Uphouse L, Caldarola-Pastuszka M, Maswood S, Andrade M, Moore N
Department of Biology, Texas Woman's University, Denton 76204.
Brain Res. 1994 Feb 21;637(1-2):173-80. doi: 10.1016/0006-8993(94)91230-0.
Ovariectomized rats were treated for 2 consecutive weeks with 25 micrograms estradiol benzoate followed 48 h later with 500 micrograms progesterone. Bilateral infusions of 200 ng 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) into the ventromedial nucleus of the hypothalamus (VMN) inhibited female sexual behavior on the first but not the second week of hormone priming. Such attenuation on the second week of priming did not appear to result from an enhanced receptivity of the female rats since there were no differences in the L/M ratios prior to drug infusion; nor was the attenuation a consequence of infusion-induced VMN damage since neither saline nor 8-OH-DPAT preinfusions prevented the later inhibitory effects of 8-OH-DPAT on lordosis behavior. However, preinfusion with 8-OH-DPAT may have reduced the duration of the inhibition. Hormone priming (without any VMN infusion) also partially attenuated the effect of 8-OH-DPAT. Both hormone priming and treatment with 8-OH-DPAT were required to eliminate the effects of the second 8-OH-DPAT treatment. Thus, the present results suggest that gonadal hormones, alone, slightly attenuate the effects of agonist activation of 5-HT1A receptors involved in the inhibition of lordosis behavior; that agonist activation of 5-HT1A receptors also produces a slight attenuation; but that both treatments together have a robust protective action against the inhibitory effect of a 5-HT1A agonist on female lordosis behavior.
对去卵巢大鼠连续两周给予25微克苯甲酸雌二醇治疗，48小时后再给予500微克孕酮。在下丘脑腹内侧核（VMN）双侧注入200纳克8-羟基-2-（二正丙基氨基）四氢萘（8-OH-DPAT），在激素预处理的第一周抑制了雌性性行为，但在第二周没有抑制作用。预处理第二周的这种减弱似乎不是由于雌性大鼠的接受性增强，因为在药物注入前L/M比值没有差异；这种减弱也不是注入诱导的VMN损伤的结果，因为生理盐水和8-OH-DPAT预注入都不能阻止8-OH-DPAT随后对脊柱前凸行为的抑制作用。然而，8-OH-DPAT预注入可能缩短了抑制的持续时间。激素预处理（不进行任何VMN注入）也部分减弱了8-OH-DPAT的作用。激素预处理和8-OH-DPAT治疗都需要消除第二次8-OH-DPAT治疗的效果。因此，目前的结果表明，单独的性腺激素会略微减弱参与抑制脊柱前凸行为的5-HT1A受体激动剂激活的作用；5-HT1A受体激动剂激活也会产生轻微的减弱作用；但这两种治疗一起对5-HT1A激动剂对雌性脊柱前凸行为的抑制作用有强大的保护作用。
