The Expression Of5-hydroxytryptamine Type Three Receptor In Gastrointestinal Tract Of Rats With Slow Transit Constipation

ObjectiveTo investigate the expression of5-HT3receptor in the stomach、small intestine andcolon tissues of rats with slow transit constipation(STC),and explore its function in thepathogenesis of STC.MethodsTaking twenty-four healthy Wistar rats to devide into experimental group and controlgroup. Each experimental group was given diphenoxylate (8mg/kg) everyday to make itinto slow transit constipation model, while the control group were given normal saline.The defecation, stool weight and body weight of rats were recorded every five days.Using activated charcoal to determinate the time of gastrointestinal transit one weekafter stopping the gavage of diphenoxylate for90days. Selecting antrum, smallintestine and colon tissue when rats were sacrificed.Using real-time Polymerase chainreaction(RT-PCR)to detect the expression of5-HT3receptor in stomach、small intestineand colon of rats.ResultsThe daily defecation of experimental group were obviously less than that in the controlgroup,the mean weight of each defecation in experimental group was obviously largerthan that in control group, the discharge time of the first melena tarry stool inexperimental group was obviously longer than that in control group,we can judge themodel was successful.5-HT3receptor was specifically amplified by RT-PCR.Theexpression of5-HT3receptor in stomach、small intestine and colon tissues of STC was lower than those normal tissues（0.744±0.065、P<0.05；0.294±0.044、P<0.001；0.16±0.027、P<0.001）.ConclusionThe expression level of5-HT3receptor is decreased in stomach、small intestine andcolon tissues of STC model rats,which may contribute to the pathogenesis of STC.