Аннотация:Abstract The functional role of the nigro‐striatal dopamine (DA) system has been investigated on the basis of a recent detailed mapping of its path and a new method of lesioning the catecholamine systems selectively by intracerebral injection of 6‐hydroxydopamine (6‐OH‐DA). The investigation was especially focused on the symptoms of adipsia, aphagia, hypokinesia and catalepsia after lateral hypothalamic lesions as such lesions may interrupt the ascending DA axons. Electrocoagulations or 6‐OH‐DA lesions were performed bilaterally at several sites along the DA pathway and the behavioural effects were evaluated in relation to the histochemically detected lesion of the DA pathway. It was concluded that bilateral complete degeneration of the nigro‐striatal DA pathway produces severe, long lasting adipsia and aphagia, hypoactivity, difficulties to initiate activity and loss of exploratory behaviour and curiosity. Experiments with DA receptor stimulating and blocking drugs supported the lesion results. Catalepsia and somnolence were attributed to the interruption of other pathways. The results suggest an important role for the nigro‐striatal DA system and the striatum in the control of behaviour. A number of symptoms earlier related to the hypothalamus may in fact be due to disturbance of the nigro‐striatal DA system.