Canine gastric pacemaker.

KELLY, KEITH A., AND CHARLES F. CODE. Canine gastric pacemaker. Am. J. Physiol. 220( 1) : 112-l 18. 1971 .-Our objective was to determine the site of origin of the canine gastric pacesetter potential (PP). In six dogs, longitudinal (orad-to-caudad) gastric bisection was performed, the greater (GC) and lesser curvature (LC) halves were reunited, and electrodes were implanted on each half. After recovery, gastric electric activity was recorded intermittently in the conscious fasted dogs for 3 months. The orad one-fourth of the stomach along the GC was then resected, and the dogs were restudied. After bisection, the PP of the GC arose in the orad corpus, had a regular rhythm and a mean frequency of 5.2 cycles/min, and was propagated caudally. In contrast, the PP of the LC at first arose from multiple sites and had an irregular rhythm and a slower mean frequency of 3.2 cycles/min. However, the frequency of the PP of the LC gradually increased and, by 14 days after bisection, the PP of the LC was coupled to that of the GC. Resection of the orad corpus along the GC decreased the PP frequency in the remaining stomach about 1 cycle/min, but did not alter electric coupling between the halves or PP propagation. The data indicate that the dominant site of origin of the gastric PP is in the GC half of the orad corpus.