The relationship between cardiovascular changes and intestinal absorption of salts and water in the canine ileum following hemorrhage

Experiments were undertaken to measure the regional blood flow and blood pressure in the canine ileum, and to determine the unidirectional fluxes of sodium and water, and net flux of 3-O-[raised 14]CHlowered 3]-glucose. An eight-inch segment of terminal Ileum was Isolated with Its nerve and blood supply intact. The gut was filled with an isosmotlc solution of NaCl and MgSO[lowered 4], containing [raised 22]Na, [raised 3]H[lowered 2]O, 3-O-[raised 14]CH[lowered 3]-glucose, and phenol red as a poorly absorbed volume indicator. A branch of the mesenteric vein draining the segment was cannulated with a Jelco IV catheter. Normally the blood was allowed to flow back into the femoral vein. Blood flow was estimated by collecting blood into a graduate for one minute. Transmural potentials were determined with a high impedance electrometer. Samples were taken at fifteen minute intervals through gut cannulae. Tracer activity was measured by liquid scintillation counting. Unidirectional fluxes were calculated by the method of Berger and Steele. The animals were hemorrhaged 20% of the estimated blood volume. Following removal of the blood there was a significant decrease (P<0.01) in blood flow and blood pressure. There was a significant increase (P<0.05) in sodium absorbed. The increase was due to a significant decrease in flux into the lumen, and not flux out of the lumen. There was a significant decrease in water influx and efflux, but no change in the volume absorbed.