A barbital derivative as an atypical antidepressant drug in mice.

An isopropyl derivative of barbital (5,5-diethyl-2-(isopropyloxy)pyrimidine-4,6-dione, O2IB) was administered intraperitoneally 30 min before tests in mice. Former experimental investigations have shown that O2IB has an antidepressant psychopharmacological spectrum. It increases toxicity of yohimbine in mice at 175 mg/kg, antagonises from 50 mg/kg on hypothermia induced by a high dose of apomorphine and is active on the behavioural despair test at 125 mg/kg. These effects are those observed with classical antidepressants. Since phenytoin has an antidepressant profile in mice, carbamazepine is active on manic-depressive illness and beta-mimetic drugs are antidepressants, the question presents itself whether isopropylation or anticonvulsive activity is more important for the antidepressant psychopharmacological spectrum, or whether both are of equal importance.