芳香化酶在文昌鱼神经系统、哈氏窝和性腺特异性定位:原位杂交和免疫细胞化学研究(英文)

Localization of aromatase in the nervous system,Hatschek's pit and gonad of amphioxus by in situ hybridization and immunocytochemistry

芳香化酶活性发现在脊椎动物脑、脑垂体和性腺中 ,但在文昌鱼脑和哈氏窝的组织特异性定位尚无可利用资料。本文用免疫细胞化学和原位杂交技术 ,首次发现芳香化酶活性组织特异性定位在幼年和性腺发育不同时期雌、雄文昌鱼神经系统 (脑和脊髓 )、轮器、哈氏窝和性腺中。芳香化酶蛋白和转录物在前脑、中脑、脊髓、轮器和哈氏窝十分丰富 ,而后脑、早期卵巢和精巢不够丰富 ;没有芳香化酶表达的部位是哈氏窝另两种细胞 (不规则形细胞和带纤毛粘液细胞 )以及成熟卵巢和精巢 ;芳香化酶免疫活性物质分布在胞质 ,核为阴性。芳香化酶在文昌鱼神经系统、哈氏窝和性腺的分布模式与低等脊椎动物中的分布模式极为类似 ,尤其是芳香化酶在脑内调节哈氏窝分泌活动的神经内分泌中枢表达 ,并形成类似脊椎动物的文昌鱼原始的脑 -芳香化酶调节系统。这些结果有力地证明 ,文昌鱼脑和哈氏窝高水平的芳香化酶活性像在其它脊椎动物中一样 ,对局部介导睾酮芳香化起着关键作用 ,同时还可能影响脑

Aromatase activity has been found in the brain and pituitary as well as gonads of vertebrates, but no information is available on the specific localization in the brain and Hatschek's pit (primitive pituitary) of amphioxus ( Branchiostoma belcheri ). Using immunocytochemistry and in situ hybridization, we studied definitive tissue specific localization of aromatase in the nervous system (brain and spinal cord), wheel organ, Hatschek's pit and gonads at young and adult female and male amphioxus at different stages of gonadal development. Aromatase protein and its mRNA were abundant in the forebrain, midbrain, spinal cord, wheel organ and Hatschek's pit, but not abundant in the hindbrain or early ovary and testis. No aromatase expression was detected in both irregular shaped cells and ciliated mucous cells in the Hatschek's pit or in the mature ovary and testis. Aromatase immunoreactive material was distributed in the cytoplasm with negative nuclei. The aromatase distribution pattern in the nervous system, Hatschek's pit and gonad closely is similar to that observed in vertebrates. Especially, aromatase expression was found in the neuroendocrine center regulating the secretory activity of Hatschek's pit. Therefore, amphioxus has a primitive brain aromatase regulatory system similar to that of vertebrates. These results strongly suggest that the high level of aromatase activity in the brain and Hatschek's pit of amphioxus may play a key role in mediating aromatization of local in situ synthetic testosterone, and influence the brain aromatase system, which participates in regulating the secretory activity of Hatschek's pit.