Incoordination of gastroduodenal myoelectric activity in rabbits under immobilization stress was manifested, first, in an earlier resumption of spike activity in the duodenum than in the stomach and pyloric sphincter after its simultaneous suppression in these three pasts of the gastrointestinal tract and, second, in the subsequent considerable increase of duodenal spike activity over its baseline level, while stomach and pyloric sphincter activities remained reduced. The incoordination of gastroduodenal myoelectric activity, which developed during the frost hour of immobilization, was accompanied by the formation of erosive lesions in the gastric mucosa. The results of this study suggest that incoordination of gastroduodenal motor activity may be implicated in stressinduced gastric ulcers as a factor that damages the gastric rfiucosa by slowing down the evacuation of stomach contents and promoting duodenogastric reflux. Key Words: gastroduodenal myoelectric activity; immobilization stress; gastric ulcer formationWe have shown previously that stress associated with arterial blood loss impairs the coordination of gastroduodenal myoelectric activity (GMA) by stepping up activity of the duodenum and weakening that of the stomach [7]. Gastroduodenal incoordination of this type also occurs in rabbits administered ulcerogenic doses of serotonin [6] or pentagastrin [8]. The existence of a correlation between gastric mucosal lesions and incoordination of gastric and duodenal activity suggests a pathogenic role of gastroduodenal incoordination in gastric ulcer formation. Hence the interest in the study of GMA under stress. One of the stressors that lead to gastric ulcer formation in animals is their immobilization [3,13,14]. The aim of this study was to measure GMA in rabbits under immobilization stress.