Effect of L-Dopa on the Locomotor Activity of Rats pretreated with 6-Hydroxydopamine

LARGE doses of 3,4-dihydroxyphenylalanine (dopa) cause increased locomotor activity in rats and mice pretreated with a peripherally acting decarboxylase inhibitor^1–3. The effect of dopa is enhanced in animals pretreated with a mono-amine oxidase inhibitor^4–7 and reduced when the decarboxylation of dopa in the brain is inhibited¹. Consequently, the increase in motor activity is thought to be due to the formation of catecholamines in the brain.