Trevino A, Wolf A, Jackson A, Price T, Uphouse L
Department of Biology, Texas Woman's University, Denton, Texas 76204, USA.
Horm Behav. 1999 Jun;35(3):215-23. doi: 10.1006/hbeh.1999.1515.
The effects of bilateral VMN infusion with the 5-HT1A receptor agonist, (+/-)-8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT; 200, 1000, or 2000 ng), on lordosis behavior were examined in hormonally primed ovariectomized rats. When rats were given a single injection with 25 microg estradiol benzoate followed 48 h later with 500 microg progesterone, inhibition of lordosis behavior was evident at all doses of 8-OH-DPAT. However, when rats were treated with 25 microg estradiol benzoate followed 7 days later with a second injection of 25 microg estradiol benzoate and then progesterone, none of the doses of 8-OH-DPAT effectively inhibited lordosis behavior. In some rats, cannulae were located near the most rostral portion of the VMN. In these rats, there was no effect of the second estrogen treatment on the response to 8-OH-DPAT. Therefore, a second experiment was performed to specifically evaluate the effects of two estradiol benzoate treatments on the response to bilateral 8-OH-DPAT infusion in the rostral VMN. In contrast to the reduced effectiveness of the 8-OH-DPAT infusion in the mid to caudal VMN in rats given two injections with estradiol benzoate, 2000 ng 8-OH-DPAT continued to effectively inhibit lordosis behavior following the 5-HT1A receptor agonist's infusion into the more rostral areas. These findings are discussed in relation to earlier studies in which the potency, but not the efficacy, of 8-OH-DPAT was reduced following systemic treatment with the 5-HT1A receptor agonist.
在激素预处理的去卵巢大鼠中，研究了双侧腹内侧核（VMN）注射5-羟色胺1A（5-HT1A）受体激动剂（±）-8-羟基-2-（二正丙基氨基）四氢萘（8-OH-DPAT；200、1000或2000纳克）对脊柱前凸行为的影响。当给大鼠单次注射25微克苯甲酸雌二醇，48小时后再注射500微克孕酮时，所有剂量的8-OH-DPAT均明显抑制脊柱前凸行为。然而，当大鼠先接受25微克苯甲酸雌二醇治疗，7天后再注射一次25微克苯甲酸雌二醇，然后注射孕酮时，所有剂量的8-OH-DPAT均不能有效抑制脊柱前凸行为。在一些大鼠中，插管位于VMN最靠前的部分。在这些大鼠中，第二次雌激素治疗对8-OH-DPAT反应没有影响。因此，进行了第二项实验，专门评估两次苯甲酸雌二醇治疗对双侧8-OH-DPAT注入VMN前部反应的影响。与给两次苯甲酸雌二醇注射的大鼠中8-OH-DPAT注入VMN中后部效果降低相反，在将5-HT1A受体激动剂注入更靠前的区域后，2000纳克8-OH-DPAT仍能有效抑制脊柱前凸行为。结合早期研究对这些发现进行了讨论，早期研究表明，全身用5-HT1A受体激动剂治疗后，8-OH-DPAT的效价降低，但疗效未降低。
