Lordosis behavior and GABAergic neurotransmission.

gamma-Aminobutyric acid (GABA) (1.0 microgram/cannula) or muscimol (50 ng/cannula) was injected into the ventromedial hypothalamus or the lateral septi nuclei of ovariectomized rats brought to sexual receptivity by combined treatment of estrogen and progesterone. No inhibitory effects of GABA or muscimol were observed on the lordosis behavior. Furthermore, systemic (1.0 mg/kg) or intrahypothalamic (50 ng/cannula) picrotoxin administration was followed by a statistically significant increase in lordosis behavior in ovariectomized, estrogen-primed rats. No such effect was observed in ovariectomized-adrenalectomized animals, indicating its dependence on adrenal secretions. Present results do not support the hypothesis of a GABAergic mechanism in the hormonal control of lordosis behavior.