Propulsive Gut Motility in Mice or Rats

To study the side effect potential of a candidate compound on gastrointestinal motility the passage of a charcoal meal through the gastrointestinal tract in mice or rats is a simple, reliable and widely used method of safety pharmacologists. 

Groups of 10 mice weighing 15 g are fed an oat diet for 3 days. Eighteen hours prior to the experiment food, but not water, is withdrawn. The animals are treated either subcutaneously 15 min or orally 60 min before administration of the charcoal meal (0.2 ml of a 4 % suspension of charcoal in 2 % carboxymethylcellulose solution). The mice are sacrificed after various time intervals, 20 min, 40 min, 60 min and 120 min. Ten animals serve as controls for each time interval. The entire intestine is immediately removed and immersed in 5% formalin to halt peristalsis then washed in running water. The distance the meal has travelled through the intestine as indicated by the charcoal is measured and expressed as percent of the total distance from the pylorus to the caecum. 

The values for the treated groups with the candidate compound for each time point are compared to those for the vehicle control group by using appropriate statistical methods. By using several doses of the candidate compound a dose-response curve can be established. 

The charcoal passage test can be used for evaluation of laxative activity as well as for inhibition of intestinal motility. 

Instead of charcoal, unsubstituted Hostapermblau (CuPcB) suspended in gummi arabicum mucilage can be used. 

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Transit time Propulsive gut motility in mice or rats (charcoal)... 

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