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

Figure 3 Increased serotonin receptor 2B and transient receptor potential vanilloid type 1 levels in the irritable bowel syndrome with diarrhea group. A: Immunohistochemical staining revealed the expression of the serotonin receptor 2B (5-HT_2B receptor) in the colon tissue in irritable bowel syndrome with diarrhea (IBS-D) rats and normal control rats; Magnification 20 ×; B: Expression of 5-HT_2B receptor protein in the colonic mucosa layer of the IBS-D group and normal control group; C: Expression of 5-HT_2B receptor protein in the colonic muscular layer of the IBS-D group and normal control group; D: Levels of 5-HT_2B receptor mRNA in the colonic mucosa layer from the IBS-D group and normal control group; E: Levels of 5-HT_2B receptor mRNA in the colonic muscular layer from the IBS-D group and normal control group; F: Immunohistochemical staining showing the expression of transient receptor potential vanilloid type 1 (TRPV1) in the colon tissue in IBS-D rats and normal control rats. Magnification 20 ×; G: Levels of TRPV1 mRNA in the colonic mucosa layer from the IBS-D group and normal control group; H: Levels of TRPV1 mRNA in the colonic muscular layer from the IBS-D group and normal control group. ^aP < 0.05, ^cP < 0.001. IBS-D: Irritable bowel syndrome with diarrhea; 5-HT_2B: Serotonin receptor 2B; TRPV1: Transient receptor potential vanilloid type 1.