THE ANTICONVULSANT ACTIVITY OF D-CYCLOSERINE IS SPECIFIC FOR TONIC CONVULSIONS

D-Cycloserine has been shown to exert anticonvulsant activity in maxim al electroshock seizures. The purpose of the present study was to eval uate the spectrum of D-cycloserine anticonvulsant activity using other experimental models of epilepsy. D-Cycloserine induced a dose-related decrease in the incidence of tonic convulsions induced by 120 mg/kg o f pentylenetetrazol. The ED50 of D-cycloserine for the inhibition of t he tonic convulsions was 109 mg/kg. The anticonvulsant activity was sp ecific for the D-isomer as L-cycloserine (400 mg/kg) had no effect on the tonic convulsions. D-Cycloserine had no effect on the pentylenetet razol-induced clonic convulsions induced by either 70 or 120 mg/kg pen tylenetetrazol, electrically induced nonkindled hippocampal seizures o r kindled amygdala seizures. D-Cycloserine had no effect on strychnine -induced tonic convulsions. These results indicate that D-cycloserine is inactive against clonic convulsions and may be active only against tonic convulsions mediated by brainstem sites.