Potentiative action of alpha- and beta-adrenergic receptor stimulation in inducing lordosis behavior.
Ovariectomized (OVX) and ovariectomized-adrenalectomized (OVX-ADX) rats were injected with estradiol benzoate (EB, 4.0 micrograms/rat) and received 44 hr by infusion into the ventromedial hypothalamic area one of the following treatments: norepinephrine (NE), clonidine (an alpha-agonist), isoproterenol (a beta-agonist) or a combination of clonidine and isoproterenol. Infusion of NE (200 ng/rat) induced lordosis in both OVX and OVX-ADX rats 15 minutes after its administration. NE-induced lordosis was blocked by systemic treatment with either the alpha-antagonist, prazosin (1.0 mg/kg), or the beta-antagonist, propranolol (4.0 mg/kg). Intrahypothalamic infusion of clonidine (200 ng/rat) or isoproterenol (200 ng/rat) induced lordosis behavior in OVX, but not in OVX-ADX rats, suggesting the involvement of adrenal secretions in this response. Combined administration of clonidine (100 ng/rat) and isoproterenol (100 ng/rat) induced lordosis behavior 15 minutes after its intrahypothalamic infusion in OVX-ADX animals. Results are discussed in relation to a model proposed for the induction of lordosis behavior involving steroid-NE interactions.
Fernández-Guasti
A
A
Larsson
K
K
Beyer
C
C
D000315:Adrenalectomy; D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000818:Animals; D002369:Castration; D003000:Clonidine / Q000494:pharmacology; D004357:Drug Synergism; D004958:Estradiol / Q000494:pharmacology; D005260:Female; D007545:Isoproterenol / Q000494:pharmacology; D009638:Norepinephrine / Q000494:pharmacology; D011187:Posture; D011433:Propranolol / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012726:Sexual Behavior, Animal / Q000187:drug effects*
D000316:Adrenergic alpha-Agonists; D000318:Adrenergic beta-Agonists; D004958:Estradiol; D011433:Propranolol; D007545:Isoproterenol; D003000:Clonidine; D009638:Norepinephrine