Testosterone aromatization into estrogens in the preoptic area (POA) is critical for the activation of male sexual behavior in many vertebrates. Yet, the cellular mechanisms mediating actions of neuroestrogens on sexual behavior remain largely unknown. We investigated in male and female Japanese quail by dual‐label fluorescent in situ hybridization (FISH) whether aromatase‐positive (ARO) neurons express glutamic acid decarboxylase 67 (GAD67), the rate‐limiting enzyme in GABA biosynthesis. ARO cells and ARO cells double labeled with GAD67 (ARO‐GAD67) were counted at standardized locations in the medial preoptic nucleus (POM) and the medial bed nucleus of the stria terminalis (BST) to produce three‐dimensional distribution maps. Overall, males had more ARO cells than females in POM and BST. The number of double‐labeled ARO‐GAD67 cells was also higher in males than in females and greatly varied as a function of the specific position in these nuclei. Significant sex differences were however present only in the most caudal part of POM. Although both ARO and GAD67 were expressed in the VMN, no colocalization between these markers was detected. Together, these data show that a high proportion of estrogen‐synthesizing neurons in POM and BST are inhibitory and the colocalization of GAD67 with ARO exhibits a high degree of anatomical specificity as well as localized sex differences. The fact that many preoptic ARO neurons project to the periaqueductal gray in male quail suggests possible mechanisms through which locally produced estrogens could activate male sexual behavior.

中文翻译：

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雄性和雌性鹌鹑脑中芳香酶神经元和 GAD67 的性别分化和神经解剖学特异性共表达。

在视前区 (POA) 中睾酮芳香化为雌激素对于激活许多脊椎动物的雄性性行为至关重要。然而，调节神经雌激素对性行为作用的细胞机制在很大程度上仍然未知。我们通过双标记荧光原位杂交 (FISH) 在雄性和雌性日本鹌鹑中研究了芳香酶阳性 (ARO) 神经元是否表达谷氨酸脱羧酶 67 (GAD67)，这是 GABA 生物合成的限速酶。在内侧视前核 (POM) 和终纹内侧床核 (BST) 的标准化位置对 ARO 细胞和 ARO 细胞双标记 GAD67 (ARO-GAD67) 进行计数，以生成三维分布图。总体而言，在 POM 和 BST 中，雄性比雌性具有更多的 ARO 细胞。双标记 ARO-GAD67 细胞的数量在男性中也高于女性，并且作为这些细胞核中特定位置的函数而变化很大。然而，显着的性别差异仅存在于 POM 的最尾部。尽管 ARO 和 GAD67 都在 VMN 中表达，但未检测到这些标记之间的共定位。总之，这些数据表明 POM 和 BST 中高比例的雌激素合成神经元是抑制性的，GAD67 与 ARO 的共定位表现出高度的解剖学特异性以及局部性别差异。许多视前 ARO 神经元投射到雄性鹌鹑的导水管周围灰质的事实表明，局部产生的雌激素可以激活雄性性行为的可能机制。