Figure 1: Experimental setup. The organ bath is composed of an inside chamber and an outside chamber. The Krebs solution contained in the small chamber was maintained constant at 37°C by circulating hot water in the big chamber using a heating machine. The intestinal segment was placed in the small organ bath in the Krebs solution. The intestinal distension was applied by a pump and the longitudinal length was set by a micromanipulator. The three-channel pressure probe was used to measure the pressures. The diameter changes of the intestinal segments were videotaped through a stereomicroscope.