Brus Maïna, Trouillet Anne-Charlotte, Hellier Vincent, Bakker Julie
Laboratory of Neuroendocrinology, Groupe Interdisciplinaire de Génoprotéomique Appliquée (GIGA) Neurosciences, University of Liège, Liège, Belgium.
J Neurochem. 2016 Aug;138(3):457-68. doi: 10.1111/jnc.13677. Epub 2016 Jul 14.
Odors processed by the main and accessory olfactory bulbs (MOB, AOB) are important for sexual behavior. Interestingly, both structures continue to receive new neurons during adulthood. A role for olfactory neurogenesis in sexual behavior in female mice has recently been shown and gonadal hormones such as estradiol can modulate adult neurogenesis. Therefore, we wanted to determine the role of estradiol in learning the odors of sexual partners and in the adult neurogenesis of female aromatase knockout mice (ArKO), unable to produce estradiol. Female wild-type (WT) and ArKO mice were exposed to male odors during 7 days, and olfactory preferences, cell proliferation, cell survival and functional involvement of newborn neurons were analyzed, using BrdU injections, in combination with a marker of cell activation (Zif268) and neuronal fate (doublecortin, NeuN). Behavioral tasks indicated that both WT and ArKO females were able to discriminate between the odors of two different males, but ArKO mice failed to learn the familiar male odor. Proliferation of newborn cells was reduced in ArKO mice only in the dentate gyrus of the hippocampus. Olfactory exposure decreased cell survival in the AOB in WT females, suggesting a role for estradiol in a structure involved in sexual behavior. Finally, newborn neurons do not seem to be functionally involved in the AOB of ArKO mice compared with WT, when females were exposed to the odor of a familiar male, suggesting that estradiol-induced neurogenesis in the AOB is required for the learning of the male odor in female mice. Aromatase knockout mice (ArKO) presented deficits in olfactory preferences without affecting their olfactory discrimination abilities, and showed no functional involvement of newborn neurons in the accessory olfactory bulb (AOB) in response to the odor of a familiar male. These results suggest that estradiol-induced neurogenesis in the female AOB is required for the learning of the male odor.
由主嗅球和副嗅球（MOB，AOB）处理的气味对性行为很重要。有趣的是，这两个结构在成年期仍会持续接收新的神经元。最近已表明嗅觉神经发生在雌性小鼠性行为中起作用，而诸如雌二醇等性腺激素可调节成年神经发生。因此，我们想确定雌二醇在学习性伴侣气味以及在无法产生雌二醇的雌性芳香化酶基因敲除小鼠（ArKO）的成年神经发生中的作用。雌性野生型（WT）和ArKO小鼠在7天内接触雄性气味，使用BrdU注射结合细胞激活标记物（Zif268）和神经元命运标记物（双皮质素，NeuN）分析嗅觉偏好、细胞增殖、细胞存活以及新生神经元的功能参与情况。行为任务表明，WT和ArKO雌性小鼠都能够区分两种不同雄性的气味，但ArKO小鼠无法学习熟悉的雄性气味。仅在海马体的齿状回中，ArKO小鼠的新生细胞增殖减少。嗅觉暴露降低了WT雌性小鼠AOB中的细胞存活，这表明雌二醇在参与性行为的结构中起作用。最后，当雌性小鼠接触熟悉雄性的气味时，与WT相比，ArKO小鼠的新生神经元似乎在AOB中没有功能参与，这表明AOB中雌二醇诱导的神经发生是雌性小鼠学习雄性气味所必需的。芳香化酶基因敲除小鼠（ArKO）在嗅觉偏好方面存在缺陷，但不影响其嗅觉辨别能力，并且对熟悉雄性的气味没有显示出新生神经元在副嗅球（AOB）中的功能参与。这些结果表明，雌性AOB中雌二醇诱导的神经发生是学习雄性气味所必需的。
