Studies On Intestinal Histology And Distribution Of5-HT Of Eriocheir Sinensis

Chinese mitten crab, Eriocheir sinensis, belonging to Decapoda、Reptantia、Grapsidae、Eriocheir, is a unique freshwater crabs in china, commonly known as crab.The crab becomes a breeding object because of its delicious and nutritious in recentyears. And understand its digestive physiology has an important role to the healthybreeding. This research mainly around the intestinal as its intestinal tissue structureare closely related to the physiological functions，and the intestinal mucosa epithelialcells played a decisive role in the physiological functions of intestinal，clarify theintestinal histology and intestinal epithelial cell types is important for the study oferiocheir sinensis digestive physiology. Serotonin (5-hydroxytryptamine,5-HT) is akind of single amine neurotransmitter, plays an important role in regulating thereproductive, molting, behavior, digestion, absorption and metabolism of crustaceans.5-HT is widely distributed in the digestive tract of all kinds of animals, is closelyrelated to the digestive function. Tryptophan hydroxylase (TPH) is the rate-limitingenzyme for5-HT biosynthesis and can be used to identify5-HT as a marker, so itbecomes the research object of this study. This study mainly research the histologicalstructure of intestinal tract, the intestinal epithelial cells types and the distribution of5-HT and TPH1in the intestinal tract of Eriocheir sinensis, to learn more about theintestinal tissue structure and the effects of5-HT on intestinal physiological function,in order to provide the theory basis for the research on the digestive function ofcrustaceans and the effects of biogenic amines on the digestive physiology.This research mainly divided into three parts, respectively is:1. Studies on intestinal histology of Eriocheir sinensisThese experiments studied on the intestinal tissue structure of juvenile and adultcrab through adopt the method of vivisection and HE-staining, the results are asfollows:1) The results of vivisection is that the intestinal tract includes the midgut, the hindgutampulla and hidgut, and the midgut includes a pair of front coecum and a posteriorcoecum, there has no difference on juvenile and adult crab.2) There four layers can be identified in intestinal tissue structure includes the mucosa,submucosa, muscularis and adventitia.3) The intestinal villus is more intensive in midgut of adult crab than juvenile crab.4) Tront coecum and posterior coecum were all composed of mucosal epithelial cellsthat similar to the midgut，but the nucleus has strong basophilia，and the lumen haveno intestinal villus. 5) The front coecum connected with the front of midgut and the hepatopancreas，butthe Lumen structure is different from Liver tubules.6) Many tubular structures were found in the outer membrane connective tissue ofadult crab, but not found in juvenile crab7) Submucosa of hidgut is more developed than midgut and has the structure ofhindgut gland, and the hidgut is more developed in adult crab.2. Discrimination on the intestinal epithelial cell types of Eriocheir sinensisThese experiments studied on the discrimination of intestinal epithelial cell typesof crab through adopt the method of PAS-staining and immunohistochemistry, theresults are as follows:1) There is no goblet cell in the intestinal epithelial cells of the midgut and hidgut.2) The intestinal endocrine cells distributed between the intestinal epithelial cells ofthe midgut and hidgut.3) Paneth cells diatributed in the hindgut gland, but not found in the midgut.3. Distribution of5-HT and TPH1in the intestinal of Eriocheir sinensisThis experiment studied on the distribution of5-HT and TPH1in the intestinal ofcrab through adopts the method of immunohistochemistry, the results are as follows:1)5-HT can be detected by immunolocalization in the midgut, the hindgut ampullaand hidgut. In the midgut,5-HT is mainly distributed in the nucleus of mucosalepithelial cells and adventitia. In the hindgut ampulla,5-HT was widely distributed inthe nucleus of mucosal epithelial cells and peripheral connective tissue. In the hidgut,TPH is mainly found in the nucleus of mucosal epithelial cells and adventitia.2) TPH1can be detected by immunolocalization in the midgut, the hindgut ampullaand hidgut. In the midgut, TPH1is mainly distributed in the nucleus of mucosalepithelial cells. In the hindgut ampulla, TPH were widely distributed in the nucleus ofmucosal epithelial cells close to the midgut and the cytoplasm of mucosal epithelialcells close to the hidgut，and peripheral connective tissue. In the hidgut, TPH ismainly found in the cytoplasm of mucosal epithelial cells.