SPONTANEOUS MOTILITY OF THE PYLORIC SPHINCTER AND ADJACENT REGIONS OF THE GUT IN THE UNANESTHETIZED DOG

Abstract

The balloon method was employed in unanesthetized dogs to record the tone and motility variations simultaneously in the pyloric antrum. sphincter and duodenal bulb. In the fasting state and also during gastric evacuation frequent peristaltic waves passed over these structures. The sequential relations demonstrated that the sphincter and bulb are relaxed during the antral contraction, thus favoring gastric evacuation. Contraction of the sphincter usually preceded and lasted throughout bulbar contraction and thus interfered with regurgitation into the antrum, which was relaxed during this interval. A unity of response (tendency to behave as a unit) in these portions of the gut was emphasized in respect to the passage of peristaltic waves, tone changes and the effect of a variety of stimuli from the stomach or duodenum. The fundamental motility was not essentially modified by bilateral vagotomy.