Enhancement of spike and wave discharges by GABAmimetic drugs in rats with spontaneous petit-mal-like epilepsy.

Certain Wistar rats from our laboratory colony present genetically determined seizures similar to human petit-mal absences. Muscimol, THIP and L-baclofen, agonists of GABA receptors, and gamma-vinyl GABA (GVG), an inhibitor of GABA degradation, enhanced the duration of spontaneous petit-mal-like seizures in a dose-dependent fashion. These findings raise questions as to the role of GABAergic neurotransmission in the occurrence of this type of spontaneous spike and wave discharges.