中华绒螯蟹(Eriocheir sinensis)肠道和肝胰腺5-羟色胺(5-HT)和5-羟色胺受体2(5-HTR2)的定位研究

5-HT AND 5-HTR2-LIKE IMMUNOREACTIVE CELLS IN INTESTINE AND HEPATOPANCREAS OF CHINESE MITTEN CRAB ERIOCHEIR SINENSIS

肠道和肝胰腺是中华绒螯蟹(Eriocheir sinensis)重要的消化器官,本文运用组织学技术测量了中肠和后肠长度,并对肠道长与体长进行相关性分析。应用免疫组化技术对5-HT和5-HT受体2进行组织定位和计数。结果表明:(1)中华绒螯蟹的肠道长与体长接近,两者之间呈极显著正相关(P<0.01)。后肠长度约为中肠的2倍;(2)5-HT和5-HT受体2在中肠和后肠中的组织定位和数量相似,均分布于黏膜上皮细胞间和肌层与外膜交界处,亦见于后肠的固有膜和黏膜下层与肌层交界处,在肠球外膜中也有大量分布;(3)5-HT和5-HT受体2阳性物质在肝胰腺的四种细胞的胞核中均有分布,在F细胞的胞质中也有分布。5-HT和5-HT受体2在中华绒螯蟹肠道和肝胰腺组织中的分布规律一致,表明中华绒螯蟹消化道5-HT发挥生理功能可能与5-HT受体2有关。此外,5-HT和5-HT受体2在后肠近肌细胞分布的特点可能与肠道收缩有关。后肠在中华绒螯蟹消化生理中的作用应引起重视。

To understand the digestive physiology of the intestine and hepatopancreas, we measured the lengths of midgut and hindgut of Eriocheir sinensis, analysed the correlation between intestine length and body length, and observed the immunolocation of 5-hydroxytryptamine（5-HT） and 5-HT receptor2（5-HTR2） positive cells in these organs by immunohistochemical method. Results show that the length of intestine was similar to that of body, and the correlation between the lengths of intestine and body was significant（P〈0.01）. The length of hindgut was about two-fold of the length of midgut. The distribution and number of 5-HT and 5-HTR2 positive cells in midgut were similar to those of hindgut. 5-HT and 5-HTR2 immunoreactive cells distributed mainly among the epithelium of the intestinal mucosa and between muscle layer and tunica adventitia of midgut and hindgut. These immunoreactive cells were also detected in lamina propria and between submucosa and muscle layer of hindgut and tunica adventitia of intestine ball. In addition, 5-HT and 5-HTR2 were also localized in the nuclei of four hepatopancreas cells（including E-, R-, F-, and B-cell）. Among these hepatopancreas cells, the nuclei and cytoplasm of F-cell showed strong 5-HT and 5-HTR2 reaction. These findings indicate, for the first time to our knowledge, a probable close link between 5-HT and 5-HTR2 in E. sinensis digestive system, and 5-HT and 5-HTR2 immunoreactive cells that reside adjacent to intestinal smooth muscle might be involved in the regulation of the contractile state of intestinal smooth muscle. Therefore, the digestive physiology of E. sinensis hindgut should be paid with more attention.