Abstract
The effects of chemical and mechanical stimulations on gastric motility was studied in 19 anesthetized dogs by using electro-myographical techniques. The animals were fasted for 18hr or more before each experiment. Six or eight bipolar silver-wire electrodes were implanted on a gastric wall serially from the fundus to the terminal antrum. At the pre-stimulation stage, the periodic simple electrical activity, which is called electrical control activity (ECA), was regularly recorded from the corpus to the antrum of the stomach; the frequency of which was 4.5±0.5cycles/min on the average. Mechanical stimulation (distention of the stomach) decreased the ECA frequency depending on the degree of distention. The ECA frequency was decreased to 2.9±0.4 cycles/min by the 400ml distention. Chemical stimulations to the gastric antral mucosa also decreased the ECA frequency depending on the strength of acidity or alkalinity. The instillation of a solution of pH 1 or 12.5 into the stomach decreased the ECA frequency to 3.4±0.7, and 3.5±0.5cycles/min, respectively. A stronger alkaline solution induced anti-peristaltic discharges in 4 of 6 cases. The results indicate that both mechanical and chemical stimulations decrease the ECA frequency depending on stimulus strength.
