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 (0.001–100 nM, a dipeptide, MrgC-selective agonist) was significantly reduced by pretreatment with a phospholipase C inhibitor (U73122, 1 μM), but not by its inactive analogue (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 (100 nM) was partially reduced by pretreatment with a Gβγ blocker (gallein, 100 μM). However, applying a depolarizing prepulse and blocking the Gαi and Gαs pathways with pertussis toxin (0.5 μg/mL) and cholera toxin (0.5 μg/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 phospholipase C, but not Gαi or Gαs, pathway.

Orthosteric muscarinic receptor activation by the insect repellent IR3535 opens new prospects in insecticide-based vector control

“…2b,c,h). Therefore, we examined whether increase in the imput membrane resistance can be blocked by pretreatment with a Gβγ blocker, gallein [29][30][31] . Interestingly, similar results to those of GDP-β-S www.nature.com/scientificreports www.nature.com/scientificreports/ were obtained with gallein (10 µM; Fig.…”

Tlx3 Function in the Dorsal Root Ganglion is Pivotal to Itch and Pain Sensations

“…Genetic deletion of Mrgpr cluster, especially MrgprC11, induced prolonged inflammatory mechanical allodynia and heat hyperalgesia compared to the wild type mice, whereas neuropathic pain remained normal (Liu et al, 2009 ). Injection of MrgprC11 agonists, such as BAM8-22 and JHU58, markedly inhibited calcium current in DRG neurons and further attenuated inflammatory pain hypersensitivity, suggesting that MrgprC11 might induce analgesia in persistent pain through an endogenous inhibitory pathway (Li et al, 2015 ).…”

Targeting human Mas-related G protein-coupled receptor X1 to inhibit persistent pain

“…MRGPRs comprise a family of orphan G protein-coupled receptors (GPCRs) and include many genes in humans and rodents (7-11), but their physiological functions are only partially known. Many Mrgpr genes (mouse MrgprA3, MrgprC11, and MrgprD; rat MrgprC; and human MrgprX1) are expressed specifically in small-diameter primary sensory dorsal root ganglia (DRG) neurons (presumably nociceptive) in rodents, monkeys, and humans discovered using various approaches, and have been reported to play important roles in pain and itch (6, 10, 12-19).Animal studies suggest that a potential drug target is the MRGPRC in trigeminal ganglia and DRG (6,20,21). Activation of MRGPRC with agonists by intrathecal (i.th.)…”