INTRACISTERNAL INJECTION OF PEPTIDE YY INHIBITS GASTRIC-EMPTYING IN RATS

Peptide YY (PYY) has been shown to effectively regulate gastrointestin al function when administered intravenously. In the present study, the effect of intracisternal (i.c.) injection of rat PYY on the rate of g astric emptying was investigated in conscious animals. Vehicle, bombes in or different doses of PYY was given i.c. after animals had been giv en an oral liquid meal. A dose-dependent inhibition of gastric emptyin g was observed following the injection of PYY (400 fmol, 40 fmol and 4 0 amol; in 10 mu l) into the cisterna magna. The 400 fmol dose of PYY produced an inhibition of similar magnitude as that caused by bombesin (600 fmol in 10 mu l). Furthermore, subdiaphragmatic vagotomy resulte d in an elimination of the inhibitory PYY effect on gastric emptying, suggesting that PYY action to inhibit gastric function depends on inta ct vagal pathways.