Guinea Pig Ileum DEMO

Methods (i)


Preparation

In this experiment you are provided with a short length of guinea pig ileum set up such that contractions of the intestine, either due to the addition of selected drugs to the gut-bath or to transmural electrical stimulation, may be recorded. Since the guinea pig ileum shows little spontaneous activity a steady baseline may be achieved making this a suitable preparation for investigating dose-response relationships or the action of certain drugs and their antagonists on contraction.

In addition electrical (transmural) stimulation of the gut causes release of neurotransmitters from the enteric nervous system. Stimulation at low frequencies (0.1 Hz) causes the release of acetylcholine resulting in contraction of the ileum. Stimulation at high frequencies (10 Hz) elicits the release of substances which modify intestinal motility.

In isolated tissue segments the smooth muscle cells will respond to stimuli for many hours provided certain conditions are fulfilled. The tissue should be suspended in a physiological solution such as Tyrode's solution, at a suitable temperature (37°C) and provided with oxygen (the solution should be aerated with oxygen or compressed air).