Anatomical distribution and cellular basis for high levels of aromatase activity in the brain of teleost fish: Aromatase enzyme and mRNA expression identify glia as source
Anatomical distribution and cellular basis for high levels of aromatase activity in the brain of teleost fish: Aromatase enzyme and mRNA expression identify glia as source
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DOI：
10.1523/jneurosci.21-22-08943.2001
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发表时间：
2001-11-15
影响因子：
5.3
通讯作者：
Bass, AH
中科院分区：
文献类型：
--
作者：
Forlano, PM;Deitcher, DL;Bass, AH
虽然硬骨鱼的脑芳香化酶活性水平高于任何其他脊椎动物组，但其功能仍然是推测性的，没有研究确定其细胞基础。先前的一项研究确定了芳香化酶活性的声音鱼，plainfin海军军官候补生（Porichthys notatus），并发现最高水平的端脑和较低水平的声波后脑，这是二态性之间和（男性）性别内。我们现在已经本地化的芳香化酶在海军学员大脑中的细胞，通过免疫细胞化学使用硬骨鱼特异性芳香化酶抗体和原位杂交使用海军学员特异性芳香化酶探针。芳香化酶的免疫反应性和mRNA杂交信号是一致的芳香化酶活性在不同的大脑区域的相对水平：集中在二形的声音运动核，在一个带的中脑导水管周围灰质下方，在下丘脑的脑室区域，和最高水平的端脑，特别是在视前区和脑室区。令人惊讶的是，双标记免疫荧光并没有显示芳香化酶免疫反应共定位在神经元，而是在整个大脑的放射状胶质细胞。这是第一项研究，以确定芳香化酶的表达大部分，如果不是全部，在神经胶质细胞在正常，而不是脑损伤依赖性条件。芳香化酶在硬骨鱼类中的丰度可能代表了一种与持续神经发生有关的适应，这种适应在鱼类中贯穿于个体的一生。芳香化酶在性间和性内双态性发声运动回路中的定位进一步暗示了在替代性男性生殖表型的表达中的功能，并且更普遍地，在特定脑核团的自然个体变异的发展中的功能。
Although teleost fish have higher levels of brain aromatase activity than any other vertebrate group, its function remains speculative, and no study has identified its cellular basis. A previous study determined aromatase activity in a vocal fish, the plainfin midshipman (Porichthys notatus), and found highest levels in the telencephalon and lower levels in the sonic hindbrain, which was dimorphic between and within (males) sexes. We have now localized aromatase-containing cells in the midshipman brain both by immunocytochemistry using teleost-specific aromatase antibodies and by in situ hybridization using midshipman-specific aromatase probes. Aromatase-immunoreactivity and mRNA hybridization signal are consistent with relative levels of aromatase activity in different brain regions: concentrated in the dimorphic sonic motor nucleus, in a band just beneath the periaqueductal gray in the midbrain, in ventricular regions in the hypothalamus, and highest levels in the telencephalon especially in preoptic and ventricular areas. Surprisingly, double-label immunofluorescence does not show aromatase-immunoreactive colocalization in neurons, but instead in radial glia throughout the brain. This is the first study to identify aromatase expression mostly, if not entirely, in glial cells under normal rather than brain injury-dependent conditions. The abundance of aromatase in teleosts may represent an adaptation linked to continual neurogenesis that is known to occur throughout an individual's lifetime among fishes. The localization of aromatase within the intersexually and intrasexually dimorphic vocal-motor circuit further implies a function in the expression of alternative male reproductive phenotypes and, more generally, the development of natural, individual variation of specific brain nuclei.