Inhibitory effect of peptide YY on gastric acid output in rats

The administration of peptide YY (PYY: 0.8, 1.6 and 3.2 nmol/kg/h, i.v.) to fasting rats inhibited not only baclofen (2 mg/kg, s.c.)-stimulated gastric acid output and gastric mucosal blood flow, but also pentagastrin (8 micrograms/kg/h, i.v.)-stimulated gastric acid output. PYY (3.2 nmol/kg/h) reduced baclofen-induced acid output more than pentagastrin-induced acid output, i.e., by 61.8 +/- 11.5% compared to 35.3 +/- 8.2%. PYY inhibited acetylcholine (ACh) release from cholinergic nerve endings of gastric body evoked by electrical transmural stimulation (ETS: 1 msec, 10 V, 3 Hz, 30 sec) by 47.2 +/- 3.5%. The mechanism of the inhibitory effect of PYY on gastric acid output seems to involve decreased gastric mucosal blood flow and reduced ACh release from cholinergic nerves.