Mesostriatal lesions and endothelial function: effects of forced movements and hypoxia on levels of circulating endothelins

We studied rats with a hemi-parkinsonian model created by lesions of mesostriatal dopaminergic neurons. Correlation between the extent of lesions and intensity of forced rotation movements (apomorphine (APO)-induced rotations, i.e., exercise) was investigated. The levels of endothelins (ET) in the circulation after rotation under normoxic and hypoxic conditions were measured. In normoxia, the rotation sessions were associated with significant decreases in circulating ET levels. Although hypoxia had no effect on the frequency of rotations induced by APO, it significantly attenuated the decrease in the ET levels in the circulation of rats with the most extensive lesions. We suggest that the mesostriatal dopaminergic system modulates endothelial function by an active process. This may have relevance for some clinical manifestations of disordered striatal function observed in humans.