The involvement of dopaminergic systems with the stereotyped behaviour patterns induced by methylphenidate.

Abstract

Abstract The electrolytic brain lesion technique was used to investigate the role of dopamine-containing areas and pathways in the rat for the mediation of methylphenidate stereotypy. Ablation of the dopaminergic pathways to the extrapyramidal areas at the level of the lateral hypothalamus or substantia nigra was without effect suggesting a postsynaptic site of action in the extrapyramidal nuclei. This site was shown to be the paleo- and not the neostriatum. Deafferentation of the mesolimbic nuclei abolished the weaker components of stereotypy in the acute phase. This effect was generally reflected by ablation of the tuberculum olfactorium but not by nucleus accumbens septi or nucleus interstitialis stria terminalis lesions. The action in the mesolimbic areas may, therefore, involve presynaptic mechanisms. Lesion of the nucleus amygdaloideus centralis abolished the intense components of stereotypy. The greater importance of extrapyramidal function for the action of methylphenidate would indicate a possible value for this agent in the treatment of Parkinson’s disease.