EFFECT OF PEPTIDE YY ON GASTRIC MOTOR AND SECRETORY ACTIVITY IN VAGALLY INNERVATED AND DENERVATED CORPUS POUCH DOGS

In this study, we examined the mechanism by which constant intravenous infusion of physiological doses of PYY affects gastric secretion and motility in the vagally innervated (Pavlov) and denervated (Heidenhain ) corpus pouch. As a result, only in the Heidenhain pouch, PYY at a do se of 100 pmol/kg-h significantly inhibited gastric secretion in the i nterdigestive and postprandial states, A dose of 300 pmol/kg-h inhibit ed the gastric secretion in both types of pouch, but inhibition in the Pavlov pouch was less than in the Heidenhain pouch. The inhibitory ef fect of PYY on phase III contractile activity was dose-dependent and s ignificant, except in the Heidenhain pouch, and no dose of PYY had any effect on postprandial gastric motility. After all, vagal denervation enhanced the inhibitory effect of PYY on gastric secretion, but aboli shed the inhibitory effect on phase III contractile activity. Our find ings strongly suggest that the inhibitory effect of PYY on gastric sec retion is in part mediated by a non-vagal pathway and the inhibitory e ffect of PYY on gastric motor activities is completely dependent on va gal innervation, but the vagus nerve acts as an inhibitory modulator o f the inhibitory effect of PYY on gastric secretion.