Catecholaminergic involvement in the effects of amphetamine isomers on seizure susceptibility.

The (+)-amphetamine (2.5 mg/kg) increase in pentylenetetrazol seizure was abolished by pretreatment with reserpine, alpha-methyltyrosine methyl ester (alpha-MT), FLA-63 or 6-hydroxydopa. All treatments except reserpine antagonized the increase in seizure threshold produced by (-)-amphetamine (4 mg/kg). Only reserpine +alpha-MT antagonized the decrease in seizure threshold produced by (+)-amphetamine (15 mg/kg). These results indicate that amphetamine alterations in PTZ seizure susceptibility are mediated indirectly via the release of newly synthetized and/or granular stores of catecholamines.