Impact of neodecortication on colon motor response to a meal in the rat

The colon motor response to a meal consisting of 100 mM of sodium oleate was assessed before and after neodecortication in male Sprague-Dawley rats. Recording probes were anchored surgically in the ascending and descending colon. Pressure changes were recorded on a dynograph using a low-compliance perfusion system. A motility index took into account the amplitude, duration, and frequency of contractions. Neodecortication increased the motility index of the distal colon in the fasting state. However, removal of the cerebral cortex did not affect significantly the colon motor response to a meal. Meal stimulation increased the motility index before and after neodecortication. These findings suggest that resting colonic motor activity is increased after neodecortication, probably through the loss of an inhibitory influence of the central nervous system; and the cerebral cortex is not required for the colon response to a meal in the rat.