Secondary Epileptogenesis in Frog Forebrain: Effect of Inhibition of Protein Synthesis

Abstract

SUMMARY:Secondary epileptogenesis was induced in the hippocampal cortex of the paralyzed bullfrog by means of localized, unilateral, intermittent electrical stimulation (kindling). Stimuli were designed to yield a brief but definite after-discharge. In control animals a progressive increase in after-discharge duration occurred at the 1° (stimulated) site and then at the 2° site (contralateral hippocampus). Spontaneous epileptiform potentials (SEP's) occurred between stimuli, eventually independently on both sides.Cycloheximide (50 mg/kg) caused 88-99% reduction in protein synthesis, measured by 14C-leucine incorporation into brain protein. Cycloheximide-treated animals revealed no evidence of progressive prolongation of after-discharge duration when subjected to the kindling procedure (p = 0.1205xl0-7). SEP's were reduced in the cycloheximide-treated animals, and confined to 1° hemisphere (p=0.6xl0-10).Since cycloheximide did not disturb normal electrogenesis or disrupt the after-discharges, this experiment distinguishes processes dependent upon electrical events from those requiring macromolecular synthesis. Protein synthesis seems critical to the emergence of spontaneous and autonomous epileptiform behavior of neural aggregates.