Larsen Caroline M, Kokay Ilona C, Grattan David R
Centre for Neuroendocrinology and Department of Anatomy and Structural Biology, Box 913, University of Otago, Dunedin 9001, New Zealand.
Horm Behav. 2008 Apr;53(4):509-17. doi: 10.1016/j.yhbeh.2007.11.020. Epub 2007 Dec 15.
Prolactin is required for rapid onset of maternal behavior after parturition, inducing adaptive changes in the maternal brain including enhanced neurogenesis in the subventricular zone during pregnancy. The resultant increase in olfactory interneurons may be required for altered processing of olfactory cues during the establishment of maternal behavior. Pheromones act through olfactory pathways to exert powerful effects on behavior in rodents and also affect prolactin secretion. Hence, this study aimed to investigate the effect of male pheromones on neurogenesis and maternal behavior in female mice. Virgin female mice were housed individually or in split-cages where they had pheromonal but not physical contact with a male. Maternal behavior was assessed in a foster pup retrieval paradigm. Some mice were injected with bromodeoxyuridine, and the labeled cells visualized using immunohistochemistry. The data show that exposure to male pheromones, for a duration equivalent to a murine pregnancy, advanced maternal behavior in both virgin and postpartum female mice. The pheromone action was dependent on prolactin and ovarian steroids, and was associated with increased cell proliferation in the subventricular zone and subsequent increases in new neurons in the olfactory bulb. Moreover, the effect of pheromones on both cell proliferation and maternal behavior could be induced solely through administration of exogenous prolactin to mimic the pheromone-induced changes in prolactin secretion. The data suggest that male pheromones induce a prolactin-mediated increase in neurogenesis in female mice, resulting in advanced maternal behavior.
催乳素是产后母性行为快速启动所必需的，它能诱导母鼠大脑发生适应性变化，包括孕期脑室下区神经发生增强。嗅觉中间神经元数量的增加可能是母性行为建立过程中嗅觉线索处理改变所必需的。信息素通过嗅觉通路对啮齿动物的行为产生强大影响，同时也影响催乳素的分泌。因此，本研究旨在探讨雄性信息素对雌性小鼠神经发生和母性行为的影响。将未交配的雌性小鼠单独饲养或置于分隔笼中，使其与雄性小鼠有信息素接触但无身体接触。在寄养幼崽取回范式中评估母性行为。部分小鼠注射溴脱氧尿苷，并用免疫组织化学法观察标记细胞。数据显示，暴露于雄性信息素相当于小鼠孕期的时长，可使未交配和产后雌性小鼠的母性行为提前。信息素的作用依赖于催乳素和卵巢类固醇，并与脑室下区细胞增殖增加以及随后嗅球新神经元数量增加有关。此外，仅通过给予外源性催乳素来模拟信息素诱导的催乳素分泌变化，就能诱导信息素对细胞增殖和母性行为的影响。数据表明，雄性信息素可诱导雌性小鼠催乳素介导的神经发生增加，从而导致母性行为提前。
