Sánchez-Catalán María-José, Orrico Alejandro, Hipólito Lucía, Zornoza Teodoro, Polache Ana, Lanuza Enrique, Martínez-García Fernando, Granero Luis, Agustín-Pavón Carmen
Departament de Farmàcia, Tecnologia Farmacèutica i Parasitologia, Universitat de València València, Spain.
Departament de Biologia Cel⋅lular, Biologia Funcional i Antropologia Física, Universitat de València València, Spain.
Front Neuroanat. 2017 Feb 23;11:8. doi: 10.3389/fnana.2017.00008. eCollection 2017.
Sexual chemosignals detected by vomeronasal and olfactory systems mediate intersexual attraction in rodents, and act as a natural reinforcer to them. The mesolimbic pathway processes natural rewards, and the nucleus accumbens receives olfactory information via glutamatergic projections from the amygdala. Thus, the aim of this study was to investigate the involvement of the mesolimbic pathway in the attraction toward sexual chemosignals. Our data show that female rats with no previous experience with males or their chemosignals display an innate preference for male-soiled bedding. Focal administration of the opioid antagonist β-funaltrexamine into the posterior ventral tegmental area does not affect preference for male chemosignals. Nevertheless, exposure to male-soiled bedding elicits an increase in dopamine efflux in the nucleus accumbens shell and core, measured by microdialysis. Infusion of the opioid antagonist naltrexone in the accumbens core does not significantly affect dopamine efflux during exposure to male chemosignals, although it enhances dopamine levels 40 min after withdrawal of the stimuli. By contrast, infusion of the glutamate antagonist kynurenic acid in the accumbens shell inhibits the release of dopamine and reduces the time that females spend investigating male-soiled bedding. These data are in agreement with previous reports in male rats showing that exposure to opposite-sex odors elicits dopamine release in the accumbens, and with data in female mice showing that the behavioral preference for male chemosignals is not affected by opioidergic antagonists. We hypothesize that glutamatergic projections from the amygdala into the accumbens might be important to modulate the neurochemical and behavioral responses elicited by sexual chemosignals in rats.
犁鼻器和嗅觉系统检测到的性化学信号介导了啮齿动物的两性间吸引，并对它们起到天然强化物的作用。中脑边缘通路处理天然奖赏，伏隔核通过来自杏仁核的谷氨酸能投射接收嗅觉信息。因此，本研究的目的是调查中脑边缘通路在对性化学信号的吸引中的作用。我们的数据表明，此前没有接触过雄性或其化学信号的雌性大鼠对雄性弄脏的垫料表现出先天偏好。向腹侧被盖区后部局部注射阿片类拮抗剂β-芬太尼透胺并不影响对雄性化学信号的偏好。然而，通过微透析测量发现，接触雄性弄脏的垫料会引起伏隔核壳部和核心部多巴胺外流增加。在伏隔核核心部注入阿片类拮抗剂纳曲酮，在接触雄性化学信号期间对多巴胺外流没有显著影响，尽管在刺激撤除后40分钟会提高多巴胺水平。相比之下，在伏隔核壳部注入谷氨酸拮抗剂犬尿氨酸会抑制多巴胺释放，并减少雌性大鼠调查雄性弄脏的垫料所花费的时间。这些数据与之前关于雄性大鼠的报道一致，即接触异性气味会引起伏隔核中的多巴胺释放，也与雌性小鼠的数据一致，即对雄性化学信号的行为偏好不受阿片类拮抗剂影响。我们推测，从杏仁核到伏隔核的谷氨酸能投射可能对调节大鼠性化学信号引发的神经化学和行为反应很重要。
