1
|
Liu TT, Qiu CY, Li XM, Hu WP. CXCL10 Enhances Acid-Sensing Ion Channel Currents in Rat Dorsal Root. Mol Neurobiol 2024:10.1007/s12035-024-04390-3. [PMID: 39046700 DOI: 10.1007/s12035-024-04390-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Accepted: 07/21/2024] [Indexed: 07/25/2024]
Abstract
Both CXCL10/CXCR3 and acid-sensing ion channels (ASICs) are expressed in nociceptive sensory neurons and participate in various pain processes, but it is still unclear whether there is a link between them. Herein, we report that CXCL10 enhances the electrophysiological activity of ASICs in rat dorsal root ganglia (DRG) neurons. A brief (10 min) application of CXCL10 increased acid-evoked ASIC currents in a concentration-dependent manner. CXCL10 increased the maximum response of ASICs to acidic stimuli without changing their sensitivity. CXCL10 enhanced ASIC currents in DRG cells through CXCR3, as this enhancement was completely blocked by AMG487, a selective CXCR3 antagonist. CXCL10 also increased ASIC3 currents in CHO cells coexpressing ASIC3 and CXCR3 but not in cells expressing ASIC3 alone. The CXCL10-mediated increase in ASIC currents was prevented by the application of either the G protein inhibitor GDP-β-S or the p38 mitogen-activated protein kinase (MAPK) inhibitor SB202190 but not by the ERK inhibitor U0126 or the JNK inhibitor SP600125. Moreover, CXCL10 increased the number of action potentials triggered by acidic stimuli via CXCR3. CXCL10 dose-dependently exacerbated acid-induced nociceptive behavior in rats through peripheral CXCR3. These results indicated that CXCL10/CXCR3 signaling enhanced ASIC-mediated electrophysiological activity in DRG neurons and nociception in rats via a p38 MAPK-dependent pathway, revealing a novel mechanism underlying pain. CXCL10/CXCR3 signaling may be an effective target in the treatment of pain associated with tissue acidification.
Collapse
Affiliation(s)
- Ting-Ting Liu
- School of Basic Medical Sciences, Xianning Medical College, Hubei University of Science and Technology, 88 Xianning Road, Xianning, 437100, Hubei, People's Republic of China
| | - Chun-Yu Qiu
- School of Basic Medical Sciences, Xianning Medical College, Hubei University of Science and Technology, 88 Xianning Road, Xianning, 437100, Hubei, People's Republic of China
| | - Xue-Mei Li
- School of Basic Medical Sciences, Xianning Medical College, Hubei University of Science and Technology, 88 Xianning Road, Xianning, 437100, Hubei, People's Republic of China
| | - Wang-Ping Hu
- School of Basic Medical Sciences, Xianning Medical College, Hubei University of Science and Technology, 88 Xianning Road, Xianning, 437100, Hubei, People's Republic of China.
- Hubei College of Chinese Medicine, 87 Xueyuan Road, Jingzhou, 434020, Hubei, People's Republic of China.
| |
Collapse
|
2
|
Slivicki RA, Yi J, Brings VE, Huynh PN, Gereau RW. The cannabinoid agonist CB-13 produces peripherally mediated analgesia in mice but elicits tolerance and signs of central nervous system activity with repeated dosing. Pain 2022; 163:1603-1621. [PMID: 34961756 PMCID: PMC9281468 DOI: 10.1097/j.pain.0000000000002550] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 11/24/2021] [Indexed: 11/25/2022]
Abstract
ABSTRACT Activation of cannabinoid receptor type 1 (CB 1 ) produces analgesia in a variety of preclinical models of pain; however, engagement of central CB 1 receptors is accompanied by unwanted side effects, such as psychoactivity, tolerance, and dependence. Therefore, some efforts to develop novel analgesics have focused on targeting peripheral CB 1 receptors to circumvent central CB 1 -related side effects. In the present study, we evaluated the effects of acute and repeated dosing with the peripherally selective CB 1 -preferring agonist CB-13 on nociception and central CB 1 -related phenotypes in a model of inflammatory pain in mice. We also evaluated cellular mechanisms underlying CB-13-induced antinociception in vitro using cultured mouse dorsal root ganglion neurons. CB-13 reduced inflammation-induced mechanical allodynia in male and female mice in a peripheral CB 1 -receptor-dependent manner and relieved inflammatory thermal hyperalgesia. In cultured mouse dorsal root ganglion neurons, CB-13 reduced TRPV1 sensitization and neuronal hyperexcitability induced by the inflammatory mediator prostaglandin E 2 , providing potential mechanistic explanations for the analgesic actions of peripheral CB 1 receptor activation. With acute dosing, phenotypes associated with central CB 1 receptor activation occurred only at a dose of CB-13 approximately 10-fold the ED 50 for reducing allodynia. Strikingly, repeated dosing resulted in both analgesic tolerance and CB 1 receptor dependence, even at a dose that did not produce central CB 1 -receptor-mediated phenotypes on acute dosing. This suggests that repeated CB-13 dosing leads to increased CNS exposure and unwanted engagement of central CB 1 receptors. Thus, caution is warranted regarding therapeutic use of CB-13 with the goal of avoiding CNS side effects. Nonetheless, the clear analgesic effect of acute peripheral CB 1 receptor activation suggests that peripherally restricted cannabinoids are a viable target for novel analgesic development.
Collapse
Affiliation(s)
- Richard A. Slivicki
- Washington University Pain Center and Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO
| | - Jiwon Yi
- Washington University Pain Center and Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO
- Neuroscience Graduate Program, Division of Biology & Biomedical Sciences, Washington University School of Medicine, St. Louis, MO
| | - Victoria E. Brings
- Washington University Pain Center and Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO
| | - Phuong Nhu Huynh
- Washington University Pain Center and Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO
| | - Robert W. Gereau
- Washington University Pain Center and Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO
- Department of Neuroscience, Washington University, St. Louis, MO
- Department of Biomedical Engineering, Washington University, St. Louis, MO
| |
Collapse
|
3
|
Ford ZK, Reker AN, Chen S, Kadakia F, Bunk A, Davidson S. Cannabinoid Receptor 1 Expression in Human Dorsal Root Ganglia and CB13-Induced Bidirectional Modulation of Sensory Neuron Activity. FRONTIERS IN PAIN RESEARCH 2022; 2:721332. [PMID: 35295508 PMCID: PMC8915700 DOI: 10.3389/fpain.2021.721332] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Accepted: 10/08/2021] [Indexed: 12/23/2022] Open
Abstract
Cannabinoid receptors have been identified as potential targets for analgesia from studies on animal physiology and behavior, and from human clinical trials. Here, we sought to improve translational understanding of the mechanisms of cannabinoid-mediated peripheral analgesia. Human lumbar dorsal root ganglia were rapidly recovered from organ donors to perform physiological and anatomical investigations into the potential for cannabinoids to mediate analgesia at the level of the peripheral nervous system. Anatomical characterization of in situ gene expression and immunoreactivity showed that 61 and 53% of human sensory neurons express the CB1 gene and receptor, respectively. Calcium influx evoked by the algogen capsaicin was measured by Fura-2AM in dissociated human sensory neurons pre-exposed to the inflammatory mediator prostaglandin E2 (PGE2) alone or together with CB13 (1 μM), a cannabinoid agonist with limited blood–brain barrier permeability. Both a higher proportion of neurons and a greater magnitude of response to capsaicin were observed after exposure to CB13, indicating cannabinoid-mediated sensitization. In contrast, membrane properties measured by patch-clamp electrophysiology demonstrated that CB13 suppressed excitability and reduced action potential discharge in PGE2-pre-incubated sensory neurons, suggesting the suppression of sensitization. This bidirectional modulation of sensory neuron activity suggests that cannabinoids may suppress overall membrane excitability while simultaneously enhancing responsivity to TRPV1-mediated stimuli. We conclude that peripherally restricted cannabinoids may have both pro- and anti-nociceptive effects in human sensory neurons.
Collapse
Affiliation(s)
- Zachary K Ford
- Neuroscience Graduate Program, College of Medicine, University of Cincinnati, Cincinnati, OH, United States
| | - Ashlie N Reker
- Department of Anesthesiology and Pain Research Center, University of Cincinnati, College of Medicine, Cincinnati, OH, United States
| | - Sisi Chen
- Department of Anesthesiology and Pain Research Center, University of Cincinnati, College of Medicine, Cincinnati, OH, United States
| | - Feni Kadakia
- Neuroscience Graduate Program, College of Medicine, University of Cincinnati, Cincinnati, OH, United States
| | - Alexander Bunk
- Neuroscience Graduate Program, College of Medicine, University of Cincinnati, Cincinnati, OH, United States
| | - Steve Davidson
- Neuroscience Graduate Program, College of Medicine, University of Cincinnati, Cincinnati, OH, United States.,Department of Anesthesiology and Pain Research Center, University of Cincinnati, College of Medicine, Cincinnati, OH, United States
| |
Collapse
|
4
|
Cullinan MM, Klipp RC, Bankston JR. Regulation of acid-sensing ion channels by protein binding partners. Channels (Austin) 2021; 15:635-647. [PMID: 34704535 PMCID: PMC8555555 DOI: 10.1080/19336950.2021.1976946] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
Acid-sensing ion channels (ASICs) are a family of proton-gated cation channels that contribute to a diverse array of functions including pain sensation, cell death during ischemia, and more broadly to neurotransmission in the central nervous system. There is an increasing interest in understanding the physiological regulatory mechanisms of this family of channels. ASICs have relatively short N- and C-termini, yet a number of proteins have been shown to interact with these domains both in vitro and in vivo. These proteins can impact ASIC gating, localization, cell-surface expression, and regulation. Like all ion channels, it is important to understand the cellular context under which ASICs function in neurons and other cells. Here we will review what is known about a number of these potentially important regulatory molecules.
Collapse
Affiliation(s)
- Megan M Cullinan
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Robert C Klipp
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - John R Bankston
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| |
Collapse
|
5
|
Yamamoto T, Mulpuri Y, Izraylev M, Li Q, Simonian M, Kramme C, Schmidt BL, Seltzman HH, Spigelman I. Selective targeting of peripheral cannabinoid receptors prevents behavioral symptoms and sensitization of trigeminal neurons in mouse models of migraine and medication overuse headache. Pain 2021; 162:2246-2262. [PMID: 33534356 PMCID: PMC8277668 DOI: 10.1097/j.pain.0000000000002214] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 01/19/2021] [Indexed: 01/03/2023]
Abstract
ABSTRACT Migraine affects ∼15% of the world's population greatly diminishing their quality of life. Current preventative treatments are effective in only a subset of migraine patients, and although cannabinoids seem beneficial in alleviating migraine symptoms, central nervous system side effects limit their widespread use. We developed peripherally restricted cannabinoids (PRCBs) that relieve chronic pain symptoms of cancer and neuropathies, without appreciable central nervous system side effects or tolerance development. Here, we determined PRCB effectiveness in alleviating hypersensitivity symptoms in mouse models of migraine and medication overuse headache. Long-term glyceryl trinitrate (GTN, 10 mg/kg) administration led to increased sensitivity to mechanical stimuli and increased expression of phosphorylated protein kinase A, neuronal nitric oxide synthase, and transient receptor potential ankyrin 1 proteins in trigeminal ganglia. Peripherally restricted cannabinoid pretreatment, but not posttreatment, prevented behavioral and biochemical correlates of GTN-induced sensitization. Low pH-activated and allyl isothiocyanate-activated currents in acutely isolated trigeminal neurons were reversibly attenuated by PRCB application. Long-term GTN treatment significantly enhanced these currents. Long-term sumatriptan treatment also led to the development of allodynia to mechanical and cold stimuli that was slowly reversible after sumatriptan discontinuation. Subsequent challenge with a previously ineffective low-dose GTN (0.1-0.3 mg/kg) revealed latent behavioral sensitization and increased expression of phosphorylated protein kinase A, neuronal nitric oxide synthase, and transient receptor potential ankyrin 1 proteins in trigeminal ganglia. Peripherally restricted cannabinoid pretreatment prevented all behavioral and biochemical correlates of allodynia and latent sensitization. Importantly, long-term PRCB treatment alone did not produce any behavioral or biochemical signs of sensitization. These data validate peripheral cannabinoid receptors as potential therapeutic targets in migraine and medication overuse headache.
Collapse
Affiliation(s)
- Toru Yamamoto
- Division of Oral Biology & Medicine, School of Dentistry, University of California, Los Angeles, Los Angeles, CA
| | - Yatendra Mulpuri
- Division of Oral Biology & Medicine, School of Dentistry, University of California, Los Angeles, Los Angeles, CA
| | - Mikhail Izraylev
- Division of Oral Biology & Medicine, School of Dentistry, University of California, Los Angeles, Los Angeles, CA
| | - Qianyi Li
- Division of Oral Biology & Medicine, School of Dentistry, University of California, Los Angeles, Los Angeles, CA
| | - Menooa Simonian
- Division of Oral Biology & Medicine, School of Dentistry, University of California, Los Angeles, Los Angeles, CA
| | - Christian Kramme
- Division of Oral Biology & Medicine, School of Dentistry, University of California, Los Angeles, Los Angeles, CA
| | - Brian L. Schmidt
- Department of Oral & Maxillofacial Surgery and Bluestone Center for Clinical Research, New York University College of Dentistry, New York, NY
| | - Herbert H. Seltzman
- Organic and Medicinal Chemistry, Research Triangle Institute, Research Triangle Park, NC
| | - Igor Spigelman
- Division of Oral Biology & Medicine, School of Dentistry, University of California, Los Angeles, Los Angeles, CA
- Brain Research Institute, University of California, Los Angeles, Los Angeles, CA
| |
Collapse
|
6
|
Przykaza Ł, Kozniewska E. Ligands of the Neuropeptide Y Y2 Receptors as a Potential Multitarget Therapeutic Approach for the Protection of the Neurovascular Unit Against Acute Ischemia/Reperfusion: View from the Perspective of the Laboratory Bench. Transl Stroke Res 2021; 13:12-24. [PMID: 34292517 PMCID: PMC8766383 DOI: 10.1007/s12975-021-00930-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 07/11/2021] [Accepted: 07/12/2021] [Indexed: 01/02/2023]
Abstract
Ischemic stroke is the third leading cause of death and disability worldwide, with no available satisfactory prevention or treatment approach. The current treatment is limited to the use of “reperfusion methods,” i.e., an intravenous or intra-arterial infusion of a fibrinolytic agent, mechanical removal of the clot by thrombectomy, or a combination of both methods. It should be stressed, however, that only approximately 5% of all acute strokes are eligible for fibrinolytic treatment and fewer than 10% for thrombectomy. Despite the tremendous progress in understanding of the pathomechanisms of cerebral ischemia, the promising results of basic research on neuroprotection are not currently transferable to human stroke. A possible explanation for this failure is that experiments on in vivo animal models involve healthy young animals, and the experimental protocols seldom consider the importance of protecting the whole neurovascular unit (NVU), which ensures intracranial homeostasis and is seriously damaged by ischemia/reperfusion. One of the endogenous protective systems activated during ischemia and in neurodegenerative diseases is represented by neuropeptide Y (NPY). It has been demonstrated that activation of NPY Y2 receptors (Y2R) by a specific ligand decreases the volume of the postischemic infarction and improves performance in functional tests of rats with arterial hypertension subjected to middle cerebral artery occlusion/reperfusion. This functional improvement suggests the protection of the NVU. In this review, we focus on NPY and discuss the potential, multidirectional protective effects of Y2R agonists against acute focal ischemia/reperfusion injury, with special reference to the NVU.
Collapse
Affiliation(s)
- Łukasz Przykaza
- Laboratory of Experimental and Clinical Neurosurgery, Mossakowski Medical Research Institute Polish Academy of Sciences, A. Pawińskiego Str. 5, 02-106, Warsaw, Poland
| | - Ewa Kozniewska
- Laboratory of Experimental and Clinical Neurosurgery, Mossakowski Medical Research Institute Polish Academy of Sciences, A. Pawińskiego Str. 5, 02-106, Warsaw, Poland.
| |
Collapse
|
7
|
Xia LP, Luo H, Ma Q, Xie YK, Li W, Hu H, Xu ZZ. GPR151 in nociceptors modulates neuropathic pain via regulating P2X3 function and microglial activation. Brain 2021; 144:3405-3420. [PMID: 34244727 DOI: 10.1093/brain/awab245] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Revised: 05/17/2021] [Accepted: 06/01/2021] [Indexed: 11/14/2022] Open
Abstract
Neuropathic pain is a major health problem that affects up to 7-10% of the population worldwide. Currently, neuropathic pain is difficult to treat due to its elusive mechanisms. Here we report that orphan G protein-coupled receptor 151 (GPR151) in nociceptive sensory neurons controls neuropathic pain induced by nerve injury. GPR151 was mainly expressed in nonpeptidergic C-fiber dorsal root ganglion (DRG) neurons and highly upregulated after nerve injury. Importantly, conditional knockout of Gpr151 in adult nociceptive sensory neurons significantly alleviated chronic constriction injury (CCI)-induced neuropathic pain-like behavior but did not affect basal nociception. Moreover, GPR151 in DRG neurons was required for CCI-induced neuronal hyperexcitability and upregulation of colony-stimulating factor 1 (CSF1), which is necessary for microglial activation in the spinal cord after nerve injury. Mechanistically, GPR151 coupled with P2X3 ion channels and promoted their functional activities in neuropathic pain-like hypersensitivity. Knockout of Gpr151 suppressed P2X3-mediated calcium elevation and spontaneous pain behavior in CCI mice. Conversely, overexpression of Gpr151 significantly enhanced P2X3-mediated calcium elevation and DRG neuronal excitability. Furthermore, knockdown of P2X3 in DRGs reversed CCI-induced CSF1 upregulation, spinal microglial activation, and neuropathic pain-like behavior. Finally, the co-expression of GPR151 and P2X3 was confirmed in small-diameter human DRG neurons, indicating the clinical relevance of our findings. Together, our results suggest that GPR151 in nociceptive DRG neurons plays a key role in the pathogenesis of neuropathic pain and could be a potential target for treating neuropathic pain.
Collapse
Affiliation(s)
- Li-Ping Xia
- Department of Neurobiology and Department of Anesthesiology of First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Hao Luo
- Department of Neurobiology and Department of Anesthesiology of First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Qiang Ma
- Department of Neurobiology and Department of Anesthesiology of First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Ya-Kai Xie
- Department of Neurobiology and Department of Anesthesiology of First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Wei Li
- Department of Neurobiology and Department of Anesthesiology of First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Hailan Hu
- Department of Neurobiology and Department of Anesthesiology of First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Zhen-Zhong Xu
- Department of Neurobiology and Department of Anesthesiology of First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, Zhejiang 310058, China
| |
Collapse
|
8
|
Wei S, Qiu CY, Jin Y, Liu TT, Hu WP. Dexmedetomidine Inhibits ASIC Activity via Activation of α 2A Adrenergic Receptors in Rat Dorsal Root Ganglion Neurons. Front Pharmacol 2021; 12:685460. [PMID: 34108881 PMCID: PMC8181722 DOI: 10.3389/fphar.2021.685460] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 05/11/2021] [Indexed: 01/13/2023] Open
Abstract
Dexmedetomidine (DEX), a selective α2 adrenergic receptor (α2-AR) agonist, has been shown to have peripheral analgesic effects in a variety of pain conditions. However, the precise molecular mechanisms have not yet been fully elucidated. Acid sensing ion channels (ASICs) are the major player in pain associated with tissue acidosis. Given that both α2-ARs and ASICs exist in dorsal root ganglia (DRG) neurons, we therefore investigated the effects of DEX on the functional activity of ASICs. Herein, whole-cell patch-clamp recordings demonstrated that DEX suppressed ASIC-mediated and acid-evoked currents and action potentials in dissociated rat DRG neurons. DEX shifted downwards concentration-response curve to protons, with a decrease of 35.83 ± 3.91% in the maximal current response to pH 4.5. DEX-induced inhibition of ASIC currents was blocked by the α2A-AR antagonist BRL44408 in DRG neurons. DEX also inhibited ASIC3 currents in CHO cells co-expressing ASIC3 and α2A-ARs, but not in ASIC3 transfected CHO cells without α2A-ARs expression. DEX-induced inhibition of ASIC currents was mimicked by the protein kinase A inhibitor H-89, and blocked by intracellular application of the Gi/o protein inhibitor pertussis toxin and the cAMP analog 8-Br-cAMP. In addition, peripherally administration of DEX dose-dependently relieved nociceptive responses to intraplantar injection of acetic acid in rats through local α2A-ARs. Our results indicated that DEX inhibited the functional activity of ASICs via α2A-ARs and intracellular Gi/o proteins and cAMP/protein kinase A signaling pathway in rat DRG neurons, which was a novel potential mechanism that probably mediated peripheral analgesia of DEX.
Collapse
Affiliation(s)
- Shuang Wei
- Research Center of Basic Medical Sciences, School of Basic Medical Sciences, Hubei University of Science and Technology, Xianning, China.,Department of Pharmacology, Hubei University of Science and Technology, Xianning, China
| | - Chun-Yu Qiu
- Research Center of Basic Medical Sciences, School of Basic Medical Sciences, Hubei University of Science and Technology, Xianning, China
| | - Ying Jin
- Research Center of Basic Medical Sciences, School of Basic Medical Sciences, Hubei University of Science and Technology, Xianning, China
| | - Ting-Ting Liu
- Research Center of Basic Medical Sciences, School of Basic Medical Sciences, Hubei University of Science and Technology, Xianning, China
| | - Wang-Ping Hu
- Research Center of Basic Medical Sciences, School of Basic Medical Sciences, Hubei University of Science and Technology, Xianning, China
| |
Collapse
|
9
|
Inhibition of ASIC-Mediated Currents by Activation of Somatostatin 2 Receptors in Rat Dorsal Root Ganglion Neurons. Mol Neurobiol 2021; 58:2107-2117. [PMID: 33411247 DOI: 10.1007/s12035-020-02257-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 12/09/2020] [Indexed: 12/18/2022]
Abstract
Somatostatin (SST) and its analogues like octreotide (OCT) have analgesic effect on a variety of pain through peripheral SST receptors (SSTRs). However, the precise molecular mechanisms have not yet been fully elucidated. This research aimed to identify possible antinociceptive mechanisms, showing functional links of the SSTR2 and acid-sensing ion channels (ASICs). Herein, we reported that OCT inhibited the electrophysiological activity of ASICs in rat dorsal root ganglia (DRG) neurons. OCT concentration-dependently decreased the peak amplitude of acid-evoked inward currents, which were mediated by ASICs. OCT shifted concentration-response curve to protons downwards, with a decrease of 36.53 ± 5.28% in the maximal current response to pH 4.5 in the presence of OCT. OCT inhibited ASIC-mediated currents through SSTR2, since the inhibition was blocked by Cyn 154806, a specific SSTR2 antagonist. The OCT inhibition of ASIC-mediated currents was mimicked by H-89, a membrane-permeable inhibitor of PKA, and reversed by internal treatment of an adenylyl cyclase activator forskolin or 8-Br-cAMP. OCT also decreased the number of action potentials induced by acid stimuli through SSTR2. Finally, peripheral administration of 20 μM OCT, but not 2 μM OCT, significantly relieved nociceptive responses to intraplantar injection of acetic acid in rats. This occurred through local activation of SSTR2 in the injected hindpaw and was reversed following co-application of Cyn 154806. Our results indicate that activation SSTR2 by OCT can inhibit the activity of ASICs via an intracellular cAMP and PKA signaling pathway in rat DRG neurons. These observations demonstrate a cross-talk between ASICs and SSTR2 in peripheral sensory neurons, which was a novel peripheral analgesic mechanism of SST and its analogues.
Collapse
|
10
|
Nociceptor Signalling through ion Channel Regulation via GPCRs. Int J Mol Sci 2019; 20:ijms20102488. [PMID: 31137507 PMCID: PMC6566991 DOI: 10.3390/ijms20102488] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 05/08/2019] [Accepted: 05/13/2019] [Indexed: 12/23/2022] Open
Abstract
The prime task of nociceptors is the transformation of noxious stimuli into action potentials that are propagated along the neurites of nociceptive neurons from the periphery to the spinal cord. This function of nociceptors relies on the coordinated operation of a variety of ion channels. In this review, we summarize how members of nine different families of ion channels expressed in sensory neurons contribute to nociception. Furthermore, data on 35 different types of G protein coupled receptors are presented, activation of which controls the gating of the aforementioned ion channels. These receptors are not only targeted by more than 20 separate endogenous modulators, but can also be affected by pharmacotherapeutic agents. Thereby, this review provides information on how ion channel modulation via G protein coupled receptors in nociceptors can be exploited to provide improved analgesic therapy.
Collapse
|
11
|
Guo L, Zhao L, Ming P, Hong L, Liu A, Li R. Sumatriptan inhibits the electrophysiological activity of ASICs in rat trigeminal ganglion neurons. Eur J Pharmacol 2018; 841:98-103. [PMID: 30336137 DOI: 10.1016/j.ejphar.2018.10.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 10/09/2018] [Accepted: 10/10/2018] [Indexed: 02/07/2023]
Abstract
Sumatriptan, a selective serotonin 5-HT1 receptor agonist, is an effective therapeutic for migraine attacks. However, the molecular mechanisms underlying sumatriptan migraine relief are still not fully understood. Here, we found that acid-sensing ion channels (ASICs), pH sensors, are peripheral targets of sumatriptan against migraine. Sumatriptan can inhibit the electrophysiological activity of ASICs in the trigeminal ganglion (TG) neurons. In the present study, sumatriptan decreased proton-gated currents mediated by ASICs in a concentration-dependent manner. In addition, sumatriptan shifted concentration-response curves for protons downwards, with a decrease of 37.3 ± 4.6% in the maximum current response but with no significant change in the pH0.5 value. Sumatriptan inhibition of ASIC currents was blocked by 5-HT1D receptor antagonist BRL 15572, but not by 5-HT1B antagonist SB 224289. Moreover, the sumatriptan inhibition of ASICs can be mimicked by the 5-HT1D receptor agonist L-694,247, but not by the 5-HT1B agonist CP-93129. Sumatriptan inhibition of ASIC currents was also reversed by G-protein αi subunit inhibitor PTX and 8-Br-cAMP, suggesting the inhibition may involve the intracellular signal transduction. Finally, sumatriptan decreased the number of action potentials induced by acid stimuli in rat TG neurons. Our results indicated that the anti-migraine drug, sumatriptan, inhibited ASICs in rat TG neurons via 5-HT1D receptor subtype and a cAMP-dependent signal pathway. These observations add to the understanding of the mechanisms that underlie the clinical effectiveness of anti-migraine sumatriptan.
Collapse
Affiliation(s)
- Longhua Guo
- Clinical Laboratory, The People's Hospital of Longhua, Shenzhen, PR China; Key Laboratory on Innovation Research for Medicine Laboratory Technology, The People's Hospital of Longhua, Shenzhen, PR China
| | - Ling Zhao
- Clinical Laboratory, The People's Hospital of Longhua, Shenzhen, PR China; Key Laboratory on Innovation Research for Medicine Laboratory Technology, The People's Hospital of Longhua, Shenzhen, PR China
| | - Pinghong Ming
- Clinical Laboratory, The People's Hospital of Longhua, Shenzhen, PR China; Key Laboratory on Innovation Research for Medicine Laboratory Technology, The People's Hospital of Longhua, Shenzhen, PR China
| | - Ling Hong
- Clinical Laboratory, The People's Hospital of Longhua, Shenzhen, PR China; Key Laboratory on Innovation Research for Medicine Laboratory Technology, The People's Hospital of Longhua, Shenzhen, PR China
| | - Aisheng Liu
- Clinical Laboratory, The People's Hospital of Longhua, Shenzhen, PR China; Key Laboratory on Innovation Research for Medicine Laboratory Technology, The People's Hospital of Longhua, Shenzhen, PR China
| | - Rukai Li
- Clinical Laboratory, Shenzhen Baoan Shiyan People's Hospital, No. 11 Jixiang Road, Shiyan street, Baoan District, Shenzhen, PR China.
| |
Collapse
|
12
|
Acid-Sensing Ion Channels as Potential Therapeutic Targets in Neurodegeneration and Neuroinflammation. Mediators Inflamm 2017; 2017:3728096. [PMID: 29056828 PMCID: PMC5625748 DOI: 10.1155/2017/3728096] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2017] [Revised: 07/29/2017] [Accepted: 08/13/2017] [Indexed: 12/21/2022] Open
Abstract
Acid-sensing ion channels (ASICs) are a family of proton-sensing channels that are voltage insensitive, cation selective (mostly permeable to Na+), and nonspecifically blocked by amiloride. Derived from 5 genes (ACCN1-5), 7 subunits have been identified, 1a, 1b, 2a, 2b, 3, 4, and 5, that are widely expressed in the peripheral and central nervous system as well as other tissues. Over the years, different studies have shown that activation of these channels is linked to various physiological and pathological processes, such as memory, learning, fear, anxiety, ischemia, and multiple sclerosis to name a few, so their potential as therapeutic targets is increasing. This review focuses on recent advances that have helped us to better understand the role played by ASICs in different pathologies related to neurodegenerative diseases, inflammatory processes, and pain.
Collapse
|
13
|
Regulation of divalent metal transporter-1 by serine phosphorylation. Biochem J 2016; 473:4243-4254. [PMID: 27681840 PMCID: PMC5103878 DOI: 10.1042/bcj20160674] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 09/22/2016] [Accepted: 09/28/2016] [Indexed: 01/14/2023]
Abstract
Divalent metal transporter-1 (DMT1) mediates dietary iron uptake across the intestinal mucosa and facilitates peripheral delivery of iron released by transferrin in the endosome. Here, we report that classical cannabinoids (Δ9-tetrahydrocannabinol, Δ9-THC), nonclassical cannabinoids (CP 55,940), aminoalkylindoles (WIN 55,212-2) and endocannabinoids (anandamide) reduce 55Fe and 54Mn uptake by HEK293T(DMT1) cells stably expressing the transporter. siRNA knockdown of cannabinoid receptor type 2 (CB2) abrogated inhibition. CB2 is a G-protein (GTP-binding protein)-coupled receptor that negatively regulates signal transduction cascades involving serine/threonine kinases. Immunoprecipitation experiments showed that DMT1 is serine-phosphorylated under basal conditions, but that treatment with Δ9-THC reduced phosphorylation. Site-directed mutation of predicted DMT1 phosphosites further showed that substitution of serine with alanine at N-terminal position 43 (S43A) abolished basal phosphorylation. Concordantly, both the rate and extent of 55Fe uptake in cells expressing DMT1(S43A) was reduced compared with those expressing wild-type DMT1. Among kinase inhibitors that affected DMT1-mediated iron uptake, staurosporine also reduced DMT1 phosphorylation confirming a role for serine phosphorylation in iron transport regulation. These combined data indicate that phosphorylation at serine 43 of DMT1 promotes transport activity, whereas dephosphorylation is associated with loss of iron uptake. Since anti-inflammatory actions mediated through CB2 would be associated with reduced DMT1 phosphorylation, we postulate that this pathway provides a means to reduce oxidative stress by limiting iron uptake.
Collapse
|
14
|
Lei Z, Li X, Wang G, Fei J, Meng T, Zhang X, Yu J, Yu J, Li J. Inhibition of acid-sensing ion channel currents by propofol in rat dorsal root ganglion neurons. Clin Exp Pharmacol Physiol 2014; 41:295-300. [PMID: 24552301 DOI: 10.1111/1440-1681.12215] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2013] [Revised: 01/16/2014] [Accepted: 02/09/2014] [Indexed: 11/30/2022]
Abstract
Acid-sensing ion channels (ASICs), part of the epithelial sodium channel/degenerin family, are activated by extracellular protons. The ASICs play a significant role in the acidosis-mediated perception of pain. The anaesthetic agent propofol also exerts antinociceptive effects, but the underlying mechanisms for this effect are not clear. We used whole-cell patch clamping to investigate the effect of propofol on proton-gated currents in: (i) rat dorsal root ganglion (DRG) neurons; and (ii) HEK293 cells transfected with either ASIC1a or ASIC3. Propofol inhibited the amplitude of proton-gated currents in DRG neurons, but did not change the sensitivity of ASICs to H(+). Notably, propofol altered acid-evoked excitability of rat DRG neurons and decreased the number of action potentials induced by acid stimuli. In addition, we demonstrated that propofol inhibited ASICs by directly binding with these channels in HEK293 cells. These results suggest that propofol inhibits proton-gated currents in DRG neurons and that inhibition of proton-gated currents explains, in part, the antinociceptive effects of propofol in primary afferent neurons.
Collapse
Affiliation(s)
- Zhen Lei
- Department of Anesthesiology, Qilu Hospital, Shandong University, Jinan, Shandong, China
| | | | | | | | | | | | | | | | | |
Collapse
|
15
|
Kellenberger S, Schild L. International Union of Basic and Clinical Pharmacology. XCI. Structure, Function, and Pharmacology of Acid-Sensing Ion Channels and the Epithelial Na+ Channel. Pharmacol Rev 2014; 67:1-35. [DOI: 10.1124/pr.114.009225] [Citation(s) in RCA: 193] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
|
16
|
Qiu F, Liu TT, Qu ZW, Qiu CY, Yang Z, Hu WP. Gastrodin inhibits the activity of acid-sensing ion channels in rat primary sensory neurons. Eur J Pharmacol 2014; 731:50-7. [PMID: 24642360 DOI: 10.1016/j.ejphar.2014.02.044] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Revised: 01/23/2014] [Accepted: 02/23/2014] [Indexed: 01/24/2023]
Abstract
Acid-sensing ion channels (ASICs), a family of proton-gated cation channels, are believed to mediate pain caused by extracellular acidification. Gastrodin is a main bioactive constituent of the traditional herbal Gastrodia elata Blume, which has been widely used in Oriental countries for centuries. As an analgesic, gastrodin has been used clinically to treat pain such as migraine and headache. However, the mechanisms underlying analgesic action of gastrodin are still poorly understood. Here, we have found that gastrodin inhibited the activity of native ASICs in rat dorsal root ganglion (DRG) neurons. Gastrodin dose-dependently inhibited proton-gated currents mediated by ASICs. Gastrodin shifted the proton concentration-response curve downwards, with a decrease of 36.92 ± 6.23% in the maximum current response but with no significant change in the pH0.5 value. Moreover, gastrodin altered acid-evoked membrane excitability of rat DRG neurons and caused a significant decrease in the amplitude of the depolarization and the number of action potentials induced by acid stimuli. Finally, peripheral applied gastrodin relieved pain evoked by intraplantar injection of acetic acid in rats. Our results indicate that gastrodin can inhibit the activity of ASICs in the primary sensory neurons, which provided a novel mechanism underlying analgesic action of gastrodin.
Collapse
Affiliation(s)
- Fang Qiu
- Department of Pharmacology, Hubei University of Science and Technology, 88 Xianning Road, Xianning 437100, Hubei, PR China; College of Life Sciences, Hubei University, Wuhan 430062, Hubei, PR China
| | - Ting-Ting Liu
- Department of Pharmacology, Hubei University of Science and Technology, 88 Xianning Road, Xianning 437100, Hubei, PR China
| | - Zu-Wei Qu
- Department of Pharmacology, Hubei University of Science and Technology, 88 Xianning Road, Xianning 437100, Hubei, PR China
| | - Chun-Yu Qiu
- Department of Pharmacology, Hubei University of Science and Technology, 88 Xianning Road, Xianning 437100, Hubei, PR China
| | - Zhifan Yang
- College of Life Sciences, Hubei University, Wuhan 430062, Hubei, PR China
| | - Wang-Ping Hu
- Department of Pharmacology, Hubei University of Science and Technology, 88 Xianning Road, Xianning 437100, Hubei, PR China.
| |
Collapse
|
17
|
Sousa-Valente J, Varga A, Ananthan K, Khajuria A, Nagy I. Anandamide in primary sensory neurons: too much of a good thing? Eur J Neurosci 2014; 39:409-18. [DOI: 10.1111/ejn.12467] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Revised: 11/22/2013] [Accepted: 12/02/2013] [Indexed: 01/01/2023]
Affiliation(s)
- João Sousa-Valente
- Section of Anaesthetics, Pain Medicine and Intensive Care; Department of Surgery and Cancer; Imperial College London; 369 Fulham Road London SW10 9NH UK
| | - Angelika Varga
- Section of Anaesthetics, Pain Medicine and Intensive Care; Department of Surgery and Cancer; Imperial College London; 369 Fulham Road London SW10 9NH UK
| | - Kajaluxy Ananthan
- Section of Anaesthetics, Pain Medicine and Intensive Care; Department of Surgery and Cancer; Imperial College London; 369 Fulham Road London SW10 9NH UK
| | - Ankur Khajuria
- Section of Anaesthetics, Pain Medicine and Intensive Care; Department of Surgery and Cancer; Imperial College London; 369 Fulham Road London SW10 9NH UK
| | - Istvan Nagy
- Section of Anaesthetics, Pain Medicine and Intensive Care; Department of Surgery and Cancer; Imperial College London; 369 Fulham Road London SW10 9NH UK
| |
Collapse
|
18
|
Cai Q, Qiu CY, Qiu F, Liu TT, Qu ZW, Liu YM, Hu WP. Morphine inhibits acid-sensing ion channel currents in rat dorsal root ganglion neurons. Brain Res 2014; 1554:12-20. [PMID: 24491633 DOI: 10.1016/j.brainres.2014.01.042] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Revised: 01/18/2014] [Accepted: 01/24/2014] [Indexed: 02/08/2023]
Abstract
Extracellular acidosis is a common feature in pain-generating pathological conditions. Acid-sensing ion channels (ASICs), pH sensors, are distributed in peripheral sensory neurons and participate in nociception. Morphine exerts potent analgesic effects through the activation of opioid receptors for various pain conditions. A cross-talk between ASICs and opioid receptors in peripheral sensory neurons has not been shown so far. Here, we have found that morphine inhibits the activity of native ASICs in rat dorsal root ganglion (DRG) neurons. Morphine dose-dependently inhibited proton-gated currents mediated by ASICs in the presence of the TRPV1 inhibitor capsazepine. Morphine shifted the proton concentration-response curve downwards, with a decrease of 51.4±3.8% in the maximum current response but with no significant change in the pH0.5 value. Another μ-opioid receptor agonist DAMGO induced a similar decrease in ASIC currents compared with morphine. The morphine inhibition of ASIC currents was blocked by naloxone, a specific opioid receptor antagonist. Pretreatment of forskolin, an adenylyl cyclase activator, or the addition of cAMP reversed the inhibitory effect of morphine. Moreover, morphine altered acid-evoked excitability of rat DRG neurons and decreased the number of action potentials induced by acid stimuli. Finally, peripheral applied morphine relieved pain evoked by intraplantar of acetic acid in rats. Our results indicate that morphine can inhibit the activity of ASICs via μ-opioid receptor and cAMP dependent signal pathway. These observations demonstrate a cross-talk between ASICs and opioid receptors in peripheral sensory neurons, which was a novel analgesic mechanism of morphine.
Collapse
Affiliation(s)
- Qi Cai
- Department of Pharmacology, Hubei University of Science and Technology, 88 Xianning Road, Xianning 437100, Hubei, PR China; Neurology Department, Zhongnan Hospital of Wuhan University, Wuhan 430071, Hubei, PR China
| | - Chun-Yu Qiu
- Department of Pharmacology, Hubei University of Science and Technology, 88 Xianning Road, Xianning 437100, Hubei, PR China
| | - Fang Qiu
- Department of Pharmacology, Hubei University of Science and Technology, 88 Xianning Road, Xianning 437100, Hubei, PR China
| | - Ting-Ting Liu
- Department of Pharmacology, Hubei University of Science and Technology, 88 Xianning Road, Xianning 437100, Hubei, PR China
| | - Zu-Wei Qu
- Department of Pharmacology, Hubei University of Science and Technology, 88 Xianning Road, Xianning 437100, Hubei, PR China
| | - Yu-Min Liu
- Neurology Department, Zhongnan Hospital of Wuhan University, Wuhan 430071, Hubei, PR China.
| | - Wang-Ping Hu
- Department of Pharmacology, Hubei University of Science and Technology, 88 Xianning Road, Xianning 437100, Hubei, PR China.
| |
Collapse
|
19
|
Peripheral gating of pain signals by endogenous lipid mediators. Nat Neurosci 2014; 17:164-74. [PMID: 24473264 DOI: 10.1038/nn.3612] [Citation(s) in RCA: 176] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Accepted: 11/22/2013] [Indexed: 12/13/2022]
Abstract
Primary sensory afferents and their neighboring host-defense cells are a rich source of lipid-derived mediators that contribute to the sensation of pain caused by tissue damage and inflammation. But an increasing number of lipid molecules have been shown to act in an opposite way, to suppress the inflammatory process, restore homeostasis in damaged tissues and attenuate pain sensitivity by regulating neural pathways that transmit nociceptive signals from the periphery of the body to the CNS. Here we review the molecular and cellular mechanisms that contribute to the modulatory actions of lipid mediators in peripheral nociceptive signaling.
Collapse
|
20
|
Kweon HJ, Suh BC. Acid-sensing ion channels (ASICs): therapeutic targets for neurological diseases and their regulation. BMB Rep 2014; 46:295-304. [PMID: 23790972 PMCID: PMC4133903 DOI: 10.5483/bmbrep.2013.46.6.121] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Extracellular acidification occurs not only in pathological conditions such as inflammation and brain ischemia, but also in normal physiological conditions such as synaptic transmission. Acid-sensing ion channels (ASICs) can detect a broad range of physiological pH changes during pathological and synaptic cellular activities. ASICs are voltage-independent, proton-gated cation channels widely expressed throughout the central and peripheral nervous system. Activation of ASICs is involved in pain perception, synaptic plasticity, learning and memory, fear, ischemic neuronal injury, seizure termination, neuronal degeneration, and mechanosensation. Therefore, ASICs emerge as potential therapeutic targets for manipulating pain and neurological diseases. The activity of these channels can be regulated by many factors such as lactate, Zn2+, and Phe-Met-Arg-Phe amide (FMRFamide)-like neuropeptides by interacting with the channel’s large extracellular loop. ASICs are also modulated by G protein-coupled receptors such as CB1 cannabinoid receptors and 5-HT2. This review focuses on the physiological roles of ASICs and the molecular mechanisms by which these channels are regulated. [BMB Reports 2013; 46(6): 295-304]
Collapse
Affiliation(s)
- Hae-Jin Kweon
- Department of Brain Science, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 711-873, Korea
| | | |
Collapse
|
21
|
Kan L, Mutso AA, McGuire TL, Apkarian AV, Kessler JA. Opioid signaling in mast cells regulates injury responses associated with heterotopic ossification. Inflamm Res 2013; 63:207-15. [PMID: 24327087 DOI: 10.1007/s00011-013-0690-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Revised: 11/18/2013] [Accepted: 11/20/2013] [Indexed: 10/25/2022] Open
Abstract
INTRODUCTION Previous studies found that neuron specific enolase promoter (Nse-BMP4) transgenic mice have increased expression of the nociceptive mediator, substance P and exaggerated local injury responses associated with heterotopic ossification (HO). It is of interest great to know the pain responses in these mice and how the opioid signaling is involved in the downstream events such as mast cell (MC) activation. MATERIALS AND METHODS This study utilized a transgenic mouse model of HO in which BMP4 is expressed under the control of the Nse-BMP4. The tactile sensitivity and the cold sensitivity of the mice were measured in a classic inflammatory pain model (carrageenan solution injected into the plantar surface of the left hind paw). The MC activation and the expression profiles of different components in the opioid signaling were demonstrated through routine histology and immunohistochemistry and Western blotting, in the superficial and deep muscle injury models. RESULTS We found that the pain responses in these mice were paradoxically attenuated or unchanged, and we also found increased expression of both Methionine Enkephalin (Met-Enk), and the μ-opioid receptor (MOR). Met-Enk and MOR both co-localized within activated MCs in limb tissues. Further, Nse-BMP4;MOR(-/-) double mutant mice showed attenuated MC activation and had a significant reduction in HO formation in response to injuries. CONCLUSIONS These observations suggest that opioid signaling may play a key role in MC activation and the downstream inflammatory responses associated with HO. In addition to providing insight into the role of MC activation and associated injury responses in HO, these findings suggest opioid signaling as a potential therapeutic target in HO and possibly others disorders involving MC activation.
Collapse
Affiliation(s)
- Lixin Kan
- Department of Neurology, Northwestern University, Ward Building 10-233, 303 East Chicago Avenue, Chicago, IL, 60611-3008, USA,
| | | | | | | | | |
Collapse
|