Effect of diphenylhydantoin on single cells in the spinal trigeminal nucleus

Abstract

With intravenous administration it was found that the response latency to electrical stimulation of the maxillary nerve is markedly increased, reaching a peak 1-5 minutes after the injection, and then gradually waning over the next 40 minutes. At the same time the postsynaptic focal potential is decreased in amplitude, while the latency and the amplitude of the presynaptic spike are only minimally affected. This is interpreted to mean that diphenylhydantoin has an inhibiting effect on synaptic transmission which is probably more significant than its effect on peripheral nerve conduction and excitability. This is discussed relative to the theory that idiopathic trigeminal neuralgia is a disease of brain stem structures rather than of the peripheral nerve.