Abstract

Diphenylthiohydantoin exhibits a spectrum of pharmacologic activity similar to that of diphenylhydantoin in the cat spinal cord. In addition to evidence of neurodepression, however, the former compound enhances polysynaptic discharges and depresses presynaptic inhibition in doses that do not influence monosynaptic reflex spike amplitude. Diphenylthiohydantoin enhances dorsal root potentials when evoked by dorsal root stimulation, but not when evoked by stimulation of the nerve to the posterior biceps-semitendinosus. The effects of diphenylthiohydantoin on the cat spinal cord, unlike those of diphenylhydantoin, are rapid in onset and short in duration.