VAGAL SYSTEM INVOLVEMENT IN CHANGES IN SMALL-BOWEL MOTILITY DURING RESTRAINT STRESS - AN EXPERIMENTAL-STUDY IN THE DOG

Changes in small intestinal motility were studied during restraint str ess in fasting animals and after food; the involvement of the vagal sy stem in the pathophysiology of these changes was assessed. Small intes tinal motility was recorded in 40 dogs using electromyography with mon opolar electrodes and manometry with submucosal microballoons. Twenty animals underwent bilateral truncal vagotomy. Stress increased intesti nal motility (percentage of slow waves followed by action potentials i n 1 min), both in fasting conditions (P < 0.001) and post-prandially ( P < 0.001). It also completely abolished the migrating motor complex-i nterdigestive myoelectric complex periodicity characteristic of the no rmal fasting pattern. In dogs subjected to vagotomy, restraint stress increased motility during fasting (P < 0.001) but decreased it after f eeding (P < 0.01). Restraint stress thus increases small intestinal mo tility, both during fasting and after food. The vagal system is partia lly involved in this hypermotility response.