RESUMO
Effects of Hyoscyamus niger L on central nervous system have been known for many years. The effects of methanolic extract of H. niger L. on seizures induced by picrotoxin was studied in mice in this investigation. In this study 7 groups of animals pretreated with methanolic extract of the plant [12.5, 25, 50, 100, 200, 300, 400 mg/kg/i.p.], 20 minutes prior to the picrotoxin [12 mg/kg/ i.p.] - induced seizures. Control mice received phenobarbital [40mg/kg/ i.p.] as positive control, or saline [10 ml/kg] as negative control. The latency of seizure [sec], duration of seizure [sec] and mortality rate were determined in test and control groups. The results of this study showed that latency of seizure was increased in groups that were pretreated with doses of 100, 200, 300 and 400 mg/kg of extract. In addition, methanolic extract of H. niger L. delayed the death time in mice as compared to control that was significant with doses of 200, 300 and 400 mg/kg. The most effective dose of extract was 300 mg/kg in this investigation [P < 0.01]. In conclusion, the results showed that methanolic extract of H. niger L. posses the anticonvulsant activity against picrotoxin-induced seizures in mice. The exact mechanism[s] by which the plant exerts its anticonvulsant activity is not determined yet