Effects of 5-HT2B, 5-HT3 and 5-HT4 receptor antagonists on gastrointestinal motor activity in dogs

Figure 4 5-hydroxytryptamine 3 receptor antagonists on normal colonic motor activity. A: Typical effect of the 5-hydroxytryptamine (5-HT) 3 receptor antagonist. The 5-HT3 receptor antagonist inhibited phase III of the interdigestive motor complex at the antrum and whole colonic motor activity; B: The inhibition ratio compared with before 5-HT3 receptor antagonist administration. The inhibitory effect of the 5-HT3 receptor antagonist was dose dependent in the proximal colon (ICS-C2). At a dose of 0.3 mg/kg, whole colonic motor activity was inhibited significantly. Values are mean ± SE. ^aP < 0.05 vs control (0 mg/kg). ICS: Ileocecal sphincter; C1-4: Colon 1-4.