Effect of feeding on myoelectric activity of the sphincter of Oddi and the gastrointestinal tract in the opossum.

The effect of different foods on the myoelectric activity of the sphincter of Oddi and gastrointestinal tract was evaluated in the opossum. Gallbladder pressure was also recorded. Feeding fat and mixed food resulted in the greatest incidence of spike activity in the duodenum and jejunum, followed by protein. The lowest incidence of slow waves with spikes in the duodenum and jejunum followed feeding of carbohydrates (P less than 0.01). Likewise, the lowest spike activity in the sphincter of Oddi was observed after carbohydrate feeding (P less than 0.05). There was no significant difference in the incidence of spike potentials in the sphincter of Oddi when fat, protein, or mixed food was fed. No significant change in gallbladder pressure during fasting and following feeding of different aliments was observed. We concluded that there is a correlation between the frequency of spike potentials in the sphincter of Oddi and in the small bowel following feeding. The duration of the fed pattern for each type of food correlated with the number of spikes in the sphincter of Oddi and gastrointestinal tract.