Tissue Bath for Perfusing Ileum

• Basic test in gastrointestinal research

• Peristaltic reflex in guinea pig ileum

• For studying emptying phase of peristaltic reflex

This tissue bath has been designed for studying the peristaltic reflex in the guinea-pig ileum. The circular muscle contraction which propels the contents of the ileum from aboral to anal direction is induced by the increase of the intraluminal pressure up to a threshold point. The tissue bath is a water-jacketed Plexiglas bath. The holder for the cannulae can be removed from the main bath during the preparation. A 4 to 5 cm long segment of ileum, where the mesenteric has been removed and which has been flushed is cannulated in the oral and aboral ends and tided. Three different sizes of cannulae are available. The cannulae are fixed on sliding holders to optimize the distance between the cannulae and adapt to the individual length of the ileum avoiding any slackness of the tissue. The inflow is controlled by means of a peristaltic pump with a flowrate of about 0.5 ml/min. The direction of the perfusion flow must meet the physiological way. The outflow can be switched using a stopcock from a level equivalent to the level of the bath to a level of about 3 cm above the level of the fluid in the bath. The peristaltic reflex is induced by changing the position of the outflow stopcock. When it is in position ¡®peristalsis¡¯,  the pressure increases slowly resulting in a distention of the ileum until the pressure threshold level is reached. At this time the emptying phase is started as a visible contraction of the circular muscle moving from the oral to the aboral side.

The intraluminal pressure is recorded from the oral side by a pressure transducer and the appropriated amplifier and recorder. The pressure transducer must be sensitive enough to reproduce the small threshold point of 1 to 2 cmH2O