Effects of acute and chronic paleocerebellar stimulation on experimental models of epilepsy in the cat: studies with enflurane, pentylenetetrazol, penicillin, and chloralose.

Abstract

Effects of acute and chronic paleocerebellar stimulation were evaluated in four experimental models of epilepsy in 24 adult cats chronically implanted with bilaterally symmetric parasagittal electrocorticographic electrodes and anterior lobe cerebellar stimulation electrodes. Pentylenetetrazol was given intraveneously in 50-mg increments or 4% enflurane was inspired until grand mal seizures occurred spontaneously or were triggered by photic or auditory stimuli. Alpha-chloralose, 50 mg/kg, was injected intraperitoneally to produce a model of stimulus-sensitive myoclonus and sodium penicillin G, 350,000 units/kg, was injected intramuscularly to produce a model of petit mal epilepsy. One- to 250-Hz electrical stimulation of paleocerebellar cortical surfaces was performed with constant-voltage or constant-current stimulators at threshold and suprathreshold intensities with average intensities of 8 V and 2.5 mA, respectively. Acute or chronic, threshold or suprathreshold paleocerebellar stimulation did not predictably alter the electrographic or clinical manifestations in any of these four models.