title: Temporal changes in MrgC expression after spinal nerve injury.
abstract: Mas-related G-protein-coupled receptor subtype C (MrgC) may play an important role in pain sensation. However, the distribution of MrgC receptors in different subpopulations of rodent dorsal root ganglion (DRG) neurons has not been clearly demonstrated owing to a lack of MrgC-selective antibody. It is also unclear whether peripheral nerve injury induces different time-dependent changes in MrgC expression in injured and uninjured DRG neurons. Here we showed that MrgC immunoreactivity is distributed in both IB4-positive (non-peptidergic) and calcitonin gene-related peptide-positive (peptidergic) DRG neurons in mice and rats. Importantly, the MrgC mRNA level and MrgC immunoreactivity were both decreased in the injured L5 DRG compared to corresponding levels in the contralateral (uninjured) DRG in rats on days 14 and 30 after an L5 spinal nerve ligation. In contrast, mRNA and protein levels of MrgC were increased in the adjacent uninjured L4 DRG. Thus, nerve injury may induce temporal changes in MrgC expression that differ between injured and uninjured DRG neurons. In animal behavior tests, chronic constriction injury of the sciatic nerve induced mechanical pain hypersensitivity in wild-type mice and Mrg-clusterΔ(-/-) mice (Mrg KO). However, the duration of mechanical hypersensitivity was longer in the Mrg KO mice than in their wild-type littermates, indicating that activation of Mrgs may constitute an endogenous mechanism that inhibits the maintenance of neuropathic pain in mice. These findings extend our knowledge about the distribution of MrgC in rodent DRG neurons and the regulation of its expression by nerve injury.
authors.affiliation: Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA.
authors.forename: S-Q
authors.initials: SQ
authors.lastname: He
authors.affiliation: The Solomon H. Snyder Department of Neuroscience, Center for Sensory Biology, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA.
authors.forename: L
authors.initials: L
authors.lastname: Han
authors.affiliation: The Solomon H. Snyder Department of Neuroscience, Center for Sensory Biology, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA.
authors.forename: Z
authors.initials: Z
authors.lastname: Li
authors.affiliation: Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA.
authors.forename: Q
authors.initials: Q
authors.lastname: Xu
authors.affiliation: Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA.
authors.forename: V
authors.initials: V
authors.lastname: Tiwari
authors.affiliation: Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA.
authors.forename: F
authors.initials: F
authors.lastname: Yang
authors.affiliation: Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA.
authors.forename: X
authors.initials: X
authors.lastname: Guan
authors.affiliation: Department of Anesthesiology, Beijing Chaoyang Hospital, Capital Medical University, Beijing 100020, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA.
authors.forename: S N
authors.initials: SN
authors.lastname: Raja
authors.affiliation: The Solomon H. Snyder Department of Neuroscience, Center for Sensory Biology, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA; Howard Hughes Medical Institute, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA. Electronic address: xdong2@jhmi.edu.
authors.forename: X
authors.initials: X
authors.lastname: Dong
authors.affiliation: Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA. Electronic address: yguan1@jhmi.edu.
authors.forename: Y
authors.initials: Y
authors.lastname: Guan
mesh_terms: D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000378:metabolism; D005727:Ganglia, Spinal / Q000378:metabolism*; D006930:Hyperalgesia / Q000209:etiology / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009437:Neuralgia / Q000378:metabolism; D009474:Neurons / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D043562:Receptors, G-Protein-Coupled / Q000235:genetics / Q000378:metabolism*; D020426:Sciatic Neuropathy / Q000150:complications / Q000378:metabolism*; D013127:Spinal Nerves / Q000293:injuries*; D013997:Time Factors; D014110:Touch
chemical_list: C000591604:MrgC protein, mouse; C000591603:Mrgprc protein, rat; D012333:RNA, Messenger; D043562:Receptors, G-Protein-Coupled; D015740:Calcitonin Gene-Related Peptide
keywords: MrgC; dorsal root ganglion; nerve injury; neuropathic pain