title: Pancreatic polypeptide and peptide YY3-36 induce Ca2+ signaling in nodose ganglion neurons.
abstract: Peripheral injection of pancreatic polypeptide (PP) and peptide YY(3-36) (PYY(3-36)), the hormones released in response to meals, reduce food intake, in which the rank order of the potency is PP>PYY(3-36). These anorectic effects are abolished in abdominal vagotomized rats, suggesting that PP and PYY(3-36) induce anorexia via vagal afferent nerves. However, it is not clear whether PP and PYY(3-36) directly act on vagal afferent neurons. In this study, we examined the effects of PP and PYY(3-36) on cytosolic Ca(2+) concentration ([Ca(2+)](i)) in isolated nodose ganglion neurons of the mouse vagal afferent nerves. At 10(-11)M, PP but not PYY(3-36) recruited a significant population of nodose ganglion neurons into [Ca(2+)](i) increases. PP at 10(-11) to 10(-7) and PYY(3-36) at 10(-10) to 10(-7)M increased [Ca(2+)](i) in a concentration-dependent manner. At submaximal to maximal concentrations of 10(-10) and 10(-8)M, PP increased [Ca(2+)](i) in approximately twice greater population of nodose ganglion neurons than PYY(3-36). Furthermore, the majority of PP-responsive neurons also exhibited [Ca(2+)](i) responses to cholecystokinin-8, a hormone known to induce satiety through activating nodose ganglion neurons. The results demonstrate that PP and PYY(3-36) directly activate nodose ganglion neurons and suggest that the marked effect of PP on cholecystokinin-8-responsive nodose ganglion neurons could be linked to the regulation of feeding.
authors.affiliation: Division of Integrative Physiology, Department of Physiology, Jichi Medical University School of Medicine, Shimotsuke, Tochigi 320-0498, Japan.
authors.forename: Yusaku
authors.initials: Y
authors.lastname: Iwasaki
authors.forename: Masafumi
authors.initials: M
authors.lastname: Kakei
authors.forename: Hajime
authors.initials: H
authors.lastname: Nakabayashi
authors.forename: Enkh-Amar
authors.initials: EA
authors.lastname: Ayush
authors.forename: Misato
authors.initials: M
authors.lastname: Hirano-Kodaira
authors.forename: Yuko
authors.initials: Y
authors.lastname: Maejima
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Yada
mesh_terms: D000818:Animals; D020013:Calcium Signaling / Q000187:drug effects*; D002211:Capsaicin / Q000494:pharmacology; D004435:Eating / Q000502:physiology; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D009474:Neurons / Q000187:drug effects*; D009475:Neurons, Afferent / Q000187:drug effects; D009478:Neuropeptide Y / Q000494:pharmacology*; D009620:Nodose Ganglion / Q000166:cytology / Q000187:drug effects*; D010191:Pancreatic Polypeptide / Q000494:pharmacology*; D010446:Peptide Fragments / Q000494:pharmacology*; D019894:Peptide YY / Q000494:pharmacology*; D011189:Potassium Chloride / Q000494:pharmacology; D051381:Rats; D012844:Sincalide / Q000378:metabolism; D014630:Vagus Nerve / Q000166:cytology / Q000187:drug effects
chemical_list: D009478:Neuropeptide Y; D010446:Peptide Fragments; D019894:Peptide YY; C061785:peptide YY (3-36); D010191:Pancreatic Polypeptide; D011189:Potassium Chloride; D012844:Sincalide; D002211:Capsaicin