title: Neuropeptide Y hyperpolarizes submucosal neurons of the guinea-pig descending colon.
abstract: Effects of neuropeptide Y (NPY) on submucosal neurons of the guinea-pig descending colon were investigated electrophysiologically by means of intracellular electrophysiological recordings. NPY (100 nM) induced a marked and prolonged hyperpolarization, accompanied by a decrease in input resistance in most (90%) neurons. This NPY-induced hyperpolarization was diminished and augmented by membrane hyperpolarization and depolarization, respectively. The NPY-hyperpolarization was not affected by exposure to either calcium-free solutions or the alpha2-adrenoceptor antagonist, idazoxan (1 microM). When more than one peptide was applied to a neuron, NPY, PYY and Pro34-NPY were equipotent, whilst NPY13-36 was less potent. It was concluded that NPY hyperpolarized submucosal neurons of the guinea-pig descending colon, possibly via a direct action on postsynaptic Y1-receptor and increasing potassium conductance.
authors.affiliation: University of Aberdeen, Department of Biomedical Sciences, Marischal College, UK. hiraauto@mri.tmd.ac.jp
authors.forename: K
authors.initials: K
authors.lastname: Hirai
authors.forename: K N
authors.initials: KN
authors.lastname: Browning
authors.forename: G M
authors.initials: GM
authors.lastname: Lees
mesh_terms: D000818:Animals; D003106:Colon / Q000294:innervation*; D004594:Electrophysiology; D006168:Guinea Pigs; D008297:Male; D008564:Membrane Potentials / Q000502:physiology; D009474:Neurons / Q000187:drug effects* / Q000502:physiology; D009478:Neuropeptide Y / Q000494:pharmacology*; D013368:Submucous Plexus / Q000166:cytology*
chemical_list: D009478:Neuropeptide Y