DIVERGENT EFFECT OF SALINE AND GLUCOSE SOLUTIONS ON MYOELECTRIC AND MOTOR-ACTIVITY OF CANINE SMALL-BOWEL

Previous work has shown that stimulation of osmotic receptors in the d uodenal mucosa is followed by an increase in small intestinal motility . This effect was consistently observed with saline solutions, while s timulation or inhibition is observed when glucose is the solute. To ga in further insight into the mechanisms of these apparent contradictory effects, we have perfused the intestine with saline and glucose solut ions while simultaneously recording small bowel electrical and motor a ctivity. Also to elucidate the influence of the spontaneous fasting ac tivity, infusions were done on two different phases of the migrating m otor complex infusion of 10 ml of both NaCl and glucose (1250 and 2500 mOsm/kg) in Phase I of the migrating motor complex, elicited the appe arance of spike potentials and contractions. When infused during Phase II, NaCl caused an increase in the frequency of the irregular motor a ctivity characteristics of this phase, due to a greater coupling of el ectrical and motor events. Also a greater amplitude of contractions wa s seen. In contrast, glucose infusion in Phase II was associated with a decrease of both electrical events and contractions. We conclude tha t the effect of hyperosmolar solutions is influenced by the solute and the phase of the migrating motor complex in which they are infused.