Liu Xiuhong, Wang Yipeng, Cheng Lihua, Song Yuzhu, Lai Ren
Key Laboratory of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, Life Sciences College of Nanjing Agricultural University, Nanjing, Jiangsu 210095, China.
Peptides. 2007 Aug;28(8):1540-4. doi: 10.1016/j.peptides.2007.07.006. Epub 2007 Jul 14.
Many neuroendocrine peptides that are distributed in amphibian gastrointestinal tract and central nervous system are also found in amphibian skins, and these peptides are classified into skin-gut-brain triangle peptides, such as bombesins, gastrin-releasing peptides. Cholecystokinins (CCKs) are neuroendocrine peptides known for their production in the gastrointestinal tract and central nervous system of mammalians. Several CCKs have been identified from two amphibians, Rana catesbeiana and Xenopus laevis. These amphibian CCKs are found to be express in brain and in the gastrointestinal tract, but not in skin. In the current report, a cholecystokinin (CCK) isoform was identified from skin secretions of the frog, Rana nigrovittata. Its amino acid sequence is RVDGNSDQKAVIGAMLAKDLQTRKAGSSTGRYAVLPNR PVIDPTHRINDRDYMGWMDF, which is the same with that of CCK from R. catesbeiana. Four different cDNAs (GenBank accession nos. EF608063-6) encoding CCK precursors were cloned from the cDNA library of the skin of R. nigrovittata. The present data demonstrated that amphibian CCK could also be expressed in gastrointestinal tract, central nervous system and skin as other amphibian skin-gut-brain triangle peptides.
许多分布于两栖动物胃肠道和中枢神经系统的神经内分泌肽在两栖动物皮肤中也有发现，这些肽被归类为皮肤-肠道-脑三角肽，如蛙皮素、胃泌素释放肽。胆囊收缩素（CCK）是一种神经内分泌肽，因其在哺乳动物胃肠道和中枢神经系统中的产生而为人所知。已从两种两栖动物，即牛蛙和非洲爪蟾中鉴定出几种CCK。这些两栖动物的CCK被发现表达于脑和胃肠道，但不在皮肤中。在本报告中，从黑斑侧褶蛙的皮肤分泌物中鉴定出一种胆囊收缩素（CCK）同工型。其氨基酸序列为RVDGNSDQKAVIGAMLAKDLQTRKAGSSTGRYAVLPNR PVIDPTHRINDRDYMGWMDF，与牛蛙的CCK相同。从黑斑侧褶蛙皮肤的cDNA文库中克隆出四个编码CCK前体的不同cDNA（GenBank登录号EF608063-6）。目前的数据表明，两栖动物的CCK也可像其他两栖动物皮肤-肠道-脑三角肽一样在胃肠道、中枢神经系统和皮肤中表达。
