6种胃肠激素样内分泌细胞在细鳞鲑消化道的定位

Identification and location research of six types of gastrointestinal hormone endocrine cells in digestive tract samples of Brachymystax lenok

采用免疫细胞化学ABC方法,选择5-羟色胺(5-hydroxytryptamine,5-HT)、生长抑素(somatostatin,SS)、胰多肽(pancreatic polypeptide,PP)、胃泌素(gastrin,GAS)和P物质(substance P,SP)6种特异性哺乳类胃肠激素抗血清,对不同年龄段(1龄、2龄和3龄)细鳞鲑(Brachymystax lenok)的消化道内分泌细胞进行了免疫细胞化学定位研究。结果表明,仅在食管、胃贲门、胃体和胃幽门检出有5-HT、SS和PP阳性细胞的分布(除1龄鱼食道),且这3种内分泌细胞均大量定位于胃部;在前肠、中肠、后肠和直肠中均未检测到这3种内分泌细胞的阳性反应。在3个年龄段的细鳞鲑胃肠各部位均未检测到GAS、GLU和SP阳性细胞。细鳞鲑的5-HT、SS和PP与其他有胃鱼类的内分泌细胞一样,可分为2种类型,即开放型和闭合型,这类细胞主要通过腔分泌和旁分泌两种方式释放激素。5-HT、SS和PP这3种细胞在1龄幼鱼消化道内就已经发育成熟,其对胃肠道活动的调节作用已经与成鱼没有差别,细胞的分布密度随着细鳞鲑的年龄增长不断增加。本研究揭示了不同生长阶段细鳞鲑消化道中这6种胃肠激素内分泌细胞的发育特征,并阐明了这些胃肠激素细胞在细鳞鲑幼鱼消化道的分布、形态以及生理作用。

Brachymystax lenok is an important commercial fish that are now at risk of extinction due to over exploitation and environmental pollution in China. The development of culture techniques for supplementation would benefit from a better understanding of the endocrine cells in digestive tract and their role in ingestion, digestion, and absorption of food. We documented the localization, regional distribution, and relative frequency of endocrine cells in the digestive tract of B. lenok. We used 6 mammalian antisera, including 5-hydroxytrptamine（5-HT）, somatostatin（SS）,by immunohistochemical SABC pancreatic polypeptide（PP）, gastrin （GAS） and substance P（SP） to locate the endocrine cells in 1-, 2-, and 3-year-old individuals . 5-HT immunoreactive（-ir）, SS-ir, and PP-ir cells were detected in the esophagus and throughout the stomach, including the stomachus cardiacus, stomachus fundus, and stomachus pyloricus of all age classes （except the esophagus of one-year old fish）. The highest density of 5-HT-ir and SS-ir cells was in stomachus fundus of three-year old B. lenok（P〈O.05）. The density of PP-ir cells was significantly higherine cells were not detected in the foregut, midgut, hindgut, or rectum. GAS-ir cells, GLU-ir cells, and SP-r in the stomachus pyloricus of 2-year-old individuals than in 1- and 3-year-old fish （P〈0.05）. However, these three kinds of endocir cells were not detected in any part of the digestive tract of 1-3-year-old B. lenok. As the endocrine cells of other teleosts, the 5-HT-ir, SS-ir, and PP-ir cells ofB. lenok were divided into two types： open type with cytoplasmic process and closed type without a cytoplasmic process. In summary, 5-HT-ir, SS-ir, and PP-ir cells mature in the gastrointestinal tract orB. lenok after 1 year, and have the same regulatory function at this time as in adults. The density of these cell increased with age.