Duodenal bulb control of the flow rate of digesta in the fasted and fed dog.

Abstract

SUMMARY1. Continuous measurement of the flow of digesta near the pylorus, and 5 cm aborally, was assessed in the conscious dog using a chronically implanted flowmeter. The patterns of flow were related to motor activity of the gastroduodenal junction.2. Electromagnetic measurement of the flow was calibrated in vitro by means of a pulsatile pump. Validation was obtained in vivo by direct evaluation of the amount of chyme collected from an open duodenal cannula and indirectly by a dye-dilution technique.3. After a 12 h fast, only small amounts of gastric contents were delivered into the duodenum. This transfer occurred during periods of irregular motor activity recorded along the gastroduodenal junction, which occupied less than 25% of the recording time. The patterns of flow near the pylorus and beyond the duodenal bulb were correlated to antral and duodenal contractions respectively. 4. After a meal, gastric emptying occurred intermittently and was related to enhanced antral motor activity beyond the duodenal bulb; digesta flowed in clusters of gushes which were related to the duodenal contractions.5. It is concluded that the mechanical role of the duodenal bulb is to change the intermittent juxtapyloric flow of digesta into a uniform flow at the duodenal level.

Patterns of Small Intestinal Motor Activity During Intraluminal Infusion of Elementary Diets in Dogs

“…The observation is not surprising; the duodenum represents a highly specialized segment of the gastrointestinal tract, playing several important regulatory mechanisms, such as gastric emptying [22] and delivery of nutrients to the remaining small intestine [23].…”

Quantification of distal antral contractile motility in healthy human stomach with magnetic resonance imaging

“…This contrasts with the initial conclusions of animal studies, in which an electromagnetic flowmeter was used to measure volumes of gastric outflow. After intragastric infusion of saline, events of outflow usually coincided with antral contractions (1, 8, 45). This has often been taken as an association between phasic motility of the distal stomach and gastric emptying, as well as an explanation of the pulsatile nature of gastric outflow.…”

“…This has often been taken as an association between phasic motility of the distal stomach and gastric emptying, as well as an explanation of the pulsatile nature of gastric outflow. However, outflow and antral contractions were not necessarily initiated together (8, 46), although antral contractions augmented the volume of each saline pulse (8, 45–47). In humans, most US studies consistently provide results indicative of varied association between antral contractions and transpyloric flow.…”

Load-dependent effects of duodenal lipid on antropyloroduodenal motility, plasma CCK and PYY, and energy intake in healthy men

“…As the load of 1.5 kcal/min is considered similar to average gastric emptying, the data may also suggest that if the duration of infusion was longer, plasma PYY may have continued to rise (to a specific threshold) to have an effect on energy intake. It is important to recognize that unlike duodenal infusions, gastric emptying of fat is not a steady process but rather is usually more rapid early after a meal, slowing later, and presumably predominantly pulsatile rather than continuous (32), a pattern that is likely to result in a different distribution of free fatty acids along the gut.…”