STRIA TERMINALIS CONVEYS A FACILITATORY ESTROGEN EFFECT ON FEMALE RATLORDOSIS REFLEX

The effects of bilateral cut of the stria terminalis (ST) on the dosag e of estradiol benzoate (EB) needed to induce the lordosis reflex in t he ovariectomized female rat were examined. Seven different doses rang ing 0.5-20 mu g were given s.c. in oil, daily for 2 days in a counterb alanced order, at 3-week intervals. The log dose-response relationship was linear in both ST-cut and sham-operated control rats. A significa ntly larger dose of 9.3 +/- 1.4 (mean, SEM) mu g/day of EB was needed in the ST-cut rats (n = 8) to obtain a 50% lordosis quotient than in t he controls (n = 7), in which a 2.0 +/- 0.3 mu g/day dose had a simila r effect. The slope of the dose-effect curve was significantly steeper in the ST-cut rats than in the controls. The ST mediates facilitatory effects of originate presumably in the amygdala.