Center for Studies in Behavioral Neurobiology, Department of Psychology, Concordia University, Montréal, QC, Canada, H4B 1R6.
Pharmacol Biochem Behav. 2012 Oct;102(4):532-9. doi: 10.1016/j.pbb.2012.06.020. Epub 2012 Jun 29.
Dopamine (DA) in the medial preoptic area (mPOA) is important for the control of appetitive aspects of sexual behavior in the female rat. Recently, following infusions of DA agonists to the mPOA of females primed with estradiol benzoate (EB) alone, we found that the ratio of D1R/D2R activity within the mPOA determines the expression of appetitive behaviors (Graham and Pfaus, 2010). To further the knowledge of this mechanism, the present experiments examined the effects of intra-mPOA infusions of selective DA receptor antagonists. Ovariectomized, sexually-experienced rats primed with EB and progesterone (P) were implanted bilaterally with cannulae aimed at the mPOA and infused with 4 doses (0, 0.25, 1.0 and 4.0 μg) of the nonselective D1R/D2R antagonist flupenthixol (FLU), and selective D1R or D2R antagonists, SCH 23390 (SCH) or raclopride (RAC), respectively, in a randomized order prior to tests of sexual behavior in bilevel chambers. The high dose of FLU significantly decreased solicitations, hops and darts, and pacing behavior. The high dose of SCH also significantly decreased solicitations. In contrast, the high dose of RAC produced an increase in pacing, and a trend toward an increase in solicitations but no other effect on sexual behavior. These results reinforce the idea that the ratio of D1R/D2R activity within the mPOA of female rats is critical for the expression of appetitive behaviors, and further that this ratio is altered by P which shifts the DA effect to a predominantly facilitative D1R activation.
中脑腹侧被盖区（mPOA）中的多巴胺（DA）对于控制雌性大鼠性行为的欲望方面很重要。最近，在对仅用苯甲酸雌二醇（EB）预激的雌性动物的 mPOA 中输注 DA 激动剂后，我们发现 mPOA 内的 D1R/D2R 活性比率决定了欲望行为的表达（Graham 和 Pfaus，2010）。为了进一步了解这种机制，本实验研究了 mPOA 内选择性 DA 受体拮抗剂的输注效果。用 EB 和孕酮（P）预激的去卵巢、有性经验的大鼠双侧植入指向 mPOA 的套管，并以随机顺序输注 4 种剂量（0、0.25、1.0 和 4.0μg）的非选择性 D1R/D2R 拮抗剂氟哌啶醇（FLU）以及选择性 D1R 或 D2R 拮抗剂 SCH 23390（SCH）或雷氯必利（RAC），然后在双水平室中测试性行为。高剂量的 FLU 显著减少了求爱、跳跃和冲刺以及踱步行为。高剂量的 SCH 也显著减少了求爱。相比之下，高剂量的 RAC 增加了踱步，并表现出增加求爱的趋势，但对性行为没有其他影响。这些结果进一步强化了这样的观点，即雌性大鼠 mPOA 内 D1R/D2R 活性的比率对于欲望行为的表达至关重要，并且进一步表明这种比率受到 P 的改变，从而将 DA 效应转移到主要促进 D1R 激活。
