Effects of apomorphine combined with chlorpromazine and pimozide on the estrous cycle in rats.
Chlorpromazine (CPZ) a neuroleptic which has both antiadrenergic and antidopaminergic activity when administered in doses of 5 to 25 mg/kg s.c. inhibited ovulation and induced pseudopregnancy. Pimozide which possesses only an antidopaminergic action induced only pseudopregnancy (in doses between 0.05-10 mg/kg s.c.). Apomorphine (APO), a dopaminergic agonist, prevented the pseudopregnant effect of both neuroleptics, especially of CPZ, but failed to counteract the ovulation-blocking action of CPZ. APO itself had an antiovulatory action, but only in large doses (above 5 mg/kg s.c.), and only in a few animals. Our data plead for the importance of dopaminergic mechanisms in the inhibition of prolactin secretion (by means of PIF) and for the stimulatory role of adrenergic transmission in the ovulation process (by means of LRF). These results fail to support the proposed stimulatory role of dopamine on the LRF secretion. On the contrary, they do not exclude the possibility of its inhibitory action.
D000818:Animals; D001058:Apomorphine / Q000494:pharmacology*; D002746:Chlorpromazine / Q000494:pharmacology*; D004031:Diestrus / Q000187:drug effects; D004971:Estrus / Q000187:drug effects*; D005260:Female; D008686:Metestrus / Q000187:drug effects; D010868:Pimozide / Q000494:pharmacology*; D011247:Pregnancy; D051381:Rats
D010868:Pimozide; D001058:Apomorphine; D002746:Chlorpromazine