Effect of region, temperature and neuronal blockade on sodium and 51Cr-EDTA transport across canine gastrointestinal mucosae in vitro

Muscle-stripped segments of canine stomach, ileum and colon have been used to identify regional differences in the movement of sodium and 51Cr-EDTA, and the effect that temperature has on the flux of these probes. Flux measurements revealed that the rate of movement of both probes followed the pattern ileum > colon > stomach. Analysis of flux ratios at 25 degrees C and 37 degrees C revealed that sodium moves actively and 51Cr-EDTA moves passively across gastrointestinal epithelia. Blockade of tonic neuronal activity did not affect the in vitro movement of either probe across the ileum.