PHYSIOLOGIC SIGNIFICANCE OF INTRALUMINAL PRESSURE CHANGES IN RELATION TO PROPULSION AND ABSORPTION IN HUMAN JEJUNUM

For a study of the effect of motility on the propulsion and absorption of the luminal contents in a 25-cm. segment of human jejunum, a method was devised that allowed simultaneous recording of intraluminal pressure changes, determination of transit time by indicator-dilution technics, and assessment of the absorption of glucose and xylose under basal conditions. The motility of the segment of jejunum under study influenced the speed of propulsion of the intraluminal contents. The motility and the transit time were not influenced by the presence of a constant infusion of an isotonic solution at 37° C and a rate of 10 ml./min. Increased motility per minute resulted in shorter transit times. More physiologically significant than the quantitative values were the patterns of motility. The caudad propagation of waves and the extent of the propagation-regardless of wave type-produced shortening of the transit time. The shortest transit times were obtained in experiments during which caudad propagation of motility involved the entire segment under study. Glucose was almost completely absorbed by the time it reached the sampling point. A significant correlation was observed between the values of xylose absorption and transit time, suggesting that longer exposure to the intestinal mucosa increases xylose absorption. © 1968 Hoeber Medical Division • Harper & Row, Publishers, Incorporated.