Early myoelectrical activity changes during gastric or duodenal ulceration in dogs.

Antroduodenal myoelectric activity and gastric transmural potential difference were recorded before and during fundic, antral, or duodenal ulceration in dogs. Gastric injury was obtained by electrocoagulation of the fundic or antral mucosa. Duodenal ulceration was induced by cysteamine injection which was accompanied by nausea or vomiting. Both antral electrocoagulation and cysteamine injection were also accompanied by antral dysrhythmia and a transient decrease of the gastric transmural potential difference. Effects of antral electrocoagulation were prevented by selective vagotomy. Since antral dysrhythmia disappeared as soon as the antral or duodenal ulcers became active, ie, within three days and 24 hr respectively, it is suggested that antral dysrhythmia is the result of antroduodenal stimulation and could thus not be assessed as a criterion of active ulceration.