Measurement of anticonvulsant activity in the Papio papio model of epilepsy.

The status of Papio papio as a model of clinical epilepsy has been reviewed. The anticonvulsant effects of single doses of various classic and experimental agents have been compared against seizures induced in the P. papio by intermittent light stimulation. Long-acting but not short-acting barbiturates have been shown fully to control seizures with minor sedative effects. Diphenylhydantoin (in chronic doses only) and trimethadione are often effective but not consistently so. Diazepam and clonazepam block seizures at very low doses both acutely and chronically. However, an initial dose well above threshold seems essential if anticonvulsant effects are to be maintained under chronic administration of these compounds. Carbamazepine and SC 13504 (1-benzhydryl-4(6 methyl-2-pyridylmethyleneimino)piperazine), as well as two nonstimulant analogues of amphetamine, were shown to be promising anticonvulsants in this model. A biphasic action of tetrahydrocannabinol, anticonvulsant at a few micrograms per kilogram but not at higher doses, was also demonstrated. Finally, the anticonvulsant action of intraventricular epinephrine and norepinephrine was reported.