Serotonin receptor 2B induces visceral hyperalgesia in rat model and patients with diarrhea-predominant irritable bowel syndrome

Figure 4 RS12-7445 decreased the visceral sensitivity and serotonin receptor 2B levels in irritable bowel syndrome with diarrhea rats. A: The irritable bowel syndrome with diarrhea (IBS-D) + Vehicle group had significantly greater abdominal withdrawal reflex scores than did the IBS-D + RS-127445 group with the same colorectal distension (CRD) pressure; B: The IBS-D + Vehicle group had significantly reduced threshold pressure than did the IBS-D + RS-127445 group with the same CRD pressure; C: Immunohistochemical staining showing the expression of the serotonin receptor 2B receptor in the colon mucosa layer and colon muscular layer of each group. Magnification 20 ×; ^aP < 0.05, ^bP < 0.01, ^cP < 0.001. IBS-D: Irritable bowel syndrome with diarrhea; 5-HT_2B: Serotonin receptor 2B; AWR: Abdominal withdrawal reflex.