REGIONAL ACCUMULATION OF CATECHOLAMINES FORMED FROM TYROSINE-14C IN RAT BRAIN - EFFECT OF CHLORPROMAZINE

The in vivo accumulation of dopamine-14C and noradrenaline-14C in eight regions of the rat central nervous system was determined following an i.v. infusion of tyrosine-14C. In the brains of untreated animals dopamine-14C accumulated in high amounts in the striatum and median eminence whereas low amounts were found in the cerebellum and cerebral cortex. The accumulation of noradrenaline-14C was high in the median eminence and brain stem and low in the cerebellum and cerebral cortex. Chlorpromazine markedly accelerated the accumulation of dopamine-14C in the striatum but had no effect on dopamine-14C accumulation in other brain regions. Neither in the striatum nor in other regions was the amount of noradrenaline-14C significantly altered by chlorpromazine. From the results it is suggested that chlorpromazine selectively accelerates dopamine synthesis in the nigro-neostriatal dopamine pathway. The significance of the findings in relation to the neuroleptic action of the drug is considered. © 1969.