The effects of reserpine, iproniazid and L-dopa on electrically-induced spinal cord seizures

The effects of selected drug treatments on spinal cord norepinephrine (NE), dopamine (DA), and 5-hydroxytryptamine (5-HT) were compared to the effects of these same treatments on electrically-induced spinal cord seizure. Depletion of monoamine stores by reserpine facilitated spinal cord seizures. In contrast, L-DOPA, given to animals pretreated with iproniazid, exerted an anticonvulsant effect and elevated spinal cord NE and DA levels. L-DPOA administered alone produced a substantial elevation in DA levels but had no effect on spinal cord seizures. Iproniazid had no effect on monoamines, whereas it facilitated seizure activity. These observations support the concept that spinal cord noradrenergic, but not 5-hydroxytryptaminergic or dopaminergic neurons act as attenuators of convulsive activity. The effect of iproniazid on spinal cord seizures, in the absence of an observed alteration in monoamine levels, provides evidence that this effect is mediated through non-monoaminergic mechanisms.