DOSE-DEPENDENT EFFECTS OF ESTRADIOL BENZOATE ON 5-HT1A RECEPTOR AGONIST ACTION

The lordosis-inhibiting effects of the 5-HT1A receptor agonist, (+/-)8 -hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT), were examined in o variectomized rats, hormone primed with 2.5, 7.5, or 25 mu g estradiol benzoate plus 500 mu g progesterone. 8-OH-DPAT (50, 100 or 200 ng per bilateral site) infused into the ventromedial nucleus of the hypothal amus (VMN), inhibited lordosis behavior in all hormone-treated conditi ons. However, animals primed with 2.5 mu g estradiol benzoate were sig nificantly more affected by the infusion than rats primed with 7.5 or 25 mu g of the hormone. These findings strengthen prior speculations t hat 5-HT1A receptor function is modulated by estrogen. (C) 1998 Elsevi er Science B.V. All rights reserved.