title: Mas-related gene (Mrg) C receptors inhibit mechanical allodynia and spinal microglia activation in the early phase of neuropathic pain in rats.
abstract: Mas-related gene (Mrg) C receptors are exclusively expressed in the trigeminal and dorsal root ganglia (DRG). However, their functional roles are poorly understood. This study was aimed to determine the effect of MrgC receptors on pain hypersensitivity in the early phase of neuropathic pain and its underlying mechanisms. Intrathecal (i.t.) administration of the selective MrgC receptor agonist bovine adrenal medulla 8-22 (BAM8-22) at 1 or 10nmol attenuated mechanical allodynia one day after L5 spinal nerve ligation (SNL) surgery. I.t. BAM8-22 (10 nmol) inhibited SNL-induced microglia activation in the spinal dorsal horn on day 2 post-SNL. The BAM8-22 treatment also abolished SNL-induced upregulation of neuronal nitric oxide synthesis (nNOS) in the dorsal root ganglia (DRG). On the other hand, SNL, but not sham, surgery reduced the expression of MrgC receptor mRNA in the injured L5 DRG without changing thier levels in the adjacent uninjured L4 or L6 DRG on day 2 following the surgery. These results suggest that the activation of MrgC receptors can relieve pain hypersensitivity by the inhibition of nNOS increase in DRG neurons and microglia activation in the spinal dorsal horn in the early time following peripheral nerve injury. This study provides evidence that MrgC receptors could be targeted as a novel therapy for neuropathic pain with limited unwanted effects.
authors.affiliation: College of Life Sciences and Provincial Key Laboratory of Developmental Biology and Neuroscience, Fujian Normal University Fuzhou, Fujian 350108, People's Republic of China.
authors.forename: Dongmei
authors.initials: D
authors.lastname: Wang
authors.affiliation: College of Life Sciences and Provincial Key Laboratory of Developmental Biology and Neuroscience, Fujian Normal University Fuzhou, Fujian 350108, People's Republic of China.
authors.forename: Yaping
authors.initials: Y
authors.lastname: Xue
authors.affiliation: College of Life Sciences and Provincial Key Laboratory of Developmental Biology and Neuroscience, Fujian Normal University Fuzhou, Fujian 350108, People's Republic of China.
authors.forename: Yajuan
authors.initials: Y
authors.lastname: Chen
authors.affiliation: College of Life Sciences and Provincial Key Laboratory of Developmental Biology and Neuroscience, Fujian Normal University Fuzhou, Fujian 350108, People's Republic of China.
authors.forename: Liqin
authors.initials: L
authors.lastname: Ruan
authors.affiliation: College of Life Sciences and Provincial Key Laboratory of Developmental Biology and Neuroscience, Fujian Normal University Fuzhou, Fujian 350108, People's Republic of China. Electronic address: yhong@fjnu.edu.cn.
authors.forename: Yanguo
authors.initials: Y
authors.lastname: Hong
mesh_terms: D000818:Animals; D006930:Hyperalgesia / Q000378:metabolism / Q000503:physiopathology*; D008297:Male; D017628:Microglia / Q000187:drug effects / Q000378:metabolism*; D009437:Neuralgia / Q000378:metabolism / Q000503:physiopathology*; D052248:Nitric Oxide Synthase Type I / Q000378:metabolism; D010446:Peptide Fragments / Q000494:pharmacology; D010812:Physical Stimulation; D012333:RNA, Messenger / Q000378:metabolism; D017207:Rats, Sprague-Dawley; D043562:Receptors, G-Protein-Coupled / Q000819:agonists / Q000235:genetics / Q000378:metabolism*; D066148:Spinal Cord Dorsal Horn / Q000187:drug effects / Q000378:metabolism*; D013127:Spinal Nerves / Q000293:injuries; D014110:Touch
chemical_list: C000591603:Mrgprc protein, rat; D010446:Peptide Fragments; D012333:RNA, Messenger; D043562:Receptors, G-Protein-Coupled; C571042:bovine adrenal medulla 8-22; D052248:Nitric Oxide Synthase Type I
keywords: Dorsal root ganglion (DRG); Mas-related gene (Mrg) receptor; Microglia; Neuropathic pain; Spinal dorsal horn