Small bowel extrinsic denervation does not alter water and electrolyte absorption from the colon in the fasting or early postprandial state.

Small bowel transplantation (SBT) causes watery diarrhea. The decreases shown previously in absorption of water, electrolytes, and bile salts in the jejunum and ileum, although present, are not dramatic and seem not to be great enough to explain the diarrhea. Our aim was to determine changes in water and electrolyte absorption in the colon during fasting and postprandially in a canine preparation of jejunoileal extrinsic denervation, which serves as a model of jejunoileal autotransplantation. We hypothesized that colonic absorption of water and electrolytes decreases transiently in the colon after SBT. Six dogs had cannulas implanted in the colon to study absorption of an ileal-like basal electrolyte solution with or without 10 mmol/L glucose. Absorption during fasting and postprandially was measured before and 2 and 12 weeks after a validated preparation of jejunoileal extrinsic denervation. All dogs developed diarrhea after SBT. Net colonic absorptive fluxes of water and electrolytes in the colon did not change from baseline values at 2 or 12 weeks after extrinsic denervation, either during fasting or postprandially; glucose in the infusate did not alter absorptive fluxes during fasting or postprandially. Extrinsic denervation of the small intestine does not appear to alter colonic absorption of water or electrolytes during fasting or postprandially. These observations suggest that the neurally intact colon has a minimal role in the diarrhea after SBT.