Cerebrospinal fluid GABA reductions in seizure patients evoked by cerebellar surface stimulation

Abstract

Lumbar CSF GABA levels determined by fluorometric assay in 4 seizure patients were significantly lower during bilateral, continuous cerebellar stimulation than those determined after a 7 day period without stimulation. The CSF GABA concentrations during chronic unilateral, alternating cerebellar stimulation were reduced in 3 seizure patients but unchanged in a 4th patient. The percentage decrease in CSF GABA appeared to be independent of cerebellar stimulation frequency. GABA-mediated neuronal transmission is apparently depressed during cerebellar surface stimulation, and this evoked reduction in GABA activity may compromise the efficacy of cerebellar stimulation in the treatment of epilepsy. Lumbar CSF cyclic GMP levels determined by radioimmunoassay were not significantly altered by either mode or frequency of cerebellar stimulation.