Distribution of a-MSH-like immunoreactive cells in the nervous system, Hatschek’s pit and other tissues of amphioxus, Branchiostoma belcheri  

Distribution of α-MSH-like immunoreactive cells in the nervous system,Hatschek's pit and other tissues of amphioxus,Branchiostoma belcheri

作　　者：Yongqiang Fang Youzhu Weng Haixia Song 

机构地区：[1]The Third Institute of Oceanography, State Oceanic Administration, Xiamen 361005, China

出　　处：《Progress in Natural Science:Materials International》2008年第4期463-468,共6页自然科学进展·国际材料（英文版）

基　　金：the National Natural Science Foundation of China（Grant No.30470224）.

摘　　要：Immunohistochemical localization of α-melanocyte-stimulating hormone （α-MSH） in the nervous system, Hatschek＇s pit and other tissues of amphioxus （Branchiostorna belcheri） was performed using the antibody against synthetic α-MSH. The results revealed that α-MSH-like immunoreactive cells were distributed at the dorsal side and ventral side of brain vesicle, the dorsal side and the surrounding of nerve tube, and in the epithelial cells of Hatschek＇s pit, the zone 1, 3, and 6 of endostyle and gut. The immunoreactive substance was also found in the primary oocytes of the small and large growth stage of ovary and early stage spermatogenic cells in testis. These findings indicate that α-MSH is an ancient and highly conserved hormone and it is extensively distributed in amphioxus. Although Hatschek＇s pit in amphioxus does not have a structure of the intermediate lobe of vertebrate adenohypophysis, it has already hosted α-MSH-like endocrine cells, implying that the functional differentiation of α-MSH-like cells occurred earlier than the differentiation of the tissue structure. The results of the present study provided a new evidence for the endocrinology of Hatschek＇s pit and for the origin and evolution of vertebrate adenohypophysis.Immunohistochemical localization of a-melanocyte-stimulating hormone (a-MSH) in the nervous system, Hatschek's pit and other tissues of amphioxus (Branchiostoma belcheri) was performed using the antibody against synthetic a-MSH. The results revealed that a-MSH-like immunoreactive cells were distributed at the dorsal side and ventral side of brain vesicle, the dorsal side and the surrounding of nerve tube, and in the epithelial cells of Hatschek's pit, the zone 1, 3, and 6 of endostyle and gut. The immunoreactive substance was also found in the primary oocytes of the small and large growth stage of ovary and early stage spermatogenic cells in testis. These findings indicate that a-MSH is an ancient and highly conserved hormone and it is extensively distributed in amphioxus. Although Hatschek's pit in amphioxus does not have a structure of the intermediate lobe of vertebrate adenohypophysis, it has already hosted a-MSH-like endo- crine cells, implying that the functional differentiation of a-MSH-like cells occurred earlier than the differentiation of the tissue structure. The results of the present study provided a new evidence for the endocrinology of Hatschek's pit and for the origin and evolution of vertebrate adenohypophysis.

关 键 词：Amphioxus （Branchiostoma belcherO Alpha-melanocyte-stimulating hormone （ct-MSH） Hatschek＇s pit Nervous system IMMUNOHISTOCHEMISTRY 

分 类 号：Q959.4[生物学—动物学]