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Steele HR, Han L. The signaling pathway and polymorphisms of Mrgprs. Neurosci Lett 2020; 744:135562. [PMID: 33388356 DOI: 10.1016/j.neulet.2020.135562] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 12/02/2020] [Accepted: 12/08/2020] [Indexed: 12/31/2022]
Abstract
Mas-related G protein-coupled receptors (Mrgprs) are a family of receptors implicated in a diverse array of human diseases. Since their discovery in 2001, great progress has been made in determining their relation to human disease. Vital for Mrgprs therapeutic efforts across all disease disciplines is a thorough understanding of Mrgprs signal transduction pathways and polymorphisms, as these offer insights into new drug candidates, existing discrepancies in drug response, and differences in disease susceptibility. In this review, we discuss the current state of knowledge regarding Mrgprs signaling pathways and polymorphisms.
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Affiliation(s)
- Haley R Steele
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, United States
| | - Liang Han
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, United States.
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Szczepanska-Sadowska E, Cudnoch-Jedrzejewska A, Sadowski B. Differential role of specific cardiovascular neuropeptides in pain regulation: Relevance to cardiovascular diseases. Neuropeptides 2020; 81:102046. [PMID: 32284215 DOI: 10.1016/j.npep.2020.102046] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2019] [Revised: 03/27/2020] [Accepted: 03/29/2020] [Indexed: 12/11/2022]
Abstract
In many instances, the perception of pain is disproportionate to the strength of the algesic stimulus. Excessive or inadequate pain sensation is frequently observed in cardiovascular diseases, especially in coronary ischemia. The mechanisms responsible for individual differences in the perception of cardiovascular pain are not well recognized. Cardiovascular disorders may provoke pain in multiple ways engaging molecules released locally in the heart due to tissue ischemia, inflammation or cellular stress, and through neurogenic and endocrine mechanisms brought into action by hemodynamic disturbances. Cardiovascular neuropeptides, namely angiotensin II (Ang II), angiotensin-(1-7) [Ang-(1-7)], vasopressin, oxytocin, and orexins belong to this group. Although participation of these peptides in the regulation of circulation and pain has been firmly established, their mutual interaction in the regulation of pain in cardiovascular diseases has not been profoundly analyzed. In the present review we discuss the regulation of the release, and mechanisms of the central and systemic actions of these peptides on the cardiovascular system in the context of their central and peripheral nociceptive (Ang II) and antinociceptive [Ang-(1-7), vasopressin, oxytocin, orexins] properties. We also consider the possibility that they may play a significant role in the modulation of pain in cardiovascular diseases. The rationale for focusing attention on these very compounds was based on the following premises (1) cardiovascular disturbances influence the release of these peptides (2) they regulate vascular tone and cardiac function and can influence the intensity of ischemia - the factor initiating pain signals in the cardiovascular system, (3) they differentially modulate nociception through peripheral and central mechanisms, and their effect strongly depends on specific receptors and site of action. Accordingly, an altered release of these peptides and/or pharmacological blockade of their receptors may have a significant but different impact on individual sensation of pain and comfort of an individual patient.
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Affiliation(s)
- Ewa Szczepanska-Sadowska
- Department of Experimental and Clinical Physiology, Laboratory of Centre for Preclinical Research, Medical University of Warsaw, Banacha 1b, Warsaw, Poland.
| | - Agnieszka Cudnoch-Jedrzejewska
- Department of Experimental and Clinical Physiology, Laboratory of Centre for Preclinical Research, Medical University of Warsaw, Banacha 1b, Warsaw, Poland
| | - Bogdan Sadowski
- School of Engineering and Health, Bitwy Warszawskiej 1920 r. 18, Warsaw, Poland
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Electroacupuncture Alleviates Experimental Chronic Inflammatory Pain by Inhibiting Calcium Voltage-Gated Channel-Mediated Inflammation. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2020; 2020:7061972. [PMID: 32104194 PMCID: PMC7035529 DOI: 10.1155/2020/7061972] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2019] [Revised: 12/01/2019] [Accepted: 12/10/2019] [Indexed: 12/17/2022]
Abstract
Background Both experimental and clinical studies have shown that electroacupuncture (EA) administration ameliorates chronic inflammatory pain (CIP). However, the multifaceted mechanism underlying the effects of EA on CIP is poorly understood. In this study, the mRNA transcriptome was used to study various therapeutic targets of EA. Methods Using RNA-sequencing, protein-coding mRNA expression profiles of the L4-L5 dorsal root ganglion (DRG) were examined in the control (CN), complete Freund's adjuvant- (CFA-) induced CIP, and EA-treated CIP groups. A series of bioinformatics analyses was performed; “EA-reversed upregulated genes with CIP” (up-DEGs) and “EA-reversed downregulated genes with CIP” (down-DEGs) were identified. Thereafter, based on up-DEGs and down-DEGs, biological functions and signaling pathways were enriched using gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) pathway analyses. Results In total, 189 DEGs were identified, including 134 up- and 55 down-DEGs, which were enriched in arachidonic acid metabolism (rno00590), glutamatergic synapse (rno04724), serotonergic synapse (rno04726), FoxO signaling pathway (rno04068), insulin signaling pathway (rno04910), amyotrophic lateral sclerosis (rno05014), cholinergic synapse (rno04725), ECM-receptor interaction (rno04512), and choline metabolism in cancer (rno05231). Conclusion We identified a few GOs, pathways, and genes that could play key roles in the amelioration of CIP by EA. Hence, this study may provide a theoretical basis for CIP amelioration by EA.
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The Ubiquitination of Spinal MrgC Alleviates Bone Cancer Pain and Reduces Intracellular Calcium Concentration in Spinal Neurons in Mice. Neurochem Res 2019; 44:2527-2535. [PMID: 31515677 DOI: 10.1007/s11064-019-02869-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 08/30/2019] [Accepted: 09/05/2019] [Indexed: 01/12/2023]
Abstract
Mas-related G-protein-coupled receptor subtype C (MrgC) has been shown to play an important role in the development of bone cancer pain. Ubiquitination is reported to participate in pain. However, whether MrgC ubiquitination plays a role in bone cancer pain remains unclear. To answer this question, we designed and performed this study. Osteosarcoma cells were implanted into the intramedullary space of the right femurs of C3H/HeJ mice to induce progressive bone cancer pain. MrgC agonist bovine adrenal medulla 8-22 (BAM 8-22) or MrgC antagonist anti-MrgC antibody were injected intrathecally on day 14 after bone cancer pain was successfully induced. The pain behaviors, the MrgC ubiquitination levels and intracellular calcium concentration in spinal neurons were measured before and after injection, respectively. With comparison to normal and sham group, mice in tumor group exhibited serious bone cancer pain on day 14, and the level of MrgC ubiquitination and intracellular calcium concentration in spinal neurons was significantly higher. Intrathecal injection of BAM 8-22 significantly alleviated bone cancer pain, increased the MrgC ubiquitination level and decreased intracellular calcium concentration in spinal neurons; however, these effects were reversed by administration of anti-MrgC antibody. Our study reveals that MrgC ubiquitination participates in the production and maintenance of bone cancer pain in mice, possibly through the regulation of intracellular calcium concentration in mice spinal neurons.
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Al-Shamlan F, El-Hashim AZ. Bradykinin sensitizes the cough reflex via a B 2 receptor dependent activation of TRPV1 and TRPA1 channels through metabolites of cyclooxygenase and 12-lipoxygenase. Respir Res 2019; 20:110. [PMID: 31170972 PMCID: PMC6551914 DOI: 10.1186/s12931-019-1060-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 04/28/2019] [Indexed: 01/10/2023] Open
Abstract
Background Inhaled bradykinin (BK) has been reported to both sensitize and induce cough but whether BK can centrally sensitize the cough reflex is not fully established. In this study, using a conscious guinea-pig model of cough, we investigated the role of BK in the central sensitization of the cough reflex and in airway obstruction. Methods Drugs were administered, to guinea pigs, by the intracerebroventricular (i.c.v.) route. Aerosolized citric acid (0.2 M) was used to induce cough in a whole-body plethysmograph box, following i.c.v. infusion of drugs. An automated analyser recorded both cough and airway obstruction simultaneously. Results BK, administered by the i.c.v. route, dose-dependently enhanced the citric acid-induced cough and airway obstruction. This effect was inhibited following i.c.v. pretreatment with a B2 receptor antagonist, TRPV1 and TRPA1 channels antagonists and cyclooxygenase (COX) and 12-lipoxygenase (12-LOX) inhibitors. Furthermore, co-administration of submaximal doses of the TRPV1 and TRPA1 antagonists or the COX and 12-LOX inhibitors resulted in a greater inhibition of both cough reflex and airway obstruction. Conclusions Our findings show that central BK administration sensitizes cough and enhances airway obstruction via a B2 receptor/TRPV1 and/or TRPA1 channels which are coupled via metabolites of COX and/or 12-LOX enzymes. In addition, combined blockade of TRPV1 and TRPA1 or COX and 12-LOX resulted in a greater inhibitory effect of both cough and airway obstruction. These results indicate that central B2 receptors, TRPV1/TRPA1 channels and COX/12-LOX enzymes may represent potential therapeutic targets for the treatment of cough hypersensitivity. Graphical abstract ![]()
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Affiliation(s)
- Fajer Al-Shamlan
- Department of Pharmacology and Therapeutics, Faculty of Pharmacy, Kuwait University, P.O. BOX 24923, 13110, Safat, Kuwait
| | - Ahmed Z El-Hashim
- Department of Pharmacology and Therapeutics, Faculty of Pharmacy, Kuwait University, P.O. BOX 24923, 13110, Safat, Kuwait.
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Zhang Y, Wang M, Lu Q, Li Q, Lin M, Huang J, Hong Y. Inhibitory Effects of Mas-Related Gene C Receptor on Chronic Morphine-Induced Spinal Glial Activation in Rats. J Pharmacol Exp Ther 2018; 368:237-245. [DOI: 10.1124/jpet.118.252494] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2018] [Accepted: 11/20/2018] [Indexed: 12/20/2022] Open
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Involvement of MrgprC in Electroacupuncture Analgesia for Attenuating CFA-Induced Thermal Hyperalgesia by Suppressing the TRPV1 Pathway. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2018; 2018:9102107. [PMID: 29619074 PMCID: PMC5829339 DOI: 10.1155/2018/9102107] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2017] [Revised: 12/22/2017] [Accepted: 01/04/2018] [Indexed: 01/20/2023]
Abstract
Mas-related G-protein-coupled receptor C (MrgprC) plays an important role in modulating chronic inflammatory pain. Electroacupuncture (EA) has a satisfactory analgesic effect on chronic pain. This study aimed to investigate the involvement of MrgprC and its transient receptor potential vanilloid 1 (TRPV1) pathway in EA analgesia in chronic inflammatory pain. Chronic inflammatory pain was induced by subcutaneously injecting complete Freund's adjuvant (CFA) into the left hind paw. EA (2/100 Hz) stimulation was administered. MrgprC siRNAs were intrathecally administered to inhibit MrgprC expression, and bovine adrenal medulla 8-22 (BAM8-22) was used to activate MrgprC. The mechanical allodynia was decreased by EA significantly since day 3. The piled analgesic effect of EA was partially blocked by 6 intrathecal administrations of MrgprC siRNA. Both EA and BAM8-22 could downregulate the expression of TRPV1 and PKC in both the DRG and the SCDH. Both EA and BAM8-22 could also decrease the TRPV1 translocation and p-TRPV1 level in both the DRG and the SCDH. The effects of EA on PKCε, TRPV1 translocation, and p-TRPV1 in both the DRG and the SCDH were reversed by MrgprC siRNA. The results indicated that MrgprC played crucial roles in chronic pain modulation and was involved in EA analgesia partially through the regulation of TRPV1 function at the DRG and SCDH levels.
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Gao JR, Qin XJ, Jiang H, Wang T, Song JM, Xu SZ. The effects of Qi Teng Xiao Zhuo granules, traditional Chinese medicine, on the expression of genes in chronic glomerulonephritis rats. JOURNAL OF ETHNOPHARMACOLOGY 2016; 193:140-149. [PMID: 27497640 DOI: 10.1016/j.jep.2016.08.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Revised: 07/24/2016] [Accepted: 08/03/2016] [Indexed: 06/06/2023]
Abstract
BACKGROUND AND AIM Chronic glomerulonephritis (CGN) is a primary glomerular disease that is related to immune-mediated inflammatory diseases. Qi Teng Xiao Zhuo granules have been proposed as a prescription of traditional Chinese medicine for treatment of CGN, but the comprehensive molecular mechanism underlying this therapeutic effect is not clear to date. The aim of this study was to evaluate and analyze the possible roles and molecular mechanisms of Qi Teng Xiao Zhuo granule-mediated treatment of CGN induced by adriamycin in rats. METHODS For gene expression analysis, four samples of glomerular tissue from rats in the Qi Teng Xiao Zhuo granule group and four samples each from the adriamycin treated and control groups were hybridized with Agilent Rat 4×44K whole genome microarrays. KEGG and Gene Ontology (GO) analyses and LIMMA, String and Cytoscape software were used to analyze the functional microarray data and screen differentially expressed genes. Hub genes were identified using Pathway Studio software. Real-time PCR was performed to verify the selected genes. RESULTS Microarray gene expression analysis showed that Pnoc, Cacfd1, Fos, Igll1, Lcn2, and Syk were among the most downregulated genes in the Qi Teng Xiao Zhuo granule group compared with the adriamycin treated group, whereas Cyp2c7, Hsd3b6, Acsm5, and Ugt2b15 were significantly upregulated. Functional analysis demonstrated that metabolism of xenobiotics by cytochrome P450, the B cell receptor signaling pathway, and cytokine-cytokine receptor interaction pathways were significantly downregulated in the Qi Teng Xiao Zhuo granule group and that GO terms related to positive regulation of immune response, immune response-activating signal transduction, cell differentiation, cell cycle, proliferation, and adhesion were significantly affected. Fos and Syk were considered to be potential hub genes. CONCLUSIONS In the adriamycin-induced CGN rat model, comprehensive molecular mechanisms were involved with complex gene expression alterations containing many altered pathways and GO terms. However, how Qi Teng Xiao Zhuo granules regulate these events warrants further investigation.
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Affiliation(s)
- Jia-Rong Gao
- Department of Pharmacy, The First Affiliated Hospital of Anhui University of Chinese Medicine, 117 Meishan Road, Hefei 230031, China.
| | - Xiu-Juan Qin
- College of Pharmacy, Anhui university of Chinese Medicine, 103 Meishan Road, Hefei, China
| | - Hui Jiang
- Department of Pharmacy, The First Affiliated Hospital of Anhui University of Chinese Medicine, 117 Meishan Road, Hefei 230031, China
| | - Ting Wang
- College of Pharmacy, Anhui university of Chinese Medicine, 103 Meishan Road, Hefei, China
| | - Jun-Mei Song
- College of Pharmacy, Anhui university of Chinese Medicine, 103 Meishan Road, Hefei, China
| | - Shuang-Zhi Xu
- College of Pharmacy, Anhui university of Chinese Medicine, 103 Meishan Road, Hefei, China
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Rezq S, Abdel-Rahman AA. Rostral Ventrolateral Medulla EP3 Receptor Mediates the Sympathoexcitatory and Pressor Effects of Prostaglandin E2 in Conscious Rats. J Pharmacol Exp Ther 2016; 359:290-299. [PMID: 27572469 DOI: 10.1124/jpet.116.233502] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 08/25/2016] [Indexed: 12/13/2022] Open
Abstract
Whereas few studies have dealt with the central sympathoexcitatory action of the inflammatory prostanoid prostaglandin E2 (PGE2), there is no information on the expression and cardiovascular function of different PGE2 (EP) receptors in one of the major cardiovascular-regulating nuclei, the rostral ventrolateral medulla (RVLM). The current study aimed at filling this knowledge gap as well as elucidating the implicated molecular mechanisms. To achieve these goals, we showed the expression of EP2, EP3, and EP4 receptors in the RVLM and investigated their cardiovascular roles in conscious rats, ex vivo as well as in cultured PC12 cells. Intra-RVLM PGE2 significantly increased blood pressure and sympathetic dominance (spectral analysis). Studies with selective EP receptor subtype agonists and antagonists showed that these PGE2-evoked responses were only replicated by intra-RVLM activation of the EP3 receptor with its agonist sulprostone. The RVLM of PGE2-treated rats exhibited increases in c-Fos expression and extracellular signal-regulated kinase 1/2 and neuronal nitric oxide synthase phosphorylation along with oxidative stress, and PGE2 increased l-glutamate release in PC12 cells (surrogates of RVLM neurons). Abrogation of the PGE2-evoked pressor and biochemical responses only occurred following EP3 receptor blockade (N-[(5-Bromo-2-methoxyphenyl)sulfonyl]-3-[2-(2-naphthalenylmethyl)phenyl]-2-propenamide, L-798106). These findings suggest the dependence of RVLM PGE2-mediated sympathoexcitation/pressor response on local EP3 receptor signaling in conscious rats, and highlight central EP3 receptor blockade as a potential therapeutic modality for hypertension management.
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Affiliation(s)
- Samar Rezq
- Department of Pharmacology, School of Medicine, East Carolina University, Greenville, North Carolina
| | - Abdel A Abdel-Rahman
- Department of Pharmacology, School of Medicine, East Carolina University, Greenville, North Carolina
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Reversal of neurochemical alterations in the spinal dorsal horn and dorsal root ganglia by Mas-related gene (Mrg) receptors in a rat model of spinal nerve injury. Neurobiol Dis 2016; 91:274-83. [DOI: 10.1016/j.nbd.2016.03.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Revised: 03/12/2016] [Accepted: 03/21/2016] [Indexed: 12/17/2022] Open
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Sun Y, Jiang M, Hou B, Lu C, Lei Y, Ma Z, Gu X. Mas-Related Gene (Mrg) C Activation Attenuates Bone Cancer Pain via Modulating Gi and NR2B. PLoS One 2016; 11:e0154851. [PMID: 27152740 PMCID: PMC4859570 DOI: 10.1371/journal.pone.0154851] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2015] [Accepted: 04/20/2016] [Indexed: 01/02/2023] Open
Abstract
Objective This study is to investigate the role of Mas-related gene (Mrg) C in the pathogenesis and treatment of bone cancer pain (BCP). Methods BCP mouse model was established by osteosarcoma cell inoculation. Pain-related behaviors were assessed with the spontaneous lifting behavior test and mechanical allodynia test. Expression levels of MrgC, Gi, and NR2B in the spinal cord were detected with Western blot analysis and immunohistochemistry. Results Pain-related behavior tests showed significantly increased spontaneous flinches (NSF) and decreased paw withdrawal mechanical threshold (PWMT) in mouse models of BCP. Western blot analysis showed that, compared with the control group and before modeling, all the expression levels of MrgC, Gi, and NR2B in the spinal cord of BCP mice were dramatically elevated, which were especially increased at day 7 after operation and thereafter, in a time-dependent manner. Moreover, the treatment of MrgC agonist BAM8-22 significantly up-regulated Gi and down-regulated NR2B expression levels, in the spinal cord of BCP mice, in a time-dependent manner. On the other hand, anti-MrgC significantly down-regulated Gi expression, while dramatically up-regulated NR2B expression, in the BCP mice. Similar results were obtained from the immunohistochemical detection. Importantly, BAM8-22 significantly attenuated the nociceptive behaviors in the BCP mice. Conclusion Our results indicated the MrgC-mediated Gi and NR2B expression alterations in the BCP mice, which might contribute to the pain hypersensitivity. These findings may provide a novel strategy for the treatment of BCP in clinic.
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Affiliation(s)
- Yu'e Sun
- Department of Anaesthesiology, the Affiliated Drum-Tower Hospital of Medical College of Nanjing University, Nanjing 210008, Jiangsu, China
| | - Ming Jiang
- Department of Anaesthesiology, the Affiliated Drum-Tower Hospital of Medical College of Nanjing University, Nanjing 210008, Jiangsu, China
| | - Bailing Hou
- Department of Anaesthesiology, the Affiliated Drum-Tower Hospital of Medical College of Nanjing University, Nanjing 210008, Jiangsu, China
| | - Cui'e Lu
- Department of Anaesthesiology, the Affiliated Drum-Tower Hospital of Medical College of Nanjing University, Nanjing 210008, Jiangsu, China
| | - Yishan Lei
- Department of Anaesthesiology, the Affiliated Drum-Tower Hospital of Medical College of Nanjing University, Nanjing 210008, Jiangsu, China
| | - Zhengliang Ma
- Department of Anaesthesiology, the Affiliated Drum-Tower Hospital of Medical College of Nanjing University, Nanjing 210008, Jiangsu, China
| | - Xiaoping Gu
- Department of Anaesthesiology, the Affiliated Drum-Tower Hospital of Medical College of Nanjing University, Nanjing 210008, Jiangsu, China
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Wang D, Xue Y, Chen Y, Ruan L, Hong Y. Mas-related gene (Mrg) C receptors inhibit mechanical allodynia and spinal microglia activation in the early phase of neuropathic pain in rats. Neurosci Lett 2016; 618:115-121. [PMID: 26952974 DOI: 10.1016/j.neulet.2016.03.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Revised: 03/01/2016] [Accepted: 03/02/2016] [Indexed: 02/06/2023]
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.
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Affiliation(s)
- Dongmei Wang
- College of Life Sciences and Provincial Key Laboratory of Developmental Biology and Neuroscience, Fujian Normal University Fuzhou, Fujian 350108, People's Republic of China
| | - Yaping Xue
- College of Life Sciences and Provincial Key Laboratory of Developmental Biology and Neuroscience, Fujian Normal University Fuzhou, Fujian 350108, People's Republic of China
| | - Yajuan Chen
- College of Life Sciences and Provincial Key Laboratory of Developmental Biology and Neuroscience, Fujian Normal University Fuzhou, Fujian 350108, People's Republic of China
| | - Liqin Ruan
- College of Life Sciences and Provincial Key Laboratory of Developmental Biology and Neuroscience, Fujian Normal University Fuzhou, Fujian 350108, People's Republic of China
| | - Yanguo Hong
- College of Life Sciences and Provincial Key Laboratory of Developmental Biology and Neuroscience, Fujian Normal University Fuzhou, Fujian 350108, People's Republic of China.
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