van Furth W R, van Ree J M
Department of Pharmacology, Rudolf Magnus Institute for Neuroscience, Utrecht University, The Netherlands.
Brain Res. 1996 Aug 5;729(1):20-8. doi: 10.1016/s0006-8993(96)00225-9.
The sexual motivation and performance of male rats were observed in a bilevel testing chamber after bilateral infusion of 40 pmol beta-endorphin, 2.75 nmol naloxone or saline into the ventral tegmental area for four succeeding, weekly tests. In the 5 min prior to introduction of the female rat, the male rat explores the bilevel testing chamber. It was previously shown that the increase over tests of these anticipatory level changes is sexually motivated and a response to olfactory stimuli. Naloxone infusion into the VTA prevented the increase of anticipatory level changes. beta-Endorphin failed to affect the anticipatory level-changing behavior. The sexual performance was unaffected by naloxone or beta-endorphin treatment, but the number of ejaculating rats decreased with repeated testing after naloxone treatment. It is concluded that endogenous opioid systems in the ventral tegmental area contribute to the stimulation of sexual motivation and/or reward, presumably by stimulating the mesolimbic dopamine system in response to sex-related olfactory stimuli.
在连续四周每周进行一次的测试中，向雄性大鼠腹侧被盖区双侧注入40皮摩尔β-内啡肽、2.75纳摩尔纳洛酮或生理盐水后，在双层测试箱中观察其性动机和性行为表现。在引入雌性大鼠前的5分钟内，雄性大鼠会探索双层测试箱。先前的研究表明，这些预期水平变化在测试中的增加是由性动机驱动的，并且是对嗅觉刺激的一种反应。向腹侧被盖区注入纳洛酮可阻止预期水平变化的增加。β-内啡肽未能影响预期水平变化行为。性行为表现不受纳洛酮或β-内啡肽治疗的影响，但在纳洛酮治疗后，随着测试的重复，射精大鼠的数量减少。研究得出结论，腹侧被盖区内的内源性阿片系统可能通过响应与性相关的嗅觉刺激刺激中脑边缘多巴胺系统，从而促进性动机和/或奖赏的激发。
