title: Effect of motilin on the discharge of rat hippocampal neurons responding to gastric distension and its potential mechanism.
abstract: The study aims to find the effect of motilin on neuronal activity of gastric distension-responsive neurons in rat hippocampus and its possible mechanism. Single unit discharges in the hippocampal CA1 region were recorded extracellularly by means of four-barrel glass micropipettes in anesthetized rats and the expression of nNOS in hippocampus was observed by fluo-immunohistochemistry staining. Of the 171 recorded neurons, 76.0% were GD-excitatory (GD-E) neurons and 24.0% were GD-inhibited (GD-I) neurons. The 57.6% of GD-E neurons showed an excitatory response to motilin and the same effect was observed in 51.7% GD-I neurons. However, when NOS inhibitor nitro-l-arginine methyl ester (l-NAME) was administrated previously, the followed motilin-induced excitatory responsiveness of GD-responsive neurons was reduced. In contrast, discharge activity of GD-responsive neurons with motilin was enhanced by pretreatment of NO precursor l-arginine. The expression of nNOS-IR positive neurons was significantly increased in CA1 after administration of motilin. Our findings suggested that motilin excited the GD-responsive neurons in the hippocampal CA1 region and the excitatory effect of motilin may be mediated by the endogenous NO.
authors.affiliation: Department of Pathophysiology, Medical College of Qingdao University, 38# Dengzhou Road, Qingdao, Shandong 266021, PR China. xu.luo@163.com
authors.forename: Luo
authors.initials: L
authors.lastname: Xu
authors.forename: Xiangrong
authors.initials: X
authors.lastname: Sun
authors.forename: Inge
authors.initials: I
authors.lastname: Depoortere
authors.forename: Jiang
authors.initials: J
authors.lastname: Lu
authors.forename: Feifei
authors.initials: F
authors.lastname: Guo
authors.forename: Theo Louis
authors.initials: TL
authors.lastname: Peeters
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D013271:Gastric Dilatation / Q000209:etiology; D005765:Gastrointestinal Agents / Q000008:administration & dosage / Q000494:pharmacology*; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D008297:Male; D009037:Motilin / Q000008:administration & dosage / Q000494:pharmacology*; D019331:NG-Nitroarginine Methyl Ester / Q000008:administration & dosage / Q000494:pharmacology; D009474:Neurons / Q000378:metabolism / Q000502:physiology*; D009569:Nitric Oxide / Q000378:metabolism; D052248:Nitric Oxide Synthase Type I / Q000037:antagonists & inhibitors / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
chemical_list: D005765:Gastrointestinal Agents; D009569:Nitric Oxide; D009037:Motilin; D052248:Nitric Oxide Synthase Type I; D019331:NG-Nitroarginine Methyl Ester