Electroconvulsive shock and L-dopa reduce head-turning induced by electrical stimulation of the caudate nucleus in the rat.

The effect of repeated electroconvulsive shock (ECS) and L-dopa on contralateral head-turning induced by electrical stimulation of the caudate nucleus in rats was determined. Repeated ECS treatment consisting of a single daily ECS for 10 days was found to increase the number of caudate stimuli required to induce head-turning. As reported by others, oral L-dopa (250 mg/kg) was also found to antagonize the caudate stimulation-induced head-turning. The repeated ECS treatment had an additive effect with the 250 mg/kg L-dopa dose to increase the number of stimulations to induce the head-turn. These findings support previous reports that repeated ECS enhances dopamine-mediated behaviors as well as the theory that caudate stimulation-induced head-turning is mediated in part by dopaminergic mechanisms.