The effects of estrogen on apomorphine-induced hypothermia and stereotypy in the rat.
The effects of various doses of estrogen on apomorphine (Apo)-induced hypothermia and stereotypy were investigated in ovariectomized rats. Daily administration of estradiol (5, 15 or 100 micrograms/kg) for 4 days or estradiol (100 micrograms/kg) for 3 days, followed by 4 and 72 hr withdrawal periods respectively, had no effect on apomorphine-induced hypothermia or stereotypy in a cold (4 degrees C) environment, although both effects were blocked by haloperidol. Large doses of estradiol (100 micrograms/kg) given for 3 days, followed by either 24 or 72 hr withdrawal, slightly attenuated apomorphine-induced stereotypy at 22 degrees C. Stereotypy observed at 22 degrees C was of greater magnitude than that seen at 4 degrees C. The results indicate that although high, non-physiological levels of estrogen may attenuate striatal-dependent stereotypies, this hormone has no detectable influence on dopaminergic mechanisms in the preoptic-anterior hypothalamic regions that are thought to mediate apomorphine-induced hypothermia.
D000818:Animals; D001058:Apomorphine / Q000494:pharmacology*; D003080:Cold Temperature; D004298:Dopamine / Q000378:metabolism; D004958:Estradiol / Q000031:analogs & derivatives* / Q000494:pharmacology; D006220:Haloperidol / Q000494:pharmacology; D006801:Humans; D007032:Hypothalamus, Anterior / Q000187:drug effects; D007035:Hypothermia / Q000139:chemically induced*; D051381:Rats; D011919:Rats, Inbred Strains; D013239:Stereotyped Behavior / Q000187:drug effects*
D004958:Estradiol; C010452:estradiol-17 beta-benzoate; D006220:Haloperidol; D001058:Apomorphine; D004298:Dopamine