Agustín-Pavón Carmen, Martínez-Ricós Joana, Martínez-García Fernando, Lanuza Enrique
Department of Cell Biology, Facultat de Ciències Biològiques, Universitat de Valéncia, Spain.
Behav Neurosci. 2008 Apr;122(2):416-25. doi: 10.1037/0735-7044.122.2.416.
Endogenous opioids mediate some reward processes involving both natural (food, sweet taste) and artificial (morphine, heroin) rewards. In contrast, sexual behavior (which is also reinforcing) is generally inhibited by opioids. To establish the role of endogenous opioids for a newly described natural reinforcer, namely male sexual pheromones for female mice, we checked the effects of systemic injections of the general opioid antagonist naloxone (1-10 mg/kg) and the agonist fentanyl (0.1- 0.5 mg/kg) in a number of behavioral tests. Naloxone affected neither the innate preference for male-soiled bedding (vs. female-soiled bedding) in 2-choice tests nor the induction of place conditioning using male pheromones as rewarding stimuli, although it effectively blocked the preference for consuming a sucrose solution. In contrast, fentanyl inhibited the preference for male chemosignals without altering sucrose preference. These results suggest that, in macrosmatic animals such as rodents, opioidergic inhibition of sexual behavior might be due, at least partially, to an impaired processing of pheromonal cues and that the hedonic value of sweet-tasting solutions and sexual pheromones are under different opioid modulation.
内源性阿片类物质介导一些涉及天然（食物、甜味）和人工（吗啡、海洛因）奖赏的奖赏过程。相比之下，性行为（同样具有强化作用）通常会被阿片类物质抑制。为了确定内源性阿片类物质在一种新描述的天然强化物（即对雌性小鼠而言的雄性性信息素）中的作用，我们在多项行为测试中检查了全身性注射一般阿片类拮抗剂纳洛酮（1 - 10毫克/千克）和激动剂芬太尼（0.1 - 0.5毫克/千克）的效果。纳洛酮既不影响二选一测试中对雄性弄脏的垫料（与雌性弄脏的垫料相比）的先天偏好，也不影响使用雄性信息素作为奖赏刺激的位置条件反射的诱导，尽管它有效地阻断了对蔗糖溶液的偏好。相比之下，芬太尼抑制了对雄性化学信号的偏好，而不改变对蔗糖的偏好。这些结果表明，在诸如啮齿动物等嗅觉灵敏的动物中，阿片类物质对性行为的抑制作用可能至少部分归因于对信息素线索的处理受损，并且甜味溶液和性信息素的享乐价值受到不同的阿片类物质调节。
