Pergolide elevation of MHPG sulphate concentration in rat hypothalamus blocked by spiperone and mimicked by other dopamine agonists.

Pergolide increased the concentration of MHPG sulphate (3-methoxy-4-hydroxy-phenylethylene glycol sulphate) in rat hypothalamus, and the increase was prevented by pretreatment with spiperone, a dopamine antagonist. An increase in hypothalamic MHPG sulphate concentration similar to that caused by pergolide was found after injection of quinpirole, a 'partial ergoline' that is a selective D2 agonist not affecting alpha-adrenoceptors, and by (-)-N-propylnorapomorphine, a dopamine agonist not related to the ergolines. Although the increase in MHPG sulphate concentration produced by pergolide had earlier been assumed to result from blockage of alpha-adrenoceptors, the present data indicate that it is an effect produced by dopamine D2 receptor stimulation.