Suppression of L-dopa-induced circling in rats with nigral lesions by blockade of central dopa-decarboxylase: implications for mechanism of action of L-dopa in parkinsonism.

摘要: Dopamine (DA) elevations in rat striatum produced by combined administration of L-dopa and carbidopa were abolished when was injected with NSD-1015, an inhibitor central dopa-decarboxylase. In all rats unilateral 6-OH-DA nigral lesions, L-dopa-induced contraversive circling occurred after carbidopa, but totally (in 60%) or markedly suppressed pretreatment NSD-1015. Administration the DA metabolites DOPAC HVA systemically 3-methoxytyramine intrastriatally evoked nocircling animals lesions. nigrotomies, direction reversed became ipsiversive receptors reduced addition kainic acid lesions ipsilateral striata. Findings provide evidence that rats—and analogy, efficacy parkinsonians—requires decarboxylation exogenous interaction formed striatum.