Low Katelyn L, Ma Chunqi, Soma Kiran K
Department of Psychology and The Djavad Mowafaghian Centre for Brain Health (KLL, CM, KKS), The University of British Columbia, Vancouver, British Columbia, Canada.
Department of Zoology (KLL, KKS), The University of British Columbia, Vancouver, British Columbia, Canada.
J Histochem Cytochem. 2017 May;65(5):295-308. doi: 10.1369/0022155417694870. Epub 2017 Mar 1.
Research on neural androgen receptors (ARs) has traditionally focused on brain regions that regulate reproductive and aggressive behaviors, such as the hypothalamus and amygdala. Although many cells in the prefrontal cortex (PFC) also express ARs, the number of ARs per cell appears to be much lower, and thus, AR immunostaining is often hard to detect and quantify in the PFC. Here, we demonstrate that biotin tyramide signal amplification (TSA) dramatically increases AR immunoreactivity in the rat brain, including critical regions of the PFC such as the medial PFC (mPFC) and orbitofrontal cortex (OFC). We show that TSA is useful for AR detection with both chromogenic and immunofluorescent immunohistochemistry. Double-labeling studies reveal that AR+ cells in the PFC and hippocampus are NeuN+ but not GFAP+ and thus primarily neuronal. Finally, in gonadally intact rats, more AR+ cells are present in the mPFC and OFC of males than of females. Future studies can use TSA to further examine AR immunoreactivity across ages, sexes, strains, and different procedures (e.g., fixation methods). In light of emerging evidence for the androgen regulation of executive function and working memory, these results may help understand the distribution and roles of ARs in the PFC.
对神经雄激素受体（ARs）的研究传统上集中在调节生殖和攻击行为的脑区，如下丘脑和杏仁核。虽然前额叶皮质（PFC）中的许多细胞也表达ARs，但每个细胞中的ARs数量似乎要低得多，因此，在PFC中AR免疫染色往往难以检测和定量。在这里，我们证明生物素酪胺信号放大（TSA）显著增加了大鼠脑中的AR免疫反应性，包括PFC的关键区域，如内侧前额叶皮质（mPFC）和眶额皮质（OFC）。我们表明TSA对显色和免疫荧光免疫组织化学检测AR均有用。双标记研究表明，PFC和海马中的AR+细胞是NeuN+而非GFAP+，因此主要是神经元。最后，在性腺完整的大鼠中，雄性mPFC和OFC中的AR+细胞比雌性更多。未来的研究可以使用TSA进一步检查不同年龄、性别、品系和不同程序（如固定方法）下的AR免疫反应性。鉴于雄激素对执行功能和工作记忆调节的新证据，这些结果可能有助于理解ARs在PFC中的分布和作用。
