Age dependent effects of antagonists of 5HT(1C) and α₂-adrenergic receptors on audiogenic seizures and locomotor activity in DBA/2 mice.

The effects of 5HT(1C) and α₂-adrenergic receptor antagonists cyproheptadine and yohimbine respectively, were investigated on seizure latency and severity, on locomotor activity and habituation pattern of young (20-27 days) and older (30-37 days) DBA/2 mice. Yohimbine (0.5 mg/kg) decreased and cyproheptadine (2 mg/kg) increased the seizure latency in both age groups. Additionally, cyproheptadine, but not yohimbine, increased the locomotor activity, in the old but not young mice. Yohimbine deteriorated the habituation pattern in young and old mice, while cyproheptadine affected only the habituation of older animals. Taken together these results suggest that 5HT(1C) and α₂-adrenoreceptors may be involved in the reciprocal relationship which is involved in the regulation of age-related audiogenic seizure susceptibility in DBA/2 mice.