The effect of increased intracolonic pressure on net water, sodium, and unidirectional sodium movement in the ascending colon of adult rats was measured. With elevations of intraluminal pressure from control values of 4 to 30 mm saline, a rapid reversal of net absorption to net secretion occurred; this increased over the next hour, although the pressure was kept stable. Increases in the exsorption or blood-to-lumen movement of sodium were the main reasons for the net secretion observed; it is suggested that an increased intraluminal pressure is transmitted across the mucosa, causing an increase in mucosal interstitial pressure with a diffusion of isotonic saline into the lumen in response to this gradient.
Bury KD, McClure RL, Wright HK. Reversal of Colonic Net Absorption to Net SecretionWith Increased Intraluminal Pressure. Arch Surg. 1974;108(6):854-857. doi:10.1001/archsurg.1974.01350300086020