Effects of the bicyclic GABA agonist, THIP, on myoclonic and seizure responses in mice and baboons with reflex epilepsy.

THIP, 4,5,6,7-tetra hydroisoxazolo[5,4-C]pyridine-3-ol, has been evaluated as an anticonvulsant in DBA/2 mice showing audiogenic seizures, and in baboons, Papio papio, with photosensitive epilepsy. No protection against seizures was seen after THIP, 1-4 mg/kg, intraperitoneally in mice. THIP, 8 mg/kg, reduced clonic and subsequent seizure responses at 1 h. It also reduced rectal temperature and impaired posture and spontaneous activity. In baboons THIP, 0.25-8 mg/kg, iv, failed to protect against photically induced myoclonic responses. Toxic signs after THIP, 8 mg/kg, included focal or generalised myoclonus. THIP is thus not effective against reflex epilepsy.