title: The inhibition of high-voltage-activated calcium current by activation of MrgC11 involves phospholipase C-dependent mechanisms.
abstract: High-voltage-activated (HVA) calcium channels play an important role in synaptic transmission. Activation of Mas-related G-protein-coupled receptor subtype C (MrgC; mouse MrgC11, rat homolog rMrgC) inhibits HVA calcium current (ICa) in small-diameter dorsal root ganglion (DRG) neurons, but the intracellular signaling cascade underlying MrgC agonist-induced inhibition of HVA ICa in native DRG neurons remains unclear. To address this question, we conducted patch-clamp recordings in MrgA3-eGFP-wild-type mice, in which most MrgA3-eGFP(+) DRG neurons co-express MrgC11 and can be identified for recording. We found that the inhibition of HVA ICa by JHU58 (0.001-100nM, a dipeptide, MrgC-selective agonist) was significantly reduced by pretreatment with a phospholipase C (PLC) inhibitor (U73122, 1μM), but not by its inactive analog (U73343) or vehicle. Further, in rats that had undergone spinal nerve injury, pretreatment with intrathecal U73122 nearly abolished the inhibition of mechanical hypersensitivity by intrathecal JHU58. The inhibition of HVA ICa in MrgA3-eGFP(+) neurons by JHU58 (100nM) was partially reduced by pretreatment with a Gβγ blocker (gallein, 100μM). However, applying a depolarizing prepulse and blocking the Gαi and Gαs pathways with pertussis toxin (PTX) (0.5μg/mL) and cholera toxin (CTX) (0.5μg/mL), respectively, had no effect. These findings suggest that activation of MrgC11 may inhibit HVA ICa in mouse DRG neurons through a voltage-independent mechanism that involves activation of the PLC, but not Gαi or Gαs, pathway.
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: 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: P-Y
authors.initials: PY
authors.lastname: Tseng
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: 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; Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Wuhan 430030, China.
authors.forename: B
authors.initials: B
authors.lastname: Shu
authors.affiliation: Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA; Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing 100050, China.
authors.forename: T
authors.initials: T
authors.lastname: Zhang
authors.affiliation: Nanjing University of Chinese Medicine, 138 Xianlin Road, Nanjing, Jiangsu 210023, China.
authors.forename: Z
authors.initials: Z
authors.lastname: Tang
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: Department of Anesthesiology, Beijing Chaoyang Hospital, Capital Medical University, Beijing 100020, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Wang
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 21287, 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; D015220:Calcium Channels / Q000378:metabolism*; D002478:Cells, Cultured; D004195:Disease Models, Animal; D005727:Ganglia, Spinal / Q000187:drug effects / Q000502:physiology* / Q000503:physiopathology; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006930:Hyperalgesia / Q000188:drug therapy / Q000503:physiopathology; D008297:Male; D018345:Mice, Knockout; D008822:Mice, Transgenic; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D018408:Patch-Clamp Techniques; D017207:Rats, Sprague-Dawley; D043562:Receptors, G-Protein-Coupled / Q000819:agonists / Q000378:metabolism*; D013127:Spinal Nerves / Q000293:injuries; D010738:Type C Phospholipases / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D015220:Calcium Channels; D049452:Green Fluorescent Proteins; D043562:Receptors, G-Protein-Coupled; D010738:Type C Phospholipases; C470192:Mrgprx1 protein, mouse; C000591603:Mrgprc protein, rat
keywords: MrgC; PLC; calcium channel; dorsal root ganglion; pain