INTERACTION OF SULPIRIDE WITH HUMAN PITUITARY DOPAMINERGIC RECEPTORS IS SODIUM-DEPENDENT

The effects of various drugs on [3H]-spiroperidol binding to human anterior pituitary and prolactinoma membranes are studied in the presence and in the absence of NaCl in the incubation medium. In the absence of NaCl, 1-sulpiride is significantly less potent in displacing the radioactive ligand from its dopaminergic binding sites than in the presence of NaCl. On the contrary, the interaction of neuroleptics (d-butaclamol and haloperidol) and dopamine agonists (apomorphine and bromocriptine) was unaffected by the NaCl conditions.