DIRECT CHEMICAL STIMULATION OF DOPAMINERGIC MECHANISMS IN NEOSTRIATUM OF RAT

Unilateral intrastriatal injection of dopamine, noradrenaline, and apomorphine, as well as unilateral intrastriatal application of dopamine and apomorphine crystals, produced in nialamide-pretreated rats an asymmetric posture and turning contralateral to the side of drug administration. These effects could be blocked by a prior bilateral intrastriatal injection of chlorpromazine. A unilateral injection of chlorpromazine alone produced turning ipsilateral to the side of injection. No consistent motor effects could be observed after unilateral injection of dopamine into the thalamus and neocortex. As assessed histochemically, the intrastriatally injected dopamine was taken up into the nerve terminals of the nucleus caudatus-putamen and also the axons of the nigro-neostriatal dopamine pathway. An identical histochemical distribution was observed for intrastriatally injected noradrenaline. The above findings were interpreted as illustrating the importance of dopamine for the mediation of certain types of postural and locomotor activity. © 1969.