Korzan Wayne J, Freamat Mihael, Johnson Adam G, Cherry James A, Baum Michael J
Department of Biology.
Behav Neurosci. 2013 Oct;127(5):755-62. doi: 10.1037/a0033945. Epub 2013 Aug 26.
A long-held view has been that interest of male mice in female body odors reflects an activation of reward circuits in the male brain following their detection by the vomeronasal organ (VNO) and processing via the accessory olfactory system. We found that adult, sexually naive male mice acquired a conditioned place preference (CPP) after repeatedly receiving estrous female urine on the nose and being placed in an initially nonpreferred chamber with soiled estrous bedding on the floor. CPP was not acquired in control mice that received saline on the nose before being placed in a nonpreferred chamber with clean bedding. Robust acquisition of a CPP using estrous female odors as the reward persisted in separate groups of mice in which VNO-accessory olfactory function was disrupted by bilateral lesioning of the accessory olfactory bulb (AOB) or in which main olfactory function was disrupted by zinc sulfate lesions of the main olfactory epithelium (MOE). By contrast, no CPP was acquired for estrous odors in males that received combined AOB and MOE lesions. Either the main or the accessory olfactory system suffices to mediate the rewarding effects of estrous female odors in the male mouse, even in the absence of prior mating experience. The main olfactory system is part of the circuitry that responds to chemosignals involved in motivated behavior, a role that may be particularly important for humans who lack a functional accessory olfactory system.
长期以来的观点认为，雄性小鼠对雌性体臭的兴趣反映了犁鼻器（VNO）检测到雌性体臭并通过副嗅觉系统进行处理后，雄性大脑中奖赏回路的激活。我们发现，成年、性成熟但未交配过的雄性小鼠在反复在鼻子上接受发情期雌性尿液，并被放置在最初不喜欢的房间里，房间地板上有弄脏的发情期垫料后，获得了条件性位置偏爱（CPP）。在被放置在有干净垫料的非偏好房间之前，在鼻子上接受生理盐水的对照小鼠没有获得CPP。在分别通过双侧损毁副嗅球（AOB）破坏VNO-副嗅觉功能，或通过硫酸锌损毁主嗅上皮（MOE）破坏主嗅觉功能的小鼠组中，使用发情期雌性气味作为奖赏仍能稳固地获得CPP。相比之下，接受AOB和MOE联合损毁的雄性小鼠没有获得对发情期气味的CPP。主嗅觉系统或副嗅觉系统中的任何一个都足以介导发情期雌性气味在雄性小鼠中的奖赏作用，即使在没有先前交配经验的情况下也是如此。主嗅觉系统是对参与动机行为的化学信号做出反应的神经回路的一部分，这一作用对缺乏功能性副嗅觉系统的人类可能尤为重要。
