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Neuropeptide Y stimulates bile secretion via Y1 receptor in the left dorsal vagal complex in rats
Author(s) -
Yoneda Masashi,
Nakamura Kimihide,
Yokohama Shiro,
Tamori Keisuke,
Sato Yoichi,
Aso Kazunobu,
Aoshima Masaru,
Kono Toru,
Makino Isao
Publication year - 1998
Publication title -
hepatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.488
H-Index - 361
eISSN - 1527-3350
pISSN - 0270-9139
DOI - 10.1002/hep.510280311
Subject(s) - endocrinology , medicine , peptide yy , neuropeptide y receptor , pancreatic polypeptide , microinjection , vagotomy , biology , receptor , stimulation , gastric acid , secretion , neuropeptide , chemistry , insulin , glucagon
Neuropeptide Y (NPY) injected into the cerebrospinal fluid and the left dorsal vagal complex enhances bile acid–independent and bicarbonate‐dependent bile secretion through vagal muscarinic pathways in animal models. NPY binds to and activates six different receptor subtypes, and NPY Y1 and Y2 receptors are distributed in the dorsal vagal complex. We sought to determine which NPY receptor subtypes are involved in central stimulation of bile secretion by examining the effect of microinjection of specific NPY receptor agonists into the dorsal vagal complex. The bile duct was cannulated in urethane‐anesthetized and bile acid–compensated rats. After measuring basal secretion, NPY, peptide YY (PYY), [Leu 31 , Pro 34 ]NPY, NPY(13‐36), or NPY(3‐36) was microinjected into the either right or left dorsal vagal complex and bile secretion was observed for 100 minutes. Hepatic branch vagotomy was performed 2 hours before the peptide injection. Microinjection of NPY and PYY (8 pmol) into the left dorsal vagal complex increased bile secretion. [Leu 31 , Pro 34 ]NPY microinjected into the left dorsal vagal complex also dose‐dependently (1‐8 pmol) stimulated bile acid–independent and bicarbonate‐dependent bile secretion. Microinjection of NPY(13‐36) into the left dorsal vagal complex did not stimulate and NPY(3‐36) dose‐dependently inhibited bile secretion. Stimulation of bile secretion by [Leu 31 , Pro 34 ]NPY was abolished by hepatic branch vagotomy. NPY acts in the left dorsal vagal complex to stimulate bile acid–independent and bicarbonate‐dependent bile secretion via Y1 receptor subtype.