title: Orexin-A affects gastric distention sensitive neurons in the hippocampus and gastric motility and regulation by the perifornical area in rats.
abstract: Orexin-A is mainly produced in the lateral hypothalamus (LHA) and the perifornical area (PeF). Here, we aim to elucidate the effects of orexin-A in the hippocampus (Hi) on gastric distention (GD)-sensitive neurons and gastric motility, and potential regulation mechanisms by the PeF. Retrograde tracing and fluorescent-immunohistochemical staining were used to determine orexin-A neuronal projections. Single unit discharges in the Hi were recorded extracellularly and gastric motility in conscious rats was monitored during administration of orexin-A to the Hi or electrical stimulation of the PeF. Orexin-A administration to the Hi excited most of the GD-excitatory (GD-E) neurons and GD-inhibitory (GD-I) neurons, and increased gastric motility in a dose-dependent manner. All of effects induced by orexin-A could be partly blocked by pretreatment with orexin-A antagonist, SB-334867. Electrical stimulation of the PeF excited the majority of the orexin-A-responsive GD neurons in the Hi and promoted gastric motility. Additionally, pretreatment with SB-334867 in the Hi increased the firing rate of GDI and GDE neurons following electrical stimulation of the PeF. These findings suggest that orexin-A could regulate activities of GD-sensitive neurons and gastric motility. Furthermore, the PeF may be involved in this regulatory pathway.
authors.affiliation: Department of Pathophysiology, Medical College of Qingdao University, Qingdao 266021, China.
authors.forename: Shu
authors.initials: S
authors.lastname: Sun
authors.affiliation: Department of Pathophysiology, Medical College of Qingdao University, Qingdao 266021, China. Electronic address: xu.luo@163.com.
authors.forename: Luo
authors.initials: L
authors.lastname: Xu
authors.affiliation: Department of Pathophysiology, Medical College of Qingdao University, Qingdao 266021, China.
authors.forename: Xiangrong
authors.initials: X
authors.lastname: Sun
authors.affiliation: Department of Pathophysiology, Medical College of Qingdao University, Qingdao 266021, China.
authors.forename: Feifei
authors.initials: F
authors.lastname: Guo
authors.affiliation: Department of Pharmacy, College of Chemical Engineering, Qingdao University of Science and Technology, Qingdao, China.
authors.forename: Yanling
authors.initials: Y
authors.lastname: Gong
authors.affiliation: Department of Pathophysiology, Medical College of Qingdao University, Qingdao 266021, China.
authors.forename: Shengli
authors.initials: S
authors.lastname: Gao
mesh_terms: D000818:Animals; D004558:Electric Stimulation; D013271:Gastric Dilatation / Q000503:physiopathology*; D005769:Gastrointestinal Motility; D006624:Hippocampus / Q000503:physiopathology*; D007026:Hypothalamic Area, Lateral / Q000502:physiology*; D008297:Male; D009474:Neurons / Q000502:physiology*; D000068797:Orexins / Q000494:pharmacology / Q000502:physiology*; D017208:Rats, Wistar; D013270:Stomach / Q000294:innervation / Q000503:physiopathology
chemical_list: D000068797:Orexins
keywords: Electrophysiological experiment; Gastric distension responsive neurons; Gastric motility; Hippocampus; Orexin-A; The perifornical area