Inhibitory effect of luminal saccharides on glucose absorption from an adjacent jejunal site in rats: a newly described intestinal neural reflex

Nutrients in the lumen of the small intestine are sensed by special cells in the epithelial lining. The ensuing neurohumoral reflexes affect gastrointestinal absorption/secretion, motility, and vascular perfusion. To study in vivo the effect of a monosaccharide (glucose) or polysaccharide (starch) present in the jejunum on glucose absorption from an adjacent part of the intestine and investigate the possible underlying mechanisms. Using the single pass intraluminal perfusion technique, a segment of jejunum (perfusion segment) was continuously perfused with 20 mM glucose to determine glucose absorption. One hour later, a bolus of a saccharide was instilled in an isolated adjacent jejunal segment and the change in glucose absorption was monitored for a further 2 h. The contribution of neural mechanisms in this process was investigated. Instillation of glucose (20 mM or 40 mM) in either distal or proximal jejunal pouch elicited immediate and sustained inhibition of glucose absorption (a decrease by 25%; P