Enhancement of hypophysectomy-induced dopamine receptor hypersensitivity in male rats by chronic haloperidol administration.
It has been reported that hypophysectomy (HYPOX) would antagonize the development of a neuroleptic-induced dopamine receptor hypersensitivity, and suggested that the neuroleptic-induced dopamine receptor hypersensitivity may be mediated by the neuroleptic-induced hyperprolactinemia. Conversely, we and others have reported on the ability of HYPOX animals to develop a neuroleptic-induced dopamine receptor hypersensitivity. The present study was undertaken to define the possible role(s) of prolactin in the modulation of striatal dopamine receptor sensitivity. The data from these studies indicate: that HYPOX alone will result in the development of a striatal dopamine receptor hypersensitivity; that the HYPOX-induced dopamine receptor hypersensitivity could be increased by the chronic administration and withdrawal of haloperidol; that administration of prolactin to HYPOX rats would partially antagonize the development of the neuroleptic-induced dopamine receptor hypersensitivity; and that the administration of prolactin alone had minimal effects on the apomorphine-induced behavior or neurochemistry of the HYPOX animals. These results suggest that the neuroleptics do not require the presence of a pituitary secretion (specifically, prolactin) to induce a striatal dopamine receptor hypersensitivity; however, they do indicate that a pituitary secretion, perhaps prolactin, may have the ability to modulate striatal dopamine sensitivity.
D000818:Animals; D001058:Apomorphine / Q000494:pharmacology; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D005260:Female; D006220:Haloperidol / Q000494:pharmacology*; D006801:Humans; D007016:Hypophysectomy; D007700:Kinetics; D008297:Male; D011388:Prolactin / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D011954:Receptors, Dopamine / Q000187:drug effects / Q000378:metabolism*; D013134:Spiperone / Q000378:metabolism; D013239:Stereotyped Behavior / Q000187:drug effects
D011954:Receptors, Dopamine; D013134:Spiperone; D011388:Prolactin; D006220:Haloperidol; D001058:Apomorphine