Differential neurohumoral modulation of myoclonic and clonic seizures.

Differential effects of neuropharmacological drugs upon susceptibility to flurothyl-induced myoclonic and clonic convulsions were assessed in two selectively bred lines of mice. Dopaminergic drugs (apomorphine and haloperidol) only affected myoclonus, whereas cholinergic (pilocarpine and scopolamine), gabaergic (AOAA and bicuculline), and serotonergic (PCPA) compounds principally influenced clonus. Noradrenergic drugs (clonidine, phentolamine and sotalol), however, altered the expression of both types of seizures. The apparent differential neurohumoral modulation of myoclonus and clonus is discussed in light of previous suggestions that these behaviors have separate neural substrates.