Prevention of progesterone-induced lordosis behavior by alpha or beta adrenergic antagonists in ovariectomized estrogen-primed rats.
The effect of systemic administration of adrenergic alpha (phenoxybenzamine and prazosin) and beta (propranolol) antagonists on the lordosis behavior induced by progesterone (2.0 mg/rat) was studied in ovariectomized estradiol benzoate (4.0 micrograms/rat) primed rats. The effect of these antagonists was also tested on the lordosis behavior induced in ovariectomized rats by estradiol benzoate alone (1.25 micrograms/rat each two days). Phenoxybenzamine (0.8, 4.0 and 20.0 mg/kg), propranolol (0.8, 4.0 and 20.0 mg/kg) and prazosin (0.2 and 1.0 mg/kg) caused a dose-dependent reduction of progesterone induced lordosis. By contrast, phenoxybenzamine (4.0 mg/kg), propranolol (4.0 mg/kg) or prazosin (1.0 mg/kg) did not affect estrogen induced lordosis behavior. Results suggest the following conclusions: (1) blockage of either alpha or beta adrenoreceptors prevents progesterone induced lordosis behavior and (2) the adrenergic neuron involved in progesterone facilitation of lordosis behavior is not a part of the reflex arc for lordosis but probably modulates the activity of this system.
Fernández-Guasti
A
A
Larsson
K
K
Beyer
C
C
D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology*; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology*; D000818:Animals; D002369:Castration; D004958:Estradiol / Q000494:pharmacology; D004967:Estrogens / Q000494:pharmacology*; D005260:Female; D010643:Phenoxybenzamine / Q000494:pharmacology; D011187:Posture; D011224:Prazosin / Q000494:pharmacology; D011374:Progesterone / Q000037:antagonists & inhibitors*; D011433:Propranolol / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012726:Sexual Behavior, Animal / Q000187:drug effects*
D000317:Adrenergic alpha-Antagonists; D000319:Adrenergic beta-Antagonists; D004967:Estrogens; D010643:Phenoxybenzamine; D011374:Progesterone; D004958:Estradiol; D011433:Propranolol; D011224:Prazosin