Peripheral DA receptor blockade facilitates behavioural recovery from nigrostriatal damage.

Animals were injected via the intraperitoneal route with the peripheral dopamine receptor blocker domperidone for three days before receiving bilateral lesions of the lateral hypothalamus. Pretreatment with domperidone significantly facilitated recovery from lesion imposed deficits in consummatory behaviour and motor reflex control. The enhanced behavioural recovery achieved with domperidone pretreatment was similar to that which occurs with other dopamine receptor blockers but such recovery has been attributed to the central effects of these compounds. The results from this study demonstrate that recovery from catecholamine depleting lesions, attributed previously to the development of striatal receptor hypersensitivity, may also be due to changes in dopamine receptors outside the blood-brain barrier.

Neuroleptic-like anorexia produced by an extra-cerebral DA antagonist.

The effects of the DA receptor antagonists metoclopramide and pimozide on food and water intake in male Sprague Dawley rats were compared to those of domperidone, which does not cross the blood-brain barrier, in an attempt to determine whether any extracerebral DA receptors participate in neuroleptic induced anorexia. While metoclopramide caused only minor changes in food and water intake at the doses employed both pimozide and domperidone caused a significant reduction in food intake and water consumption 1 hr and 4 hr after injection during a 4 hr intake test. These results support the hypothesis that the nigrostriatal system may not be the system principally involved in the neuroleptic induced anorexia which occurs after the administration of these drugs.