Neural mechanisms of sexual motivation in female rats

条件位置偏好（CPP）范式被用于评价性激励动机，以及药物的强化性。马丁内斯和帕雷德斯（2001）证明了CPP仅与雌性大鼠的有节奏交配有关。另一方面，Meerts, Christensen & Clark（2005）报告称，无论交配是有节奏的还是无节奏的，雌性大鼠都表现出对与交配相关的区域的位置偏好。在这项研究中，我们解决了雌性大鼠交配诱导CPP的这个有争议的方面。此外，一些研究揭示了性行为与药物滥用之间的关系，表明性行为和药物的强化特性存在于共同的神经基础上。在本研究中，我们研究了阿片受体拮抗剂纳洛酮对雌性大鼠交配相关CPP完成的影响。选用雄性和雌性Long-Evans大鼠（8周龄）。经5 μg苯甲酸雌二醇（estradiol benzoate， EB）和500 μg黄体酮（孕酮，P）注射后，所有雌鼠均切除卵巢，给予交配e。之后，根据2x2实验设计、交配条件（有节奏或无节奏）和药物治疗（4 mg /kg纳洛酮或生理盐水），将受试者分为4组（每组n=8）。每只雌性在交配前注射EB和P。在第1、3、5次条件训练中，所有被试均被注射生理盐水，并在不交配的情况下直接从它们的家笼转移到首选隔间30分钟。在第2、4、6次条件训练中，受试者分别腹腔注射生理盐水或纳洛酮。注射后1分钟，受试者被允许在有节奏或无节奏的情况下与雄种马交配。在接受15次介绍后，立即将雌性放置在非偏好隔间中30分钟。与Meerts等人（2005）的发现一致，无论交配是有节奏的还是无节奏的，雌性都表现出对与交配相关的隔间的位置偏好。阿片拮抗剂纳洛酮可阻断仅由节奏交配引起的CPP。这些结果表明，有节奏和无节奏的交配可能涉及不同的性互动奖励机制。少

The conditioned place preference (CPP) paradigm has been used for evaluating sexual-incentive motivation, as well as reinforcing property of drugs. Martinez & Paredes (2001) demonstrated a clear CPP associated only with paced mating in female rats. On the other hand, Meerts, Christensen & Clark (2005) reported that female rats showed a place preference for the compartment associated with mating, whether mating was paced or non-paced.In this study, we addressed this controversial aspect of mating-induced CPP in female rats. In addition, several studies revealed the relationship between sexual behavior and drug abuse, suggesting that the reinforcing properties in sexual behavior and drugs lie on a common neural basis. In the present study, we examined the influence of an opioid receptor antagonist, naloxone, on accomplishment of CPP associated with mating in the female rat.Male and female Long-Evans rats (8 weeks old at start) were used. All females were ovariectomized and given mating e … More xperiences after injections of 5 μg estradiol benzoate (EB) and 500 μg progesterone (P). After that, subjects were divided into 4 groups (in each group, n=8) according to 2x2 experimental design, mating conditions (paced or non-paced) and drug treatments (4 mg /kg naloxone or saline). Each female received injections of EB and P before mating. On the 1st, 3rd, and 5th conditioning sessions, all subjects were injected saline and transferred directly from their home cage to preferred compartment for 30 min without copulation. On the 2nd, 4th and 6th conditioning sessions, subjects were injected intraperitoneally with either saline or naloxone. One min after injection, the subjects were allowed to mate with stud males in either paced or non-paced condition. Immediately after receiving 15 intromissions, the females were placed in the non-preferred compartment for 30 min. In consistent with the findings by Meerts, et. Al. (2005), females showed a place preference for the compartment associated with mating, whether mating was paced or non-paced. Opiate antagonist, naloxone, blocked the CPP induced only by paced mating.These results suggest that different reward mechanisms for sexual interaction may be involved in paced and non-paced mating. Less