Effect of combined treatment with dopaminergic and GABA-ergic drugs on the threshold for maximal electroconvulsions in mice.

Aminooxyacetic acid (AOAA; 20 and 40 mg/kg), baclofen (15 and 20 mg/kg), gamma-hydroxybutyric acid (GHBA; 250 mg/kg) and gamma-aminobutyric acid (GABA: 3000 mg/kg), administered intraperitoneally, increased the convulsive threshold in mice but to a relatively small degree. Bicuculline and picrotoxin were shown to reverse these anticonvulsant effects except for baclofen. Apomorphine (10 mg/kg), amantadine (100 mg/kg) and L-DOPA (62 . 5 and 125 mg/kg) potentiated the action of AOAA (20 mg/kg). Also apomorphine (5 and 10 mg/kg) and amantadine (25 and 100 mg/kg) potentiated the anticonvulsant activity of baclofen (15 mg/kg). Combined treatment with baclofen (15 mg/kg) and amantadine (100 mg/kg) resulted in about 4-fold increase in the convulsive threshold. However, the action of GABA and GHBA was poorly affected by dopaminergic agonists, amantadine even decreased the threshold in animals pretreated with these substances. The results obtained in this study suggest dopaminergic stimulation to be of importance in potentiating the anticonvulsant action of some GABA-ergic drugs.