Postdecapitation convulsions in the rat measured with an Animex motility meter: relation to central alpha-adrenoceptors.

Postdecapitation convulsions (PDC) were quantified by recording the number of movements of the trunk of decapitated rats with an Animex motility meter. PDC were inhibited by alpha 1-adrenoceptor blocking agents, phenoxybenzamine and prazosin, but unaffected by alpha 2-adrenoceptor antagonists, yohimbine and piperoxan, or a beta-adrenoceptor blocker, propranolol. Chronic administration of antidepressant drugs: amitriptyline, imipramine and zimelidine augmented the PDC. Preliminary experiments with [3H]prazosin binding suggest that the increased PDC response is related to an increase in alpha 1-adrenoceptor binding, most likely owing to an increase in receptor density.