal ganglion of the rat. In suction electrode recordings from the proximal nerve end, two distinct peaks are identified in the compound action potential evoked by electrical stimulation of the distal nerve. gamma-Aminobutyric acid (GABA), added to the perfusion fluid, caused a positive shift in the DC potential (depolarization) and a partially selective decrease in the amplitude of the slow-conduction peak. Reversible antagonism of the GABA effect by picrotoxin and bicuculline suggests that both responses are receptor mediated. There was no response to carbamazepine or L-baclofen, suggesting that ganglionic polarization does not play a major role in the action of these drugs in trigeminal neuralgia.