DISTRIBUTION OF ENTERIC NEURAL PEPTIDE YY IN THE DOG GASTROINTESTINAL-TRACT

Various regions of the dog gastrointestinal tract were investigated fo r the distribution of peptide YY (PYY) neurons using immunocytochemist ry and radioimmunoassay. PYY neurons that encircled non-PYY-immunoreac tive neurons were mainly observed in the myenteric plexus from the sto mach to the colon. There was more PYY-like immunoreactivity in the mus cle layer of the stomach and ileum than in the other intestines. The r esults of high performance liquid chromatography revealed that neural PYY-immunoreactive substance is identical to authentic PYY. PYY was no t localized in the cholinergic neurons. These results indicate that PY Y, as a neuropeptide, is involved in the regulation of gastrointestina l function.