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Tibbs GR, Uprety R, Warren JD, Beyer NP, Joyce RL, Ferrer MA, Mellado W, Wong VSC, Goldberg DC, Cohen MW, Costa CJ, Li Z, Zhang G, Dephoure NE, Barman DN, Sun D, Ingólfsson HI, Sauve AA, Willis DE, Goldstein PA. An anchor-tether 'hindered' HCN1 inhibitor is antihyperalgesic in a rat spared nerve injury neuropathic pain model. Br J Anaesth 2023; 131:745-763. [PMID: 37567808 PMCID: PMC10541997 DOI: 10.1016/j.bja.2023.06.067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 06/20/2023] [Accepted: 06/29/2023] [Indexed: 08/13/2023] Open
Abstract
BACKGROUND Neuropathic pain impairs quality of life, is widely prevalent, and incurs significant costs. Current pharmacological therapies have poor/no efficacy and significant adverse effects; safe and effective alternatives are needed. Hyperpolarisation-activated cyclic nucleotide-regulated (HCN) channels are causally implicated in some forms of peripherally mediated neuropathic pain. Whilst 2,6-substituted phenols, such as 2,6-di-tert-butylphenol (26DTB-P), selectively inhibit HCN1 gating and are antihyperalgesic, the development of therapeutically tolerable, HCN-selective antihyperalgesics based on their inverse agonist activity requires that such drugs spare the cardiac isoforms and do not cross the blood-brain barrier. METHODS In silico molecular dynamics simulation, in vitro electrophysiology, and in vivo rat spared nerve injury methods were used to test whether 'hindered' variants of 26DTB-P (wherein a hydrophilic 'anchor' is attached in the para-position of 26DTB-P via an acyl chain 'tether') had the desired properties. RESULTS Molecular dynamics simulation showed that membrane penetration of hindered 26DTB-Ps is controlled by a tethered diol anchor without elimination of head group rotational freedom. In vitro and in vivo analysis showed that BP4L-18:1:1, a variant wherein a diol anchor is attached to 26DTB-P via an 18-carbon tether, is an HCN1 inverse agonist and an orally available antihyperalgesic. With a CNS multiparameter optimisation score of 2.25, a >100-fold lower drug load in the brain vs blood, and an absence of adverse cardiovascular or CNS effects, BP4L-18:1:1 was shown to be poorly CNS penetrant and cardiac sparing. CONCLUSIONS These findings provide a proof-of-concept demonstration that anchor-tethered drugs are a new chemotype for treatment of disorders involving membrane targets.
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Affiliation(s)
- Gareth R Tibbs
- Department of Anesthesiology, Weill Cornell Medicine, New York, NY, USA
| | - Rajendra Uprety
- Department of Pharmacology, Weill Cornell Medicine, New York, NY, USA
| | - J David Warren
- Department of Biochemistry, Weill Cornell Medicine, New York, NY, USA
| | - Nicole P Beyer
- Department of Anesthesiology, Weill Cornell Medicine, New York, NY, USA
| | - Rebecca L Joyce
- Department of Anesthesiology, Weill Cornell Medicine, New York, NY, USA
| | - Matthew A Ferrer
- Department of Anesthesiology, Weill Cornell Medicine, New York, NY, USA
| | | | | | | | | | | | - Zhucui Li
- Department of Biochemistry, Weill Cornell Medicine, New York, NY, USA
| | - Guoan Zhang
- Department of Biochemistry, Weill Cornell Medicine, New York, NY, USA
| | - Noah E Dephoure
- Department of Biochemistry, Weill Cornell Medicine, New York, NY, USA; Sandra and Edward Meyer Cancer Center, Weill Cornell Medicine, New York, NY, USA
| | - Dipti N Barman
- Department of Biochemistry, Weill Cornell Medicine, New York, NY, USA
| | - Delin Sun
- Lawrence Livermore National Laboratory, Livermore, CA, USA
| | | | - Anthony A Sauve
- Department of Pharmacology, Weill Cornell Medicine, New York, NY, USA
| | - Dianna E Willis
- Burke Neurological Institute, White Plains, NY, USA; Feil Family Brain & Mind Research Institute, Weill Cornell Medicine, New York, NY, USA.
| | - Peter A Goldstein
- Department of Anesthesiology, Weill Cornell Medicine, New York, NY, USA; Feil Family Brain & Mind Research Institute, Weill Cornell Medicine, New York, NY, USA; Department of Medicine, Weill Cornell Medicine, New York, NY, USA.
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Zheng Y, Shao S, Zhang Y, Yuan S, Xing Y, Wang J, Qi X, Cui K, Tong J, Liu F, Cui S, Wan Y, Yi M. HCN2 Channels in the Ventral Hippocampal CA1 Regulate Nociceptive Hypersensitivity in Mice. Int J Mol Sci 2023; 24:13823. [PMID: 37762124 PMCID: PMC10531460 DOI: 10.3390/ijms241813823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 08/02/2023] [Accepted: 08/08/2023] [Indexed: 09/29/2023] Open
Abstract
Chronic pain is a significant health problem worldwide. Recent evidence has suggested that the ventral hippocampus is dysfunctional in humans and rodents, with decreased neuronal excitability and connectivity with other brain regions, parallel pain chronicity, and persistent nociceptive hypersensitivity. But the molecular mechanisms underlying hippocampal modulation of pain remain poorly elucidated. In this study, we used ex vivo whole-cell patch-clamp recording, immunofluorescence staining, and behavioral tests to examine whether hyperpolarization-activated cyclic nucleotide-gated channels 2 (HCN2) in the ventral hippocampal CA1 (vCA1) were involved in regulating nociceptive perception and CFA-induced inflammatory pain in mice. Reduced sag potential and firing rate of action potentials were observed in vCA1 pyramidal neurons from CFA-injected mice. Moreover, the expression of HCN2, but not HCN1, in vCA1 decreased in mice injected with CFA. HCN2 knockdown in vCA1 pyramidal neurons induced thermal hypersensitivity, whereas overexpression of HCN2 alleviated thermal hyperalgesia induced by intraplantar injection of CFA in mice. Our findings suggest that HCN2 in the vCA1 plays an active role in pain modulation and could be a promising target for the treatment of chronic pain.
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Affiliation(s)
- Yawen Zheng
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Peking University, Beijing 100191, China; (Y.Z.); (S.S.); (S.Y.); (Y.X.); (J.W.); (X.Q.); (K.C.); (J.T.); (F.L.); (S.C.); (Y.W.)
| | - Shan Shao
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Peking University, Beijing 100191, China; (Y.Z.); (S.S.); (S.Y.); (Y.X.); (J.W.); (X.Q.); (K.C.); (J.T.); (F.L.); (S.C.); (Y.W.)
| | - Yu Zhang
- National Health Commission Key Laboratory of Human Disease Comparative Medicine, Beijing Engineering Research Center for Experimental Animal Models of Human Critical Diseases, Institute of Laboratory Animal Science, Chinese Academy of Medical Science (CAMS) & Peking Union Medical College (PUMC), Beijing 100101, China;
| | - Shulu Yuan
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Peking University, Beijing 100191, China; (Y.Z.); (S.S.); (S.Y.); (Y.X.); (J.W.); (X.Q.); (K.C.); (J.T.); (F.L.); (S.C.); (Y.W.)
| | - Yuanwei Xing
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Peking University, Beijing 100191, China; (Y.Z.); (S.S.); (S.Y.); (Y.X.); (J.W.); (X.Q.); (K.C.); (J.T.); (F.L.); (S.C.); (Y.W.)
| | - Jiaxin Wang
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Peking University, Beijing 100191, China; (Y.Z.); (S.S.); (S.Y.); (Y.X.); (J.W.); (X.Q.); (K.C.); (J.T.); (F.L.); (S.C.); (Y.W.)
| | - Xuetao Qi
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Peking University, Beijing 100191, China; (Y.Z.); (S.S.); (S.Y.); (Y.X.); (J.W.); (X.Q.); (K.C.); (J.T.); (F.L.); (S.C.); (Y.W.)
| | - Kun Cui
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Peking University, Beijing 100191, China; (Y.Z.); (S.S.); (S.Y.); (Y.X.); (J.W.); (X.Q.); (K.C.); (J.T.); (F.L.); (S.C.); (Y.W.)
| | - Jifu Tong
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Peking University, Beijing 100191, China; (Y.Z.); (S.S.); (S.Y.); (Y.X.); (J.W.); (X.Q.); (K.C.); (J.T.); (F.L.); (S.C.); (Y.W.)
| | - Fengyu Liu
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Peking University, Beijing 100191, China; (Y.Z.); (S.S.); (S.Y.); (Y.X.); (J.W.); (X.Q.); (K.C.); (J.T.); (F.L.); (S.C.); (Y.W.)
| | - Shuang Cui
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Peking University, Beijing 100191, China; (Y.Z.); (S.S.); (S.Y.); (Y.X.); (J.W.); (X.Q.); (K.C.); (J.T.); (F.L.); (S.C.); (Y.W.)
| | - You Wan
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Peking University, Beijing 100191, China; (Y.Z.); (S.S.); (S.Y.); (Y.X.); (J.W.); (X.Q.); (K.C.); (J.T.); (F.L.); (S.C.); (Y.W.)
- Key Laboratory for Neuroscience, Ministry of Education/National Health Commission, Peking University, Beijing 100101, China
| | - Ming Yi
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Peking University, Beijing 100191, China; (Y.Z.); (S.S.); (S.Y.); (Y.X.); (J.W.); (X.Q.); (K.C.); (J.T.); (F.L.); (S.C.); (Y.W.)
- Key Laboratory for Neuroscience, Ministry of Education/National Health Commission, Peking University, Beijing 100101, China
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Joyce RL, Tibbs GR, David Warren J, Costa CJ, Aromolaran K, Lea Sanford R, Andersen OS, Li Z, Zhang G, Willis DE, Goldstein PA. Probucol is anti-hyperalgesic in a mouse peripheral nerve injury model of neuropathic pain. NEUROBIOLOGY OF PAIN (CAMBRIDGE, MASS.) 2023; 14:100141. [PMID: 38099280 PMCID: PMC10719523 DOI: 10.1016/j.ynpai.2023.100141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 07/25/2023] [Accepted: 08/01/2023] [Indexed: 12/17/2023]
Abstract
2,6-di-tert-butylphenol (2,6-DTBP) ameliorates mechanical allodynia and thermal hyperalgesia produced by partial sciatic nerve ligation in mice, and selectively inhibits HCN1 channel gating. We hypothesized that the clinically utilized non-anesthetic dimerized congener of 2,6-DTBP, probucol (2,6-di-tert-butyl-4-[2-(3,5-di-tert-butyl-4-hydroxyphenyl)sulfanylpropan-2-ylsulfanyl]phenol), would relieve the neuropathic phenotype that results from peripheral nerve damage, and that the anti-hyperalgesic efficacy in vivo would correlate with HCN1 channel inhibition in vitro. A single oral dose of probucol (800 mg/kg) relieved mechanical allodynia and thermal hyperalgesia in a mouse spared-nerve injury neuropathic pain model. While the low aqueous solubility of probucol precluded assessment of its possible interaction with HCN1 channels, our results, in conjunction with recent data demonstrating that probucol reduces lipopolysaccharide-induced mechanical allodynia and thermal hyperalgesia, support the testing/development of probucol as a non-opioid, oral antihyperalgesic albeit one of unknown mechanistic action.
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Affiliation(s)
- Rebecca L. Joyce
- Dept. of Anesthesiology, 1300 York Ave., Weill Cornell Medicine, New York, NY, USA
| | - Gareth R. Tibbs
- Dept. of Anesthesiology, 1300 York Ave., Weill Cornell Medicine, New York, NY, USA
| | - J. David Warren
- Dept. of Biochemistry, 413 E. 69th Street, Weill Cornell Medicine, New York, NY, USA
| | | | - Kelly Aromolaran
- Dept. of Anesthesiology, 1300 York Ave., Weill Cornell Medicine, New York, NY, USA
| | - R. Lea Sanford
- Dept. of Physiology & Biophysics, 1300 York Ave., Weill Cornell Medicine, New York, NY, USA
| | - Olaf S. Andersen
- Dept. of Physiology & Biophysics, 1300 York Ave., Weill Cornell Medicine, New York, NY, USA
| | - Zhucui Li
- Dept. of Biochemistry, 413 E. 69th Street, Weill Cornell Medicine, New York, NY, USA
| | - Guoan Zhang
- Dept. of Biochemistry, 413 E. 69th Street, Weill Cornell Medicine, New York, NY, USA
| | - Dianna E. Willis
- Burke Neurological Institute, 785 Mamaroneck Avenue, White Plains, NY, USA
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, NY, USA
| | - Peter A. Goldstein
- Dept. of Anesthesiology, 1300 York Ave., Weill Cornell Medicine, New York, NY, USA
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, NY, USA
- Dept. of Medicine, Weill Cornell Medicine, New York, NY, USA
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Wang X, Gan S, Zhang Z, Zhu P, Li CH, Luo F. HCN-Channel-Dependent Hyperexcitability of the Layer V Pyramidal Neurons in IL-mPFC Contributes to Fentanyl-Induced Hyperalgesia in Male Rats. Mol Neurobiol 2023; 60:2553-2571. [PMID: 36689134 DOI: 10.1007/s12035-023-03218-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 01/04/2023] [Indexed: 01/24/2023]
Abstract
Opioids are often first-line analgesics in pain therapy. However, prolonged use of opioids causes paradoxical pain, termed "opioid-induced hyperalgesia (OIH)." The infralimbic medial prefrontal cortex (IL-mPFC) has been suggested to be critical in inflammatory and neuropathic pain processing through its dynamic output from layer V pyramidal neurons. Whether OIH condition induces excitability changes of these output neurons and what mechanisms underlie these changes remains elusive. Here, with combination of patch-clamp recording, immunohistochemistry, as well as optogenetics, we revealed that IL-mPFC layer V pyramidal neurons exhibited hyperexcitability together with higher input resistance. In line with this, optogenetic and chemogenetic activation of these neurons aggravates behavioral hyperalgesia in male OIH rats. Inhibition of these neurons alleviates hyperalgesia in male OIH rats but exerts an opposite effect in male control rats. Electrophysiological analysis of hyperpolarization-activated cation current (Ih) demonstrated that decreased Ih is a prerequisite for the hyperexcitability of IL-mPFC output neurons. This decreased Ih was accompanied by a decrease in HCN1, but not HCN2, immunolabeling, in these neurons. In contrast, the application of HCN channel blocker increased the hyperalgesia threshold of male OIH rats. Consequently, we identified an HCN-channel-dependent hyperexcitability of IL-mPFC output neurons, which governs the development and maintenance of OIH in male rats.
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Affiliation(s)
- Xixi Wang
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Sifei Gan
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Zeru Zhang
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Pengfei Zhu
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Chen Hong Li
- The Laboratory of Membrane Ion Channels and Medicine, Key Laboratory of Cognitive Science, State Ethnic Affairs Commission, College of Biomedical Engineering, South-Central University for Nationalities, Wuhan, Hubei, China
| | - Fang Luo
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China.
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Tonomura S, Gu JG. Saltatory conduction and intrinsic electrophysiological properties at the nodes of ranvier of Aα/β-afferent fibers and Aα-efferent fibers in rat sciatic nerves. Mol Pain 2023; 19:17448069231187366. [PMID: 37369680 PMCID: PMC10413906 DOI: 10.1177/17448069231187366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 06/05/2023] [Accepted: 06/23/2023] [Indexed: 06/29/2023] Open
Abstract
Large-diameter myelinated fibers in sciatic nerves are composed of both Aα/β-afferent fibers and Aα-efferent fibers to convey sensory and motor impulses, respectively, via saltatory conduction for rapid leg responses. Saltatory conduction and electrophysiological properties at the nodes of Ranvier (NRs) of these sciatic nerve fibers have not been directly studied. We used ex vivo sciatic nerve preparations from rats and applied patch-clamp recordings at the NRs of both Aα/β-afferent fibers and Aα-efferent fibers in the sciatic nerves to characterize their saltatory conduction and intrinsic electrophysiological properties. The velocity and frequency of saltatory conduction in both types of fibers were similar. Resting membrane potentials (RMPs), input resistance, action potential (AP) threshold, and AP rheobase were also not significantly different at the NRs of the two types of fibers in the sciatic nerves. In comparison with Aα/β-afferent fibers, Aα-efferent fibers in the sciatic nerves show higher amplitude and broader width of APs at their NRs. At the NRs of both types of fibers, depolarizing voltages evoked transient inward currents followed by non-inactivating outward currents, and the inward currents and non-inactivating outward currents at the NRs were not significantly different between the two types of fibers. Using AP-clamp, inward currents during AP upstroke were found to be insignificant difference, but amplitudes of non-inactivating outward currents during AP repolarization were significantly lower at the NRs of Aα-efferent fibers than at the NRs of Aα/β-afferent fibers in the sciatic nerves. Collectively, saltatory conduction, ionic currents, and intrinsic electrophysiological properties at the NRs of Aα/β-afferent fibers and Aα-efferent fibers in the sciatic nerves are generally similar, but some differences were also observed.
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Affiliation(s)
- Sotatsu Tonomura
- Department of Anesthesiology and Perioperative Medicine, School of Medicine, University of Alabama, Birmingham, AL, USA
| | - Jianguo G Gu
- Department of Anesthesiology and Perioperative Medicine, School of Medicine, University of Alabama, Birmingham, AL, USA
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Kong L, Gao X, Qian Y, Sun W, You Z, Fan C. Biomechanical microenvironment in peripheral nerve regeneration: from pathophysiological understanding to tissue engineering development. Am J Cancer Res 2022; 12:4993-5014. [PMID: 35836812 PMCID: PMC9274750 DOI: 10.7150/thno.74571] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Accepted: 06/11/2022] [Indexed: 01/12/2023] Open
Abstract
Peripheral nerve injury (PNI) caused by trauma, chronic disease and other factors may lead to partial or complete loss of sensory, motor and autonomic functions, as well as neuropathic pain. Biological activities are always accompanied by mechanical stimulation, and biomechanical microenvironmental homeostasis plays a complicated role in tissue repair and regeneration. Recent studies have focused on the effects of biomechanical microenvironment on peripheral nervous system development and function maintenance, as well as neural regrowth following PNI. For example, biomechanical factors-induced cluster gene expression changes contribute to formation of peripheral nerve structure and maintenance of physiological function. In addition, extracellular matrix and cell responses to biomechanical microenvironment alterations after PNI directly trigger a series of cascades for the well-organized peripheral nerve regeneration (PNR) process, where cell adhesion molecules, cytoskeletons and mechanically gated ion channels serve as mechanosensitive units, mechanical effector including focal adhesion kinase (FAK) and yes-associated protein (YAP)/transcriptional coactivator with PDZ-binding motif (TAZ) as mechanotransduction elements. With the rapid development of tissue engineering techniques, a substantial number of PNR strategies such as aligned nerve guidance conduits, three-dimensional topological designs and piezoelectric scaffolds emerge expected to improve the neural biomechanical microenvironment in case of PNI. These tissue engineering nerve grafts display optimized mechanical properties and outstanding mechanomodulatory effects, but a few bottlenecks restrict their application scenes. In this review, the current understanding in biomechanical microenvironment homeostasis associated with peripheral nerve function and PNR is integrated, where we proposed the importance of balances of mechanosensitive elements, cytoskeletal structures, mechanotransduction cascades, and extracellular matrix components; a wide variety of promising tissue engineering strategies based on biomechanical modulation are introduced with some suggestions and prospects for future directions.
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Affiliation(s)
- Lingchi Kong
- Department of Orthopedics, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, 200233, China.,Shanghai Engineering Research Center for Orthopaedic Material Innovation and Tissue Regeneration, Shanghai, 200233, China.,Youth Science and Technology Innovation Studio of Shanghai Jiao Tong University School of Medicine, Shanghai, 200233, China
| | - Xin Gao
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Shanghai Belt and Road Joint Laboratory of Advanced Fiber and Low-dimension Materials, College of Materials Science and Engineering, Shanghai Engineering Research Center of Nano-Biomaterials and Regenerative Medicine, Donghua University, Shanghai, 201620, China
| | - Yun Qian
- Department of Orthopedics, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, 200233, China.,Shanghai Engineering Research Center for Orthopaedic Material Innovation and Tissue Regeneration, Shanghai, 200233, China.,Youth Science and Technology Innovation Studio of Shanghai Jiao Tong University School of Medicine, Shanghai, 200233, China.,✉ Corresponding authors: Yun Qian, E-mail: ; Wei Sun, E-mail: ; Zhengwei You, E-mail: ; Cunyi Fan, E-mail:
| | - Wei Sun
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Shanghai Belt and Road Joint Laboratory of Advanced Fiber and Low-dimension Materials, College of Materials Science and Engineering, Shanghai Engineering Research Center of Nano-Biomaterials and Regenerative Medicine, Donghua University, Shanghai, 201620, China.,✉ Corresponding authors: Yun Qian, E-mail: ; Wei Sun, E-mail: ; Zhengwei You, E-mail: ; Cunyi Fan, E-mail:
| | - Zhengwei You
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Shanghai Belt and Road Joint Laboratory of Advanced Fiber and Low-dimension Materials, College of Materials Science and Engineering, Shanghai Engineering Research Center of Nano-Biomaterials and Regenerative Medicine, Donghua University, Shanghai, 201620, China.,✉ Corresponding authors: Yun Qian, E-mail: ; Wei Sun, E-mail: ; Zhengwei You, E-mail: ; Cunyi Fan, E-mail:
| | - Cunyi Fan
- Department of Orthopedics, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, 200233, China.,Shanghai Engineering Research Center for Orthopaedic Material Innovation and Tissue Regeneration, Shanghai, 200233, China.,Youth Science and Technology Innovation Studio of Shanghai Jiao Tong University School of Medicine, Shanghai, 200233, China.,✉ Corresponding authors: Yun Qian, E-mail: ; Wei Sun, E-mail: ; Zhengwei You, E-mail: ; Cunyi Fan, E-mail:
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Lankford C, Houtman J, Baker SA. Identification of HCN1 as a 14-3-3 client. PLoS One 2022; 17:e0268335. [PMID: 35679272 PMCID: PMC9182292 DOI: 10.1371/journal.pone.0268335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Accepted: 04/28/2022] [Indexed: 11/19/2022] Open
Abstract
Hyperpolarization activated cyclic nucleotide-gated channel 1 (HCN1) is expressed throughout the nervous system and is critical for regulating neuronal excitability, with mutations being associated with multiple forms of epilepsy. Adaptive modulation of HCN1 has been observed, as has pathogenic dysregulation. While the mechanisms underlying this modulation remain incompletely understood, regulation of HCN1 has been shown to include phosphorylation. A candidate phosphorylation-dependent regulator of HCN1 channels is 14-3-3. We used bioinformatics to identify three potential 14-3-3 binding sites in HCN1. We confirmed that 14-3-3 could pull down HCN1 from multiple tissue sources and used HEK293 cells to detail the interaction. Two sites in the intrinsically disordered C-terminus of HCN1 were necessary and sufficient for a phosphorylation-dependent interaction with 14-3-3. The same region of HCN1 containing the 14-3-3 binding peptides is required for phosphorylation-independent protein degradation. We propose a model in which phosphorylation of mouse S810 and S867 (human S789 and S846) recruits 14-3-3 to inhibit a yet unidentified factor signaling for protein degradation, thus increasing the half-life of HCN1.
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Affiliation(s)
- Colten Lankford
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, Iowa, United States of America
| | - Jon Houtman
- Department of Microbiology and Immunology, University of Iowa, Iowa City, Iowa, United States of America
| | - Sheila A. Baker
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, Iowa, United States of America
- * E-mail:
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Roza C, Bernal L. Electrophysiological characterization of ectopic spontaneous discharge in axotomized and intact fibers upon nerve transection: a role in spontaneous pain? Pflugers Arch 2022; 474:387-396. [PMID: 35088129 DOI: 10.1007/s00424-021-02655-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 12/13/2021] [Accepted: 12/14/2021] [Indexed: 12/14/2022]
Abstract
Many patients experience positive symptoms after traumatic nerve injury. Despite the increasing number of experimental studies in models of peripheral neuropathy and the knowledge acquired, most of these patients lack an effective treatment for their chronic pain. One possible explanation might be that most of the preclinical studies focused on the development of mechanical or thermal allodynia/hyperalgesia, neglecting that most of the patients with peripheral neuropathies complain mostly about spontaneous forms of pains. Here, we summarize the aberrant electrophysiological behavior of peripheral nerve fibers recorded in experimental models, the underlying pathophysiological mechanisms, and their relationship with the symptoms reported by patients. Upon nerve section, axotomized but also intact fibers develop ectopic spontaneous activity. Most interestingly, a proportion of axotomized fibers might present receptive fields in the skin far beyond the site of damage, indicative of a functional cross talk between neuromatose and intact fibers. All these features can be linked with some of the symptoms that neuropathic patients experience. Furthermore, we spotlight the consequence of primary afferents with different patterns of spontaneous discharge on the neural code and its relationship with chronic pain states. With this article, readers will be able to understand the pathophysiological mechanisms that might underlie some of the symptoms that experience neuropathic patients, with a special focus on spontaneous pain.
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Affiliation(s)
- Carolina Roza
- Dpto. Biología de Sistemas, Edificio de Medicina Universidad de Alcalá, 28871, Alcalá de Henares, Madrid, Spain.
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Lei X, Zeng J, Yan Y, Liu X. Blockage of HCN Channels Inhibits the Function of P2X Receptors in Rat Dorsal Root Ganglion Neurons. Neurochem Res 2022; 47:1083-1096. [PMID: 35064517 DOI: 10.1007/s11064-021-03509-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 12/06/2021] [Accepted: 12/14/2021] [Indexed: 12/12/2022]
Abstract
Hyperpolarization-activated cyclic nucleotide-gated channels and purinergic P2X receptors play critical roles in the nerve injury-induced pain hypersensitivity. Both HCN channels and P2XR are expressed in dorsal root ganglia sensory neurons. However, it is not clear whether the expression and function of P2X2 and P2X3 receptors can be modulated by HCN channel activity. For this reason, in rats with chronic constriction injury of sciatic nerve, we evaluated the effect of intrathecal administration of HCN channel blocker ZD7288 on nociceptive behavior and the expression of P2X2 and P2X3 in rat DRG. The mechanical withdrawal threshold was measured to evaluate pain behavior in rats. The protein expression of P2X2 and P2X3 receptor in rat DRG was observed by using Western Blot. The level of cAMP in rat DRG was measured by ELISA. As a result, decreased MWT was observed in CCI rats on 1 d after surgery, and the allodynia was sustained throughout the experimental period. In addition, CCI rats presented increased expression of P2X2 and P2X3 receptor in the ipsilateral DRG at 7 d and 14 d after CCI operation. Intrathecal injection of ZD7288 significantly reversed CCI-induced mechanical hyperalgesia, and attenuated the increased expression of P2X2 and P2X3 receptor in rat DRG, which open up the possibility that the expression of P2X2 and P2X3 receptor in DRG is down-regulated by HCN channel blocker ZD7288 in CCI rats. Furthermore, the level of cAMP in rat DRG significantly increased after nerve injury. Intrathecal administration of ZD7288 attenuated the increase of cAMP in DRG caused by nerve injury. Subsequently, effects of HCN channel activity on ATP-induced current (IATP) in rat DRG neurons were explored by using whole-cell patch-clamp techniques. ATP (100 μM) elicited three types of currents (fast, slow and mixed IATP) in cultured DRG neurons. Pretreatment with ZD7288 concentration-dependently inhibited three types of ATP-activated currents. On the other hand, pretreatment with 8-Br-cAMP (a cell-permeable cAMP analog, also known as an activator of PKA) significantly increased the amplitude of fast, slow and mixed IATP in DRG neurons. The enhanced effect of 8-Br-cAMP on ATP-activated currents could be reversed by ZD7288. In a summary, our observations suggest that the opening of HCN channels could enhance the expression and function of P2X2 and P2X3 receptor via the cAMP-PKA signaling pathway. This may be important for pathophysiological events occurring within the DRG, for where it is implicated in nerve injury-induced pain hypersensitivity.
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Affiliation(s)
- Xiaolu Lei
- Key Laboratory of Brain Science, Zunyi Medical University, Zunyi, 563000, China
| | - Junwei Zeng
- Department of Physiology, Zunyi Medical University, No. 6, Xuefu west road, Zunyi, 563000, Guizhou province, China
| | - Yan Yan
- Key Laboratory of Brain Science, Zunyi Medical University, Zunyi, 563000, China
| | - Xiaohong Liu
- Department of Physiology, Zunyi Medical University, No. 6, Xuefu west road, Zunyi, 563000, Guizhou province, China.
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10
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Jansen LAR, Forster LA, Smith XL, Rubaharan M, Murphy AZ, Baro DJ. Changes in peripheral HCN2 channels during persistent inflammation. Channels (Austin) 2021; 15:165-179. [PMID: 33423595 PMCID: PMC7808421 DOI: 10.1080/19336950.2020.1870086] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 12/22/2020] [Accepted: 12/23/2020] [Indexed: 02/01/2023] Open
Abstract
Nociceptor sensitization following nerve injury or inflammation leads to chronic pain. An increase in the nociceptor hyperpolarization-activated current, Ih, is observed in many models of pathological pain. Pharmacological blockade of Ih prevents the mechanical and thermal hypersensitivity that occurs during pathological pain. Alterations in the Hyperpolarization-activated Cyclic Nucleotide-gated ion channel 2 (HCN2) mediate Ih-dependent thermal and mechanical hyperalgesia. Limited knowledge exists regarding the nature of these changes during chronic inflammatory pain. Modifications in HCN2 expression and post-translational SUMOylation have been observed in the Complete Freund's Adjuvant (CFA) model of chronic inflammatory pain. Intra-plantar injection of CFA into the rat hindpaw induces unilateral hyperalgesia that is sustained for up to 14 days following injection. The hindpaw is innervated by primary afferents in lumbar DRG, L4-6. Adjustments in HCN2 expression and SUMOylation have been well-documented for L5 DRG during the first 7 days of CFA-induced inflammation. Here, we examine bilateral L4 and L6 DRG at day 1 and day 3 post-CFA. Using L4 and L6 DRG cryosections, HCN2 expression and SUMOylation were measured with immunohistochemistry and proximity ligation assays, respectively. Our findings indicate that intra-plantar injection of CFA elicited a bilateral increase in HCN2 expression in L4 and L6 DRG at day 1, but not day 3, and enhanced HCN2 SUMOylation in ipsilateral L6 DRG at day 1 and day 3. Changes in HCN2 expression and SUMOylation were transient over this time course. Our study suggests that HCN2 is regulated by multiple mechanisms during CFA-induced inflammation.
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Affiliation(s)
- L-A. R. Jansen
- Department of Biology, Georgia State University, Atlanta, Georgia
| | - L. A. Forster
- Department of Biology, Georgia State University, Atlanta, Georgia
- Neuroscience Institute, Georgia State University, Atlanta, Georgia
| | - X. L. Smith
- Department of Biology, Georgia State University, Atlanta, Georgia
| | - M. Rubaharan
- Neuroscience Institute, Georgia State University, Atlanta, Georgia
| | - A. Z. Murphy
- Neuroscience Institute, Georgia State University, Atlanta, Georgia
| | - D. J. Baro
- Department of Biology, Georgia State University, Atlanta, Georgia
- Neuroscience Institute, Georgia State University, Atlanta, Georgia
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11
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Qian J, Tu H, Zhang D, Barksdale AN, Patel KP, Wadman MC, Li YL. Therapeutic effects of masitinib on abnormal mechanoreception in a mouse model of tourniquet-induced extremity ischemia-reperfusion. Eur J Pharmacol 2021; 911:174549. [PMID: 34619116 DOI: 10.1016/j.ejphar.2021.174549] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 09/01/2021] [Accepted: 09/30/2021] [Indexed: 11/18/2022]
Abstract
Tourniquets are widely used to stop extremity hemorrhage, but their use and subsequent release can result in nerve damage and degeneration, leading to neurological deficits. Increasing evidence has suggested a pivotal role of inflammation in nerve damage and abnormal mechanoreception. In this study, we investigated the therapeutic effects of masitinib (Mas), an anti-neuroinflammatory drug, on the mechanoreception of sensory neurons in a mouse model of tourniquet-induced hind paw ischemia-reperfusion (tourniquet/IR). C57BL/6 mice were subjected to 3 h of ischemia by placing a rubber band at the ankle joint and evaluated for subsequent reperfusion injury on day 1, 3, 7, 14, and 28 based on the experiments. Treatment with Mas (28 mg/kg/day, i.p.) began on the day of IR induction and lasted for 1, 3, 7, 14, or 28 days. Tourniquet/IR caused sensory nerve denervation in the skin of paw pads and abolished the hind paw mechanoreception to mechanical stimulation during the first 3 days of reperfusion. Sensory nerves gradually reinnervated in the skin of paw pads and allodynia began to appear on day 7. The maximum reaction occurred on day 14 and was maintained throughout the study period. Treatment with Mas mitigated nerve damage and improved hind paw mechanoreception to mechanical stimulation by decreasing the production of reactive oxygen species (ROS) during the early stages of tourniquet/IR. Mas also alleviated allodynia and decreased inflammatory cytokines (IL-1β and TNFα) in the skin of paw pads from days 7-28. Our data suggest that treatment with Mas significantly ameliorated paw numbness and allodynia in mouse hind paw tourniquet/IR.
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Affiliation(s)
- Junliang Qian
- Department of Emergency Medicine, University of Nebraska Medical Center, Omaha, NE, USA
| | - Huiyin Tu
- Department of Emergency Medicine, University of Nebraska Medical Center, Omaha, NE, USA
| | - Dongze Zhang
- Department of Emergency Medicine, University of Nebraska Medical Center, Omaha, NE, USA
| | - Aaron N Barksdale
- Department of Emergency Medicine, University of Nebraska Medical Center, Omaha, NE, USA
| | - Kaushik P Patel
- Department of Cellular & Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Michael C Wadman
- Department of Emergency Medicine, University of Nebraska Medical Center, Omaha, NE, USA
| | - Yu-Long Li
- Department of Emergency Medicine, University of Nebraska Medical Center, Omaha, NE, USA; Department of Cellular & Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, USA.
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12
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Bernard Healey SA, Scholtes I, Abrahams M, McNaughton PA, Menon DK, Lee MC. Role of hyperpolarization-activated cyclic nucleotide-gated ion channels in neuropathic pain: a proof-of-concept study of ivabradine in patients with chronic peripheral neuropathic pain. Pain Rep 2021; 6:e967. [PMID: 34712888 PMCID: PMC8547924 DOI: 10.1097/pr9.0000000000000967] [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: 06/29/2021] [Revised: 08/23/2021] [Accepted: 09/11/2021] [Indexed: 11/25/2022] Open
Abstract
Hyperpolarization-activated cyclic nucleotide-gated (HCN) channel receptors mediate neuropathic pain in preclinical models. Here, exploratory analysis reveals a dose-dependent reduction in pain with HCN blockade in patients with neuropathic pain. Introduction: Hyperpolarization-activated cyclic nucleotide-gated (HCN) ion channels mediate repetitive action potential firing in the heart and nervous system. The HCN2 isoform is expressed in nociceptors, and preclinical studies suggest a critical role in neuropathic pain. Ivabradine is a nonselective HCN blocker currently available for prescription for cardiac indications. Mouse data suggest that ivabradine in high concentrations is equianalgesic with gabapentin. We sought to translate these findings to patients with chronic peripheral neuropathic pain. Objectives: We sought to translate these findings to patients with chronic peripheral neuropathic pain. Methods: We adopted an open-label design, administering increasing doses of ivabradine to target a heart rate of 50 to 60 BPM, up to a maximum of 7.5 mg twice daily. All participants scored their pain on an 11-point numerical rating scale (NRS). Results: Seven (7) participants received the drug and completed the study. There was no significant treatment effect on the primary endpoint, the difference between the mean score at baseline and at maximum dosing (mean reduction = 0.878, 95% CI = −2.07 to 0.31, P = 0.1). Exploratory analysis using linear mixed models, however, revealed a highly significant correlation between ivabradine dose and pain scores (χ2(1) = 74.6, P < 0.001), with a reduction of 0.12 ± 0.01 (SEM) NRS points per milligram. The 2 participants with painful diabetic neuropathy responded particularly well. Conclusion: This suggests that ivabradine may be efficacious at higher doses, particularly in patients with diabetic neuropathic pain. Importantly, participants reported no adverse effects. These data suggest that ivabradine, a peripherally restricted drug (devoid of central nervous system side effects), is well tolerated in patients with chronic neuropathic pain. Ivabradine is now off-patent, and its analgesic potential merits further investigation in clinical trials.
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Affiliation(s)
| | - Ingrid Scholtes
- Division of Anaesthesia, University of Cambridge, Cambridge, United Kingdom
| | - Mark Abrahams
- Pain Service, Cambridge University Hospitals NHS Trust, Cambridge, United Kingdom
| | - Peter A McNaughton
- Wolfson Centre for Age-Related Diseases, King's College London, London, United Kingdom
| | - David K Menon
- Division of Anaesthesia, University of Cambridge, Cambridge, United Kingdom
| | - Michael C Lee
- Division of Anaesthesia, University of Cambridge, Cambridge, United Kingdom
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13
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Schmid AB, Fundaun J, Tampin B. [Entrapment neuropathies: a contemporary approach to pathophysiology, clinical assessment, and management : German version]. Schmerz 2021; 35:419-433. [PMID: 34505948 DOI: 10.1007/s00482-021-00584-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/16/2021] [Indexed: 10/20/2022]
Abstract
Entrapment neuropathies such as carpal tunnel syndrome, radiculopathies, or radicular pain are the most common peripheral neuropathies and also the most common cause for neuropathic pain. Despite their high prevalence, they often remain challenging to diagnose and manage in a clinical setting. Summarising the evidence from both preclinical and clinical studies, this review provides an update on the aetiology and pathophysiology of entrapment neuropathies. Potenzial mechanisms are put in perspective with clinical findings. The contemporary assessment is discussed and diagnostic pitfalls highlighted. The evidence for the noninvasive and surgical management of common entrapment neuropathies is summarised and future areas of research are identified.
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Affiliation(s)
- Annina B Schmid
- Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, Oxford University, West Wing Level 6, OX3 9DU, Oxford, Großbritannien.
| | - Joel Fundaun
- Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, Oxford University, West Wing Level 6, OX3 9DU, Oxford, Großbritannien.,High Country Physical Therapy, Laramie, WY, USA
| | - Brigitte Tampin
- Department of Physiotherapy, Sir Charles Gairdner Hospital, Perth, Westaustralien, Australien.,School of Physiotherapy and Exercise Science, Curtin University, Westaustralien, Australien.,Fakultät Wirtschafts- und Sozialwissenschaften, Hochschule Osnabrück, Osnabrück, Deutschland
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14
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Ma Y, Chen J, Yu D, Wei B, Jin H, Zeng J, Liu X. cAMP-PKA signaling is involved in regulation of spinal HCN channels function in diabetic neuropathic pain. Neurosci Lett 2021; 750:135763. [PMID: 33617945 DOI: 10.1016/j.neulet.2021.135763] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 02/07/2021] [Accepted: 02/16/2021] [Indexed: 12/23/2022]
Abstract
The cyclic adenosine monophosphate-protein kinase A (cAMP-PKA) signaling acts a pivotal part in hyperpolarization-activated cyclic nucleotide-gated (HCN) channels-mediated neuropathic and inflammatory pain. However, there has been no evidence of cAMP-PKA signaling is involved in regulation of spinal HCN channels function in the occurrence of diabetic neuropathic pain (DNP). The study aimed to elucidate the impact of HCN channels on neuropathic pain in a rat model of diabetes induced by streptozotocin, and whether cAMP-PKA signaling is involved in regulation of HCN channels function. In this report, we evaluated the effect of intrathecal administration of HCN channel blockers ZD7288, cAMP inhibitor SQ22536 and PKA inhibitor H-89 on nociceptive behavior in DNP rats. The mechanical withdrawal threshold (MWT) was measured to evaluate pain behavior in rats. Protein expression levels of HCN2, HCN4 channels and PKA in the spinal dorsal horn of rats were assessed. Furthermore, the levels of cAMP in rat spinal dorsal horn was analyzed. We discovered that DNP rats showed significant mechanical allodynia and are related to the increased HCN2 and HCN4 channels expression, enhanced cAMP production and elevated the expression of PKA protein in the spinal dorsal horn, which were attenuated by intrathecal ZD7288. Furthermore, intrathecal injection of SQ22536 and H-89 significantly reduced the HCN2 and HCN4 channels expression in the spinal dorsal horn of DNP rats. Our findings indicate that HCN channels of the spinal dorsal horn participate in the pathogenesis of allodynia in rats with DNP, which could be regulated by cAMP-PKA signaling. Therefore, HCN channels and cAMP-PKA signaling are potential targets for hyperalgesia treatment in DNP patients.
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Affiliation(s)
- Yanqiao Ma
- Department of Physiology, Zunyi Medical University, Zunyi, 563000, China
| | - Ji Chen
- School of Pharmacy, Qingdao University, Qingdao 266000, China
| | - Deqian Yu
- Department of Physiology, Zunyi Medical University, Zunyi, 563000, China
| | - Bangcong Wei
- Department of Physiology, Zunyi Medical University, Zunyi, 563000, China
| | - Huan Jin
- Department of Physiology, Zunyi Medical University, Zunyi, 563000, China
| | - Junwei Zeng
- Department of Physiology, Zunyi Medical University, Zunyi, 563000, China
| | - Xiaohong Liu
- Department of Physiology, Zunyi Medical University, Zunyi, 563000, China.
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15
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Santoro B, Shah MM. Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels as Drug Targets for Neurological Disorders. Annu Rev Pharmacol Toxicol 2020; 60:109-131. [PMID: 31914897 DOI: 10.1146/annurev-pharmtox-010919-023356] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The hyperpolarization-activated cyclic nucleotide-gated (HCN) channels are voltage-gated ion channels that critically modulate neuronal activity. Four HCN subunits (HCN1-4) have been cloned, each having a unique expression profile and distinctive effects on neuronal excitability within the brain. Consistent with this, the expression and function of these subunits are altered in diverse ways in neurological disorders. Here, we review current knowledge on the structure and distribution of the individual HCN channel isoforms, their effects on neuronal activity under physiological conditions, and how their expression and function are altered in neurological disorders, particularly epilepsy, neuropathic pain, and affective disorders. We discuss the suitability of HCN channels as therapeutic targets and how drugs might be strategically designed to specifically act on particular isoforms. We conclude that medicines that target individual HCN isoforms and/or their auxiliary subunit, TRIP8b, may provide valuable means of treating distinct neurological conditions.
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Affiliation(s)
- Bina Santoro
- Department of Neuroscience, Columbia University, New York, NY 10027, USA
| | - Mala M Shah
- Department of Pharmacology, School of Pharmacy, University College London, London WC1N 1AX, United Kingdom;
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16
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Hegazy N, Rezq S, Fahmy A. Mechanisms Involved in Superiority of Angiotensin Receptor Blockade over ACE Inhibition in Attenuating Neuropathic Pain Induced in Rats. Neurotherapeutics 2020; 17:1031-1047. [PMID: 32804335 PMCID: PMC7609714 DOI: 10.1007/s13311-020-00912-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Although previous reports described the beneficial role of angiotensin-converting enzyme inhibitors (ACE-Is) or AT1 receptor blockers (ARBs) in attenuating neuropathic pain (NP), no study has yet explored the exact underlying mechanisms, as well as the superiority of using centrally versus peripherally acting renin-angiotensin-aldosterone system (RAAS) drugs in NP. We investigated the effects of 14 days of treatment with centrally (telmisartan and ramipril) or peripherally (losartan and enalapril) acting ARBs and ACE-Is, respectively, in attenuating peripheral NP induced by sciatic nerve chronic constriction injury (CCI) in rats. We also compared these with the effects of pregabalin, the standard treatment for NP. Behavioral changes, inflammatory markers (NFкB, TNF-α, COX-2, PGE2, and bradykinin), oxidative stress markers (NADPH oxidase and catalase), STAT3 activation, levels of phosphorylated P38-MAPK, ACE, AT1 receptor (AT1R), and AT2 receptor (AT2R), as well as histopathological features, were assessed in the brainstem and sciatic nerve. CCI resulted in clear pain-related behavior along with increased levels of inflammatory and oxidative stress markers, and STAT3 activity, as well as increased levels of phosphorylated P38-MAPK, ACE, AT1R, and AT2R, along with worsened histopathological findings in both the brainstem and sciatic nerve. ARBs improved both animal behavior and all measured parameters in CCI rats and were more effective than ACE-Is. At the tested doses, centrally acting ARBs or ACE-Is were not superior to the peripherally acting drugs of the same category. These findings suggest that ARBs (centrally or peripherally acting) are an effective treatment modality for NP.
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Affiliation(s)
- Nora Hegazy
- Department of Pharmacology and Toxicology, School of Pharmacy, Zagazig University, Zagazig, 44519, Egypt
| | - Samar Rezq
- Department of Pharmacology and Toxicology, School of Pharmacy, Zagazig University, Zagazig, 44519, Egypt.
- Department of Cell and Molecular Biology, University of Mississippi Medical Center, 2500 North State Street, Jackson, 39216, MS, USA.
| | - Ahmed Fahmy
- Department of Pharmacology and Toxicology, School of Pharmacy, Zagazig University, Zagazig, 44519, Egypt
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17
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Schmid AB, Fundaun J, Tampin B. Entrapment neuropathies: a contemporary approach to pathophysiology, clinical assessment, and management. Pain Rep 2020; 5:e829. [PMID: 32766466 PMCID: PMC7382548 DOI: 10.1097/pr9.0000000000000829] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 05/04/2020] [Accepted: 05/30/2020] [Indexed: 12/18/2022] Open
Abstract
Entrapment neuropathies such as carpal tunnel syndrome, radiculopathies, or radicular pain are the most common peripheral neuropathies and also the most common cause for neuropathic pain. Despite their high prevalence, they often remain challenging to diagnose and manage in a clinical setting. Summarising the evidence from both preclinical and clinical studies, this review provides an update on the aetiology and pathophysiology of entrapment neuropathies. Potential mechanisms are put in perspective with clinical findings. The contemporary assessment is discussed and diagnostic pitfalls highlighted. The evidence for the noninvasive and surgical management of common entrapment neuropathies is summarised and future areas of research are identified.
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Affiliation(s)
- Annina B. Schmid
- Nuffield Department of Clinical Neurosciences, Oxford University, Oxford, United Kingdom
| | - Joel Fundaun
- Nuffield Department of Clinical Neurosciences, Oxford University, Oxford, United Kingdom
- High Country Physical Therapy, Laramie, WY, USA
| | - Brigitte Tampin
- Department of Physiotherapy, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia
- School of Physiotherapy and Exercise Science, Curtin University, Western Australia, Australia
- Faculty of Business Management and Social Sciences, Hochschule Osnabrück, University of Applied Sciences, Osnabrück, Germany
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18
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Selected Ionotropic Receptors and Voltage-Gated Ion Channels: More Functional Competence for Human Induced Pluripotent Stem Cell (iPSC)-Derived Nociceptors. Brain Sci 2020; 10:brainsci10060344. [PMID: 32503260 PMCID: PMC7348931 DOI: 10.3390/brainsci10060344] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 05/28/2020] [Accepted: 05/30/2020] [Indexed: 01/09/2023] Open
Abstract
Preclinical research using different rodent model systems has largely contributed to the scientific progress in the pain field, however, it suffers from interspecies differences, limited access to human models, and ethical concerns. Human induced pluripotent stem cells (iPSCs) offer major advantages over animal models, i.e., they retain the genome of the donor (patient), and thus allow donor-specific and cell-type specific research. Consequently, human iPSC-derived nociceptors (iDNs) offer intriguingly new possibilities for patient-specific, animal-free research. In the present study, we characterized iDNs based on the expression of well described nociceptive markers and ion channels, and we conducted a side-by-side comparison of iDNs with mouse sensory neurons. Specifically, immunofluorescence (IF) analyses with selected markers including early somatosensory transcription factors (BRN3A/ISL1/RUNX1), the low-affinity nerve growth factor receptor (p75), hyperpolarization-activated cyclic nucleotide-gated channels (HCN), as well as high voltage-gated calcium channels (VGCC) of the CaV2 type, calcium permeable TRPV1 channels, and ionotropic GABAA receptors, were used to address the characteristics of the iDN phenotype. We further combined IF analyses with microfluorimetric Ca2+ measurements to address the functionality of these ion channels in iDNs. Thus, we provide a detailed morphological and functional characterization of iDNs, thereby, underpinning their enormous potential as an animal-free alternative for human specific research in the pain field for unveiling pathophysiological mechanisms and for unbiased, disease-specific personalized drug development.
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19
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Zhao H, Gao XY, Liu ZH, Lin JW, Wang SP, Wang DX, Zhang YB. Effects of the transcription factor Olig1 on the differentiation and remyelination of oligodendrocyte precursor cells after focal cerebral ischemia in rats. Mol Med Rep 2019; 20:4603-4611. [PMID: 31702031 PMCID: PMC6797933 DOI: 10.3892/mmr.2019.10713] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2019] [Accepted: 07/22/2019] [Indexed: 12/28/2022] Open
Abstract
The differentiation and maturation of oligodendrocyte precursor cells (OPCs) is important for remyelination in the central nervous system. Nevertheless, this process is often limited and incomplete in ischemic injury. Oligodendrocyte transcription factor 1 (Olig1) is important for the maturation of OPCs and the repair of demyelinated lesions. However, how Olig1 modulates the development of OPCs or the remyelination associated with ischemic injury remains unclear. The present study aimed to examine alterations in OPCs, and the expression of myelin and Olig1, at different time-points after focal cerebral ischemia using immunohistochemistry and western blot techniques to elucidate the role of Olig1 in the maturation of OPCs and remyelination. The present results showed that the expression of Olig1 significantly decreased at 1 day after middle cerebral artery occlusion (MCAO) and returned to normal levels from day 3 to 28. Additionally, Olig1 was found to translocate into the nucleus following ischemia in the brain. The number of OPCs in the ischemic striatum significantly declined at days 1 and 3 following MCAO, and increased at days 7, 14 and 28 compared with the control. The expression of myelin basic protein, a marker of mature oligodendrocytes and myelin, gradually decreased from day 1 to 7 after ischemia and recovered at day 14 and 28; however, the levels were lower than those in the control group. The present results indicated that the restored normal level of Olig1 following ischemia may play an important role in the maturation of OPCs through its translocation into the nucleus, where it may promote the growth and development of myelin under pathological conditions. However, this endogenous recovery mechanism fails to fully repair the demyelinated lesion. The data of the present study may help clinicians understand the expression pattern of Olig1 and its potential role in endogenous remyelination after ischemia, which may have implications for the treatment of diseases that lead to demyelination.
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Affiliation(s)
- Hong Zhao
- Department of Neurology, Dalian Municipal Central Hospital, Dalian, Liaoning 116033, P.R. China
| | - Xiao-Yu Gao
- Department of Neurology, The Affiliated Yantai Yuhuangding Hospital of Qingdao University, Yantai, Shandong 264000, P.R. China
| | - Zan-Hua Liu
- Department of Neurology, Nanjing Gaochun People's Hospital, Nanjing, Jiangsu 211300, P.R. China
| | - Jian-Wen Lin
- Department of Neurology, Dalian Municipal Central Hospital, Dalian, Liaoning 116033, P.R. China
| | - Su-Ping Wang
- Department of Neurology, Dalian Municipal Central Hospital, Dalian, Liaoning 116033, P.R. China
| | - De-Xin Wang
- Department of Neurology, Beijing Friendship Hospital, Capital Medical University, Beijing 100050, P.R. China
| | - Yong-Bo Zhang
- Department of Neurology, Beijing Friendship Hospital, Capital Medical University, Beijing 100050, P.R. China
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20
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Ciotu CI, Tsantoulas C, Meents J, Lampert A, McMahon SB, Ludwig A, Fischer MJM. Noncanonical Ion Channel Behaviour in Pain. Int J Mol Sci 2019; 20:E4572. [PMID: 31540178 PMCID: PMC6770626 DOI: 10.3390/ijms20184572] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 09/09/2019] [Accepted: 09/12/2019] [Indexed: 12/19/2022] Open
Abstract
Ion channels contribute fundamental properties to cell membranes. Although highly diverse in conductivity, structure, location, and function, many of them can be regulated by common mechanisms, such as voltage or (de-)phosphorylation. Primarily considering ion channels involved in the nociceptive system, this review covers more novel and less known features. Accordingly, we outline noncanonical operation of voltage-gated sodium, potassium, transient receptor potential (TRP), and hyperpolarization-activated cyclic nucleotide (HCN)-gated channels. Noncanonical features discussed include properties as a memory for prior voltage and chemical exposure, alternative ion conduction pathways, cluster formation, and silent subunits. Complementary to this main focus, the intention is also to transfer knowledge between fields, which become inevitably more separate due to their size.
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Affiliation(s)
- Cosmin I Ciotu
- Center for Physiology and Pharmacology, Medical University of Vienna, 1090 Vienna, Austria
| | | | - Jannis Meents
- Institute of Physiology, University Hospital RWTH Aachen, 52074 Aachen, Germany
| | - Angelika Lampert
- Institute of Physiology, University Hospital RWTH Aachen, 52074 Aachen, Germany
| | - Stephen B McMahon
- Wolfson Centre for Age-Related Diseases, King's College London, London SE1 1UR, UK
| | - Andreas Ludwig
- Institute of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Michael J M Fischer
- Center for Physiology and Pharmacology, Medical University of Vienna, 1090 Vienna, Austria.
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21
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Liu Q, Chen W, Fan X, Wang J, Fu S, Cui S, Liao F, Cai J, Wang X, Huang Y, Su L, Zhong L, Yi M, Liu F, Wan Y. Upregulation of interleukin-6 on Cav3.2 T-type calcium channels in dorsal root ganglion neurons contributes to neuropathic pain in rats with spinal nerve ligation. Exp Neurol 2019; 317:226-243. [DOI: 10.1016/j.expneurol.2019.03.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2018] [Revised: 02/22/2019] [Accepted: 03/09/2019] [Indexed: 10/27/2022]
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22
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A randomised, double-blind, placebo-controlled crossover trial of the influence of the HCN channel blocker ivabradine in a healthy volunteer pain model: an enriched population trial. Pain 2019; 160:2554-2565. [DOI: 10.1097/j.pain.0000000000001638] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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23
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Li ZH, Cui D, Qiu CJ, Song XJ. Cyclic nucleotide signaling in sensory neuron hyperexcitability and chronic pain after nerve injury. NEUROBIOLOGY OF PAIN 2019; 6:100028. [PMID: 31223142 PMCID: PMC6565612 DOI: 10.1016/j.ynpai.2019.100028] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2018] [Revised: 03/06/2019] [Accepted: 03/07/2019] [Indexed: 11/08/2022]
Abstract
Activation of cAMP-PKA and cGMP-PKG pathways contributes to injury-induced sensory neuron hyperexcitability. Activation of cAMP and cGMP contributes to the development of bone cancer pain. PAR2 activation mediates injury-induced cAMP-dependent sensory neuron hyperexcitability.
The cyclic nucleotide signaling, including cAMP-PKA and cGMP-PKG pathways, has been well known to play critical roles in regulating cellular growth, metabolism and many other intracellular processes. In recent years, more and more studies have uncovered the roles of cAMP and cGMP in the nervous system. The cAMP and cGMP signaling mediates chronic pain induced by different forms of injury and stress. Here we summarize the roles of cAMP-PKA and cGMP-PKG signaling pathways in the pathogenesis of chronic pain after nerve injury. In addition, acute dissociation and chronic compression of the dorsal root ganglion (DRG) neurons, respectively, leads to neural hyperexcitability possibly through PAR2 activation-dependent activation of cAMP-PKA pathway. Clinically, radiotherapy can effectively alleviate bone cancer pain at least partly through inhibiting the cancer cell-induced activation of cAMP-PKA pathway. Roles of cyclic nucleotide signaling in neuropathic and inflammatory pain are also seen in many other animal models and are involved in many pro-nociceptive mechanisms including the activation of hyperpolarization-activated cyclic nucleotide (HCN)-modulated ion channels and the exchange proteins directly activated by cAMP (EPAC). Further understanding the roles of cAMP and cGMP signaling in the pathogenesis of chronic pain is theoretically significant and clinically valuable for treatment of chronic pain.
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Affiliation(s)
- Ze-Hua Li
- Department of Biology, SUSTech Center for Pain Medicine, and Medical School, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China.,Department of Anesthesiology and Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education of China), Peking University School of Oncology, Beijing Cancer Hospital & Institute, Beijing 100142, China
| | - Dong Cui
- Department of Biology, SUSTech Center for Pain Medicine, and Medical School, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China.,Department of Anesthesiology and Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education of China), Peking University School of Oncology, Beijing Cancer Hospital & Institute, Beijing 100142, China
| | - Cheng-Jie Qiu
- Department of Biology, SUSTech Center for Pain Medicine, and Medical School, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Xue-Jun Song
- Department of Biology, SUSTech Center for Pain Medicine, and Medical School, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China.,Department of Anesthesiology and Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education of China), Peking University School of Oncology, Beijing Cancer Hospital & Institute, Beijing 100142, China
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24
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Dexmedetomidine relieves neuropathic pain by inhibiting hyperpolarization-activated cyclic nucleotide-gated currents in dorsal root ganglia neurons. Neuroreport 2019; 29:1001-1006. [PMID: 29912028 DOI: 10.1097/wnr.0000000000001068] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
This study was designed to examine the effect and mechanism of dexmedetomidine (Dex) on neuropathic pain (NP). The NP model was established by performing chronic sciatic nerve constriction injury (CCI). Seven days after CCI surgery, the rats were injected intraperitoneally with Dex, ZD7288 (an HCN channel inhibitor), and saline, respectively. The paw withdrawal threshold to mechanical stimulation and the thermal withdrawal latency tests were performed. After administration, the L4, L5 dorsal root ganglia (DRG) neurons of rats were isolated. In addition, hyperpolarization-activated cyclic nucleotide-gated (HCN) channels subtype plasmids were transfected into human embryonic kidney (HEK)293 cells. Whole-cell clamp recordings were used to examine the properties of HCN currents (Ih) expressed in HEK293 cells and DRG neurons. After surgery, the paw withdrawal threshold to mechanical stimulation and thermal withdrawal latency were reduced, the HCN currents (Ih) amplitude of DRG neurons was increased, and the semiactivated voltage (V1/2) value was decreased in CCI rats (P<0.05). CCI rats treated with Dex or ZD7288 had reduced mechanical and thermal hyperalgesia. The Ih amplitude was lower and the V1/2 value was increased in DRG neurons in CCI rats treated with Dex or ZD7288 (P<0.05). In addition, Dex inhibited HCN1 and HCN2 currents in HEK293 cells; caused a decrease in maximal currents, an increase in the inhibition rate of Ih, and a negative shift in V1/2 (P<0.05). Taken together, our finding suggested that Dex alleviates NP and the effect is likely because of the inhibition of HCN currents.
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25
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He JT, Li XY, Zhao X, Liu X. Hyperpolarization-activated and cyclic nucleotide-gated channel proteins as emerging new targets in neuropathic pain. Rev Neurosci 2019; 30:639-649. [PMID: 30768426 DOI: 10.1515/revneuro-2018-0094] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Accepted: 10/26/2018] [Indexed: 01/14/2023]
Abstract
Abstract
Hyperpolarization-activated and cyclic nucleotide-gated (HCN) channels are activated during hyperpolarization, and there is an inward flow of current, which is termed as hyperpolarization-activated current, Ih. Initially, these channels were identified on the pacemaker cells of the heart. Nowadays, these are identified on different regions of the nervous system, including peripheral nerves, dorsal root ganglia, dorsal horns, and different parts of the brain. There are four different types of HCN channels (HCN1–HCN4); however, HCN1 and HCN2 are more prominent. A large number of studies have shown that peripheral nerve injury increases the amplitude of Ih current in the neurons of the spinal cord and the brain. Moreover, there is an increase in the expression of HCN1 and HCN2 protein channels in peripheral axons and the spinal cord and brain regions in experimental models of nerve injury. Studies have also documented the pain-attenuating actions of selective HCN inhibitors, such as ivabradine and ZD7288. Moreover, certain drugs with additional HCN-blocking activities have also shown pain-attenuating actions in different pain models. There have been few studies documenting the relationship of HCN channels with other mediators of pain. Nevertheless, it may be proposed that the HCN channel activity is modulated by endogenous opioids and cyclo-oxygenase-2, whereas the activation of these channels may modulate the actions of substance P and the expression of spinal N-methyl-D-aspartate receptor subunit 2B to modulate pain. The present review describes the role and mechanisms of HCN ion channels in the development of neuropathic pain.
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Affiliation(s)
- Jin-Ting He
- Department of Neurology , China-Japan Union Hospital, Jilin University , Changchun 130033, Jilin Province , China
| | - Xiao-Yan Li
- Department of Neurology , China-Japan Union Hospital, Jilin University , Changchun 130033, Jilin Province , China
| | - Xin Zhao
- Department of Paediatrics , The First Hospital of Jilin University , Changchun 130021, Jilin Province , China
| | - Xiaoliang Liu
- Cancer Center, The First Hospital of Jilin University , 126 Xiantai Street , Changchun 130033, Jilin Province , China
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26
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Joyce RL, Beyer NP, Vasilopoulos G, Woll KA, Hall AC, Eckenhoff RG, Barman DN, Warren JD, Tibbs GR, Goldstein PA. Alkylphenol inverse agonists of HCN1 gating: H-bond propensity, ring saturation and adduct geometry differentially determine efficacy and potency. Biochem Pharmacol 2019; 163:493-508. [PMID: 30768926 DOI: 10.1016/j.bcp.2019.02.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 02/11/2019] [Indexed: 10/27/2022]
Abstract
BACKGROUND AND PURPOSE In models of neuropathic pain, inhibition of HCN1 is anti-hyperalgesic. 2,6-di-iso-propyl phenol (propofol) and its non-anesthetic congener, 2,6-di-tert-butyl phenol, inhibit HCN1 channels by stabilizing closed state(s). EXPERIMENTAL APPROACH Using in vitro electrophysiology and kinetic modeling, we systematically explore the contribution of ligand architecture to alkylphenol-channel coupling. KEY RESULTS When corrected for changes in hydrophobicity (and propensity for intra-membrane partitioning), the decrease in potency upon 1-position substitution (NCO∼OH >> SH >>> F) mirrors the ligands' H-bond acceptor (NCO > OH > SH >>> F) but not donor profile (OH > SH >>> NCO∼F). H-bond elimination (OH to F) corresponds to a ΔΔG of ∼4.5 kCal mol-1 loss of potency with little or no disruption of efficacy. Substitution of compact alkyl groups (iso-propyl, tert-butyl) with shorter (ethyl, methyl) or more extended (sec-butyl) adducts disrupts both potency and efficacy. Ring saturation (with the obligate loss of both planarity and π electrons) primarily disrupts efficacy. CONCLUSIONS AND IMPLICATIONS A hydrophobicity-independent decrement in potency at higher volumes suggests the alkylbenzene site has a volume of ≥800 Å3. Within this, a relatively static (with respect to ligand) H-bond donor contributes to initial binding with little involvement in generation of coupling energy. The influence of π electrons/ring planarity and alkyl adducts on efficacy reveals these aspects of the ligand present towards a face of the channel that undergoes structural changes during opening. The site's characteristics suggest it is "druggable"; introduction of other adducts on the ring may generate higher potency inverse agonists.
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Affiliation(s)
| | | | | | - Kellie A Woll
- University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
| | - Adam C Hall
- Smith College, Northampton, MA, United States
| | - Roderic G Eckenhoff
- University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
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27
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Dini L, Del Lungo M, Resta F, Melchiorre M, Spinelli V, Di Cesare Mannelli L, Ghelardini C, Laurino A, Sartiani L, Coppini R, Mannaioni G, Cerbai E, Romanelli MN. Selective Blockade of HCN1/HCN2 Channels as a Potential Pharmacological Strategy Against Pain. Front Pharmacol 2018; 9:1252. [PMID: 30467478 PMCID: PMC6237106 DOI: 10.3389/fphar.2018.01252] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 10/15/2018] [Indexed: 12/25/2022] Open
Abstract
A prominent role of hyperpolarization-activated, cyclic nucleotide-gated (HCN) channels has been suggested based on their expression and (dys)function in dorsal root ganglion (DRG) neurons, being likely involved in peripheral nociception. Using HCN blockers as antinociceptive drugs is prevented by the widespread distribution of these channels. However, tissue-specific expression of HCN isoforms varies significantly, HCN1 and HCN2 being considered as major players in DRG excitability. We characterized the pharmacological effect of a novel compound, MEL55A, able to block selectively HCN1/HCN2 isoforms, on DRG neuron excitability in-vitro and for its antiallodynic properties in-vivo. HEK293 cells expressing HCN1, HCN2, or HCN4 isoforms were used to verify drug selectivity. The pharmacological profile of MEL55A was tested on mouse DRG neurons by patch-clamp recordings, and in-vivo in oxaliplatin-induced neuropathy by means of thermal hypersensitivity. Results were compared to the non-isoform-selective drug, ivabradine. MEL55A showed a marked preference toward HCN1 and HCN2 isoforms expressed in HEK293, with respect to HCN4. In cultured DRG, MEL55A reduced I h amplitude, both in basic conditions and after stimulation by forskolin, and cell excitability, its effect being quantitatively similar to that observed with ivabradine. MEL55A was able to relieve chemotherapy-induced neuropathic pain. In conclusion, selective blockade of HCN1/HCN2 channels, over HCN4 isoform, was able to modulate electrophysiological properties of DRG neurons similarly to that reported for classical I h blockers, ivabradine, resulting in a pain-relieving activity. The availability of small molecules with selectivity toward HCN channel isoforms involved in nociception might represent a safe and effective strategy against chronic pain.
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Affiliation(s)
- Leonardo Dini
- Department of Neurosciences, Psychology, Drug Research and Child Health (NeuroFarBa), University of Florence, Florence, Italy
| | - Martina Del Lungo
- Department of Neurosciences, Psychology, Drug Research and Child Health (NeuroFarBa), University of Florence, Florence, Italy
| | - Francesco Resta
- Department of Neurosciences, Psychology, Drug Research and Child Health (NeuroFarBa), University of Florence, Florence, Italy
| | - Michele Melchiorre
- Department of Neurosciences, Psychology, Drug Research and Child Health (NeuroFarBa), University of Florence, Florence, Italy
| | - Valentina Spinelli
- Department of Neurosciences, Psychology, Drug Research and Child Health (NeuroFarBa), University of Florence, Florence, Italy
| | - Lorenzo Di Cesare Mannelli
- Department of Neurosciences, Psychology, Drug Research and Child Health (NeuroFarBa), University of Florence, Florence, Italy
| | - Carla Ghelardini
- Department of Neurosciences, Psychology, Drug Research and Child Health (NeuroFarBa), University of Florence, Florence, Italy
| | - Annunziatina Laurino
- Department of Neurosciences, Psychology, Drug Research and Child Health (NeuroFarBa), University of Florence, Florence, Italy
| | - Laura Sartiani
- Department of Neurosciences, Psychology, Drug Research and Child Health (NeuroFarBa), University of Florence, Florence, Italy
| | - Raffaele Coppini
- Department of Neurosciences, Psychology, Drug Research and Child Health (NeuroFarBa), University of Florence, Florence, Italy
| | - Guido Mannaioni
- Department of Neurosciences, Psychology, Drug Research and Child Health (NeuroFarBa), University of Florence, Florence, Italy
| | - Elisabetta Cerbai
- Department of Neurosciences, Psychology, Drug Research and Child Health (NeuroFarBa), University of Florence, Florence, Italy
| | - Maria Novella Romanelli
- Department of Neurosciences, Psychology, Drug Research and Child Health (NeuroFarBa), University of Florence, Florence, Italy
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28
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Kang XJ, Chi YN, Chen W, Liu FY, Cui S, Liao FF, Cai J, Wan Y. Increased expression of Ca V3.2 T-type calcium channels in damaged DRG neurons contributes to neuropathic pain in rats with spared nerve injury. Mol Pain 2018; 14:1744806918765808. [PMID: 29592785 PMCID: PMC5888807 DOI: 10.1177/1744806918765808] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Ion channels are very important in the peripheral sensitization in neuropathic pain. Our present study aims to investigate the possible contribution of CaV3.2 T-type calcium channels in damaged dorsal root ganglion neurons in neuropathic pain. We established a neuropathic pain model of rats with spared nerve injury. In these model rats, it was easy to distinguish damaged dorsal root ganglion neurons (of tibial nerve and common peroneal nerve) from intact dorsal root ganglion neurons (of sural nerves). Our results showed that CaV3.2 protein expression increased in medium-sized neurons from the damaged dorsal root ganglions but not in the intact ones. With whole cell patch clamp recording technique, it was found that after-depolarizing amplitudes of the damaged medium-sized dorsal root ganglion neurons increased significantly at membrane potentials of −85 mV and −95 mV. These results indicate a functional up-regulation of CaV3.2 T-type calcium channels in the damaged medium-sized neurons after spared nerve injury. Behaviorally, blockade of CaV3.2 with antisense oligodeoxynucleotides could significantly reverse mechanical allodynia. These results suggest that CaV3.2 T-type calcium channels in damaged medium-sized dorsal root ganglion neurons might contribute to neuropathic pain after peripheral nerve injury.
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Affiliation(s)
- Xue-Jing Kang
- 1 Neuroscience Research Institute, Peking University, Beijing, China
| | - Ye-Nan Chi
- 1 Neuroscience Research Institute, Peking University, Beijing, China.,2 Department of Anesthesiology, Dongfang Hospital, Beijing University of Traditional Chinese Medicine, Beijing, China
| | - Wen Chen
- 1 Neuroscience Research Institute, Peking University, Beijing, China
| | - Feng-Yu Liu
- 1 Neuroscience Research Institute, Peking University, Beijing, China
| | - Shuang Cui
- 1 Neuroscience Research Institute, Peking University, Beijing, China
| | - Fei-Fei Liao
- 1 Neuroscience Research Institute, Peking University, Beijing, China
| | - Jie Cai
- 1 Neuroscience Research Institute, Peking University, Beijing, China
| | - You Wan
- 1 Neuroscience Research Institute, Peking University, Beijing, China.,3 Key Lab for Neuroscience, Ministry of Education/National Health and Family Planning Commission, Peking University, Beijing, China
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29
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Protein kinase A regulates inflammatory pain sensitization by modulating HCN2 channel activity in nociceptive sensory neurons. Pain 2018; 158:2012-2024. [PMID: 28767511 DOI: 10.1097/j.pain.0000000000001005] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Several studies implicated cyclic adenosine monophosphate (cAMP) as an important second messenger for regulating nociceptor sensitization, but downstream targets of this signaling pathway which contribute to neuronal plasticity are not well understood. We used a Cre/loxP-based strategy to disable the function of either HCN2 or PKA selectively in a subset of peripheral nociceptive neurons and analyzed the nociceptive responses in both transgenic lines. A near-complete lack of sensitization was observed in both mutant strains when peripheral inflammation was induced by an intradermal injection of 8br-cAMP. The lack of HCN2 as well as the inhibition of PKA eliminated the cAMP-mediated increase of calcium transients in dorsal root ganglion neurons. Facilitation of Ih via cAMP, a hallmark of the Ih current, was abolished in neurons without PKA activity. Collectively, these results show a significant contribution of both genes to inflammatory pain and suggest that PKA-dependent activation of HCN2 underlies cAMP-triggered neuronal sensitization.
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30
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Bernal L, Roza C. Hyperpolarization-activated channels shape temporal patterns of ectopic spontaneous discharge in C-nociceptors after peripheral nerve injury. Eur J Pain 2018; 22:1377-1387. [PMID: 29635758 DOI: 10.1002/ejp.1226] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/29/2018] [Indexed: 12/18/2022]
Abstract
BACKGROUND Neuropathic pain is thought to be mediated by aberrant impulses from sensitized primary afferents, and the temporal summation of the discharges might also influence nociceptive processing. Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels (Ih current) generate rhythmic activity in neurons within the central nervous system and contribute to nociceptors excitability in neuropathic pain. METHODS We searched for single fibres with ectopic spontaneous discharges from an in vitro preparation in mice containing a neuroma formed in a peripheral branch of the saphenous nerve together with the undamaged branches. RESULTS Both damaged (axotomized) and undamaged fibres (putative intact) developed ectopic spontaneous activity with different temporal spike trains: Clock-like, Irregular or Bursts. The Ih current blocker, ZD7288, significantly suppressed ectopic spontaneous discharges in nociceptive fibres (3/5 Aδ- and 24/31 C-units and 1 nonclassified) by 64%. Additionally, ZD7288 changed the spike patterns of 5/7 Clock-like and 3/4 Burst units to Irregular. Exogenous cAMP produced a significant ~65% increase in the ectopic firing in 5 Irregular fibres, which was restored by ZD7288. In six additional fibres (three Clock-like and three Irregular), exogenous cAMP had no further effect, but co-application with ZD7288 decreased their discharge by half. These units showed significant higher levels of discharges than the cAMP-sensitive ones. CONCLUSIONS Our data suggest that HCN channels modulate ectopic spontaneous firing in C-nociceptors and shape their temporal patterns of discharge which will, ultimately, modify the nociceptive message received and processed by second-order neurons. SIGNIFICANCE We show an involvement of HCN channels in the modulation of ectopic spontaneous discharges from C-nociceptors. This finding exposes a mechanism of nociceptive transmission enhancement and highlights the clinical relevance of peripheral HCN blockade for spontaneous pain relief during neuropathy.
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Affiliation(s)
- L Bernal
- Department of Biología de Sistemas, Universidad de Alcalá, Alcalá de Henares, Madrid, Spain
| | - C Roza
- Department of Biología de Sistemas, Universidad de Alcalá, Alcalá de Henares, Madrid, Spain
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31
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Chen W, Chi YN, Kang XJ, Liu QY, Zhang HL, Li ZH, Zhao ZF, Yang Y, Su L, Cai J, Liao FF, Yi M, Wan Y, Liu FY. Accumulation of Ca v3.2 T-type Calcium Channels in the Uninjured Sural Nerve Contributes to Neuropathic Pain in Rats with Spared Nerve Injury. Front Mol Neurosci 2018; 11:24. [PMID: 29472842 PMCID: PMC5809483 DOI: 10.3389/fnmol.2018.00024] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 01/17/2018] [Indexed: 11/13/2022] Open
Abstract
Injuries to peripheral nerve fibers induce neuropathic pain. But the involvement of adjacent uninjured fibers to pain is not fully understood. The present study aims to investigate the possible contribution of Cav3.2 T-type calcium channels in uninjured afferent nerve fibers to neuropathic pain in rats with spared nerve injury (SNI). Aβ-, Aδ- and C-fibers of the uninjured sural nerve were sensitized revealed by in vivo single-unit recording, which were accompanied by accumulation of Cav3.2 T-type calcium channel proteins shown by Western blotting. Application of mibefradil, a T-type calcium channel blocker, to sural nerve receptive fields increased mechanical thresholds of Aβ-, Aδ- and C-fibers, confirming the functional involvement of accumulated channels in the sural nerve in SNI rats. Finally, perineural application of mibefradil or TTA-P2 to the uninjured sural nerve alleviated mechanical allodynia in SNI rats. These results suggest that axonal accumulation of Cav3.2 T-type calcium channels plays an important role in the uninjured sural nerve sensitization and contributes to neuropathic pain.
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Affiliation(s)
- Wen Chen
- Neuroscience Research Institute, Peking University, Beijing, China.,Department of Neurobiology, School of Basic Medical Sciences, Peking University, Beijing, China.,Key Laboratory for Neuroscience, Ministry of Education/National Health and Family Planning Commission, Peking University, Beijing, China
| | - Ye-Nan Chi
- Neuroscience Research Institute, Peking University, Beijing, China.,Department of Anesthesiology, Dongfang Hospital, Beijing University of Chinese Medicine, Beijing, China
| | - Xue-Jing Kang
- Neuroscience Research Institute, Peking University, Beijing, China
| | - Qing-Ying Liu
- Neuroscience Research Institute, Peking University, Beijing, China
| | - Hao-Lin Zhang
- Neuroscience Research Institute, Peking University, Beijing, China
| | - Zhi-Hua Li
- Department of Human Anatomy, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Zi-Fang Zhao
- Neuroscience Research Institute, Peking University, Beijing, China
| | - Yin Yang
- Neuroscience Research Institute, Peking University, Beijing, China
| | - Li Su
- Neuroscience Research Institute, Peking University, Beijing, China.,Center of Medical and Health Analysis, Peking University, Beijing, China
| | - Jie Cai
- Neuroscience Research Institute, Peking University, Beijing, China
| | - Fei-Fei Liao
- Neuroscience Research Institute, Peking University, Beijing, China
| | - Ming Yi
- Neuroscience Research Institute, Peking University, Beijing, China
| | - You Wan
- Neuroscience Research Institute, Peking University, Beijing, China.,Department of Neurobiology, School of Basic Medical Sciences, Peking University, Beijing, China.,Key Laboratory for Neuroscience, Ministry of Education/National Health and Family Planning Commission, Peking University, Beijing, China
| | - Feng-Yu Liu
- Neuroscience Research Institute, Peking University, Beijing, China.,Department of Neurobiology, School of Basic Medical Sciences, Peking University, Beijing, China
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32
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Resta F, Micheli L, Laurino A, Spinelli V, Mello T, Sartiani L, Di Cesare Mannelli L, Cerbai E, Ghelardini C, Romanelli MN, Mannaioni G, Masi A. Selective HCN1 block as a strategy to control oxaliplatin-induced neuropathy. Neuropharmacology 2018; 131:403-413. [PMID: 29339292 DOI: 10.1016/j.neuropharm.2018.01.014] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 12/27/2017] [Accepted: 01/09/2018] [Indexed: 01/12/2023]
Abstract
Chemotherapy-Induced Peripheral Neuropathy (CIPN) is the most frequent adverse effect of pharmacological cancer treatments. The occurrence of neuropathy prevents the administration of fully-effective drug regimen, affects negatively the quality of life of patients, and may lead to therapy discontinuation. CIPN is currently treated with anticonvulsants, antidepressants, opioids and non-opioid analgesics, all of which are flawed by insufficient anti-hyperalgesic efficacy or addictive potential. Understandably, developing new drugs targeting CIPN-specific pathogenic mechanisms would dramatically improve efficacy and tolerability of anti-neuropathic therapies. Neuropathies are associated to aberrant excitability of DRG neurons due to the alteration in the expression or function of a variety of ion channels. In this regard, Hyperpolarization-activated Cyclic Nucleotide-gated (HCN) channels are overexpressed in inflammatory and neuropathic pain states, and HCN blockers have been shown to reduce neuronal excitability and to ameliorate painful states in animal models. However, HCN channels are critical in cardiac action potential, and HCN blockers used so far in pre-clinical models do not discriminate between cardiac and non-cardiac HCN isoforms. In this work, we show an HCN current gain of function in DRG neurons from oxaliplatin-treated rats. Biochemically, we observed a downregulation of HCN2 expression and an upregulation of the HCN regulatory beta-subunit MirP1. Finally, we report the efficacy of the selective HCN1 inhibitor MEL57A in reducing hyperalgesia and allodynia in oxaliplatin-treated rats without cardiac effects. In conclusion, this study strengthens the evidence for a disease-specific role of HCN1 in CIPN, and proposes HCN1-selective inhibitors as new-generation pain medications with the desired efficacy and safety profile.
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Affiliation(s)
- F Resta
- Department of Neuroscience, Psychology, Drug Research and Child Health - NEUROFARBA - Pharmacology and Toxicology Section, University of Florence, Florence, Italy.
| | - L Micheli
- Department of Neuroscience, Psychology, Drug Research and Child Health - NEUROFARBA - Pharmacology and Toxicology Section, University of Florence, Florence, Italy
| | - A Laurino
- Department of Neuroscience, Psychology, Drug Research and Child Health - NEUROFARBA - Pharmacology and Toxicology Section, University of Florence, Florence, Italy
| | - V Spinelli
- Department of Neuroscience, Psychology, Drug Research and Child Health - NEUROFARBA - Pharmacology and Toxicology Section, University of Florence, Florence, Italy
| | - T Mello
- Clinical Gastroenterology Laboratory, Department of Experimental and Clinical Biomedical Sciences, "Mario Serio" University of Florence, Florence, Italy
| | - L Sartiani
- Department of Neuroscience, Psychology, Drug Research and Child Health - NEUROFARBA - Pharmacology and Toxicology Section, University of Florence, Florence, Italy
| | - L Di Cesare Mannelli
- Department of Neuroscience, Psychology, Drug Research and Child Health - NEUROFARBA - Pharmacology and Toxicology Section, University of Florence, Florence, Italy
| | - E Cerbai
- Department of Neuroscience, Psychology, Drug Research and Child Health - NEUROFARBA - Pharmacology and Toxicology Section, University of Florence, Florence, Italy
| | - C Ghelardini
- Department of Neuroscience, Psychology, Drug Research and Child Health - NEUROFARBA - Pharmacology and Toxicology Section, University of Florence, Florence, Italy
| | - M N Romanelli
- Department of Neuroscience, Psychology, Drug Research and Child Health, Section of Pharmaceutical and Nutraceutical Sciences, University of Florence, via Ugo Schiff 6, Sesto Fiorentino, Italy
| | - G Mannaioni
- Department of Neuroscience, Psychology, Drug Research and Child Health - NEUROFARBA - Pharmacology and Toxicology Section, University of Florence, Florence, Italy
| | - A Masi
- Department of Neuroscience, Psychology, Drug Research and Child Health - NEUROFARBA - Pharmacology and Toxicology Section, University of Florence, Florence, Italy
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Sartiani L, Mannaioni G, Masi A, Novella Romanelli M, Cerbai E. The Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels: from Biophysics to Pharmacology of a Unique Family of Ion Channels. Pharmacol Rev 2017; 69:354-395. [PMID: 28878030 DOI: 10.1124/pr.117.014035] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 07/07/2017] [Indexed: 12/22/2022] Open
Abstract
Hyperpolarization-activated, cyclic nucleotide-gated (HCN) channels are important members of the voltage-gated pore loop channels family. They show unique features: they open at hyperpolarizing potential, carry a mixed Na/K current, and are regulated by cyclic nucleotides. Four different isoforms have been cloned (HCN1-4) that can assemble to form homo- or heterotetramers, characterized by different biophysical properties. These proteins are widely distributed throughout the body and involved in different physiologic processes, the most important being the generation of spontaneous electrical activity in the heart and the regulation of synaptic transmission in the brain. Their role in heart rate, neuronal pacemaking, dendritic integration, learning and memory, and visual and pain perceptions has been extensively studied; these channels have been found also in some peripheral tissues, where their functions still need to be fully elucidated. Genetic defects and altered expression of HCN channels are linked to several pathologies, which makes these proteins attractive targets for translational research; at the moment only one drug (ivabradine), which specifically blocks the hyperpolarization-activated current, is clinically available. This review discusses current knowledge about HCN channels, starting from their biophysical properties, origin, and developmental features, to (patho)physiologic role in different tissues and pharmacological modulation, ending with their present and future relevance as drug targets.
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Affiliation(s)
- Laura Sartiani
- Department of Neurosciences, Psychology, Drug Research, and Child Health, University of Florence, Firenze, Italy
| | - Guido Mannaioni
- Department of Neurosciences, Psychology, Drug Research, and Child Health, University of Florence, Firenze, Italy
| | - Alessio Masi
- Department of Neurosciences, Psychology, Drug Research, and Child Health, University of Florence, Firenze, Italy
| | - Maria Novella Romanelli
- Department of Neurosciences, Psychology, Drug Research, and Child Health, University of Florence, Firenze, Italy
| | - Elisabetta Cerbai
- Department of Neurosciences, Psychology, Drug Research, and Child Health, University of Florence, Firenze, Italy
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A novel intrinsic analgesic mechanism: the enhancement of the conduction failure along polymodal nociceptive C-fibers. Pain 2017; 157:2235-2247. [PMID: 27583680 PMCID: PMC5028159 DOI: 10.1097/j.pain.0000000000000632] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Supplemental Digital Content is Available in the Text. Conduction failure represents a prime target for modulating pain signals along C-fibers and might provide a new promising strategy to modulating pain with little side effects. Although conduction failure has been observed in nociceptive C-fibers, little is known regarding its significance or therapeutic potential. In a previous study, we demonstrated that C-fiber conduction failure, which is regarded as an intrinsic self-inhibition mechanism, was reduced in circumstances of painful diabetic neuropathy. In this study, we extend this finding in the complete Freund's adjuvant model of inflammatory pain and validate that the degree of conduction failure decreased and led to a greater amount of pain signals conveyed to the central nervous system. In complete Freund's adjuvant–injected animals, conduction failure occurred in a C-fiber-selective, activity-dependent manner and was associated with an increase in the rising slope of the C-fiber after-hyperpolarization potential. To target conduction failure in a therapeutic modality, we used ZD7288, an antagonist of hyperpolarization-activated, cyclic nucleotide–modulated channels which are activated by hyperpolarization and play a pivotal role in both inflammatory and neuropathic pain. ZD7288 promoted conduction failure by suppressing Ih as a mechanism to reduce the rising slope of the after-hyperpolarization potential. Moreover, perineuronal injection of ZD7288 inhibited abnormal mechanical allodynia and thermal hyperalgesia without affecting motor function or heart rate. Our data highlight the analgesic potential of local ZD7288 application and identify conduction failure as a novel target for analgesic therapeutic development.
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Khangura RK, Bali A, Kaur G, Singh N, Jaggi AS. Neuropathic pain attenuating effects of perampanel in an experimental model of chronic constriction injury in rats. Biomed Pharmacother 2017; 94:557-563. [DOI: 10.1016/j.biopha.2017.07.137] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Revised: 07/20/2017] [Accepted: 07/26/2017] [Indexed: 01/31/2023] Open
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Weerasinghe D, Menon P, Vucic S. Hyperpolarization-activated cyclic-nucleotide-gated channels potentially modulate axonal excitability at different thresholds. J Neurophysiol 2017; 118:3044-3050. [PMID: 28904107 DOI: 10.1152/jn.00576.2017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 09/06/2017] [Accepted: 09/12/2017] [Indexed: 11/22/2022] Open
Abstract
Hyperpolarization-activated cyclic-nucleotide-gated (HCN) channels mediate differences in sensory and motor axonal excitability at different thresholds in animal models. Importantly, HCN channels are responsible for voltage-gated inward rectifying (Ih) currents activated during hyperpolarization. The Ih currents exert a crucial role in determining the resting membrane potential and have been implicated in a variety of neurological disorders, including neuropathic pain. In humans, differences in biophysical properties of motor and sensory axons at different thresholds remain to be elucidated and could provide crucial pathophysiological insights in peripheral neurological diseases. Consequently, the aim of this study was to characterize sensory and motor axonal function at different threshold. Median nerve motor and sensory axonal excitability studies were undertaken in 15 healthy subjects (45 studies in total). Tracking targets were set to 20, 40, and 60% of maximum for sensory and motor axons. Hyperpolarizing threshold electrotonus (TEh) at 90-100 ms was significantly increased in lower threshold sensory axons times (F = 11.195, P < 0.001). In motor axons, the hyperpolarizing current/threshold (I/V) gradient was significantly increased in lower threshold axons (F = 3.191, P < 0.05). The minimum I/V gradient was increased in lower threshold motor and sensory axons. In conclusion, variation in the kinetics of HCN isoforms could account for the findings in motor and sensory axons. Importantly, assessing the function of HCN channels in sensory and motor axons of different thresholds may provide insights into the pathophysiological processes underlying peripheral neurological diseases in humans, particularly focusing on the role of HCN channels with the potential of identifying novel treatment targets.NEW & NOTEWORTHY Hyperpolarization-activated cyclic-nucleotide-gated (HCN) channels, which underlie inward rectifying currents (Ih), appear to mediate differences in sensory and motor axonal properties. Inward rectifying currents are increased in lower threshold motor and sensory axons, although different HCN channel isoforms appear to underlie these changes. While faster activating HCN channels seem to underlie Ih changes in sensory axons, slower activating HCN isoforms appear to be mediating the differences in Ih conductances in motor axons of different thresholds. The differences in HCN gating properties could explain the predilection for dysfunction of sensory and motor axons in specific neurological diseases.
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Affiliation(s)
| | - Parvathi Menon
- Department of Neurology, Westmead Hospital, Sydney, Australia; and.,Westmead Clinical School, The University of Sydney, Sydney, Australia
| | - Steve Vucic
- Department of Neurology, Westmead Hospital, Sydney, Australia; and .,Westmead Clinical School, The University of Sydney, Sydney, Australia
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Tabuena DR, Solis A, Geraldi K, Moffatt CA, Fuse M. Central neural alterations predominate in an insect model of nociceptive sensitization. J Comp Neurol 2017; 525:1176-1191. [PMID: 27650422 PMCID: PMC5258852 DOI: 10.1002/cne.24124] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Revised: 05/20/2016] [Accepted: 09/11/2016] [Indexed: 12/12/2022]
Abstract
Many organisms respond to noxious stimuli with defensive maneuvers. This is noted in the hornworm, Manduca sexta, as a defensive strike response. After tissue damage, organisms typically display sensitized responses to both noxious or normally innocuous stimuli. To further understand this phenomenon, we used novel in situ and in vitro preparations based on paired extracellular nerve recordings and videography to identify central and peripheral nerves responsible for nociception and sensitization of the defensive behavior in M. sexta. In addition, we used the in vivo defensive strike response threshold assayed with von Frey filaments to examine the roles that N-methyl-D-aspartate receptor (NMDAR) and hyperpolarization-activated, cyclic nucleotide-gated (HCN) channels play in this nociceptive sensitization using the inhibitors MK-801 and AP5 (NMDAR), and ivabradine and ZD7288 (HCN). Using our new preparations, we found that afferent activity evoked by noxious pinch in these preparations was conveyed to central ganglia by axons in the anterior- and lateral-dorsal nerve branches, and that sensitization induced by tissue damage was mediated centrally. Furthermore, sensitization was blocked by all inhibitors tested except the inactive isomer L-AP5, and reversed by ivabradine both in vivo and in vitro. Our findings suggest that M. sexta's sensitization occurs through central signal amplification. Due to the relatively natural sensitization method and conserved molecular actions, we suggest that M. sexta may be a valuable model for studying the electrophysiological properties of nociceptive sensitization and potentially related conditions such as allodynia and hyperalgesia in a comparative setting that offers unique experimental advantages. J. Comp. Neurol. 525:1176-1191, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Dennis R Tabuena
- San Francisco State University, Dept. Biology. 1600 Holloway Avenue, San Francisco, CA 94132
| | - Allan Solis
- City College of San Francisco, 50 Phelan Ave, San Francisco, CA 94112
| | - Ken Geraldi
- San Francisco State University, Dept. Biology. 1600 Holloway Avenue, San Francisco, CA 94132
| | - Christopher A Moffatt
- San Francisco State University, Dept. Biology. 1600 Holloway Avenue, San Francisco, CA 94132
| | - Megumi Fuse
- San Francisco State University, Dept. Biology. 1600 Holloway Avenue, San Francisco, CA 94132
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Sun W, Yang F, Wang Y, Fu H, Yang Y, Li CL, Wang XL, Lin Q, Chen J. Contribution of large-sized primary sensory neuronal sensitization to mechanical allodynia by upregulation of hyperpolarization-activated cyclic nucleotide gated channels via cyclooxygenase 1 cascade. Neuropharmacology 2016; 113:217-230. [PMID: 27743933 DOI: 10.1016/j.neuropharm.2016.10.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 10/08/2016] [Accepted: 10/11/2016] [Indexed: 11/18/2022]
Abstract
Under physiological state, small- and medium-sized dorsal root ganglia (DRG) neurons are believed to mediate nociceptive behavioral responses to painful stimuli. However, recently it has been found that a number of large-sized neurons are also involved in nociceptive transmission under neuropathic conditions. Nonetheless, the underlying mechanisms that large-sized DRG neurons mediate nociception are poorly understood. In the present study, the role of large-sized neurons in bee venom (BV)-induced mechanical allodynia and the underlying mechanisms were investigated. Behaviorally, it was found that mechanical allodynia was still evoked by BV injection in rats in which the transient receptor potential vanilloid 1-positive DRG neurons were chemically deleted. Electrophysiologically, in vitro patch clamp recordings of large-sized neurons showed hyperexcitability in these neurons. Interestingly, the firing pattern of these neurons was changed from phasic to tonic under BV-inflamed state. It has been suggested that hyperpolarization-activated cyclic nucleotide gated channels (HCN) expressed in large-sized DRG neurons contribute importantly to repeatedly firing. So we examined the roles of HCNs in BV-induced mechanical allodynia. Consistent with the overexpression of HCN1/2 detected by immunofluorescence, HCNs-mediated hyperpolarization activated cation current (Ih) was significantly increased in the BV treated samples. Pharmacological experiments demonstrated that the hyperexcitability and upregulation of Ih in large-sized neurons were mediated by cyclooxygenase-1 (COX-1)-prostaglandin E2 pathway. This is evident by the fact that the COX-1 inhibitor significantly attenuated the BV-induced mechanical allodynia. These results suggest that BV can excite the large-sized DRG neurons at least in part by increasing Ih through activation of COX-1.
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Affiliation(s)
- Wei Sun
- Institute for Biomedical Sciences of Pain, Tangdu Hospital, The Fourth Military Medical University, Xi'an 710038, PR China; Key Laboratory of Brain Stress and Behavior, PLA, Xi'an 710038, PR China
| | - Fei Yang
- Institute for Biomedical Sciences of Pain, Tangdu Hospital, The Fourth Military Medical University, Xi'an 710038, PR China; Key Laboratory of Brain Stress and Behavior, PLA, Xi'an 710038, PR China
| | - Yan Wang
- Institute for Biomedical Sciences of Pain, Tangdu Hospital, The Fourth Military Medical University, Xi'an 710038, PR China; Key Laboratory of Brain Stress and Behavior, PLA, Xi'an 710038, PR China
| | - Han Fu
- Institute for Biomedical Sciences of Pain, Tangdu Hospital, The Fourth Military Medical University, Xi'an 710038, PR China; Key Laboratory of Brain Stress and Behavior, PLA, Xi'an 710038, PR China
| | - Yan Yang
- Institute for Biomedical Sciences of Pain, Tangdu Hospital, The Fourth Military Medical University, Xi'an 710038, PR China; Key Laboratory of Brain Stress and Behavior, PLA, Xi'an 710038, PR China
| | - Chun-Li Li
- Institute for Biomedical Sciences of Pain, Tangdu Hospital, The Fourth Military Medical University, Xi'an 710038, PR China; Key Laboratory of Brain Stress and Behavior, PLA, Xi'an 710038, PR China
| | - Xiao-Liang Wang
- Institute for Biomedical Sciences of Pain, Tangdu Hospital, The Fourth Military Medical University, Xi'an 710038, PR China; Key Laboratory of Brain Stress and Behavior, PLA, Xi'an 710038, PR China
| | - Qing Lin
- Department of Psychology, College of Science, The University of Texas at Arlington, Arlington, TX 76019, USA.
| | - Jun Chen
- Institute for Biomedical Sciences of Pain, Tangdu Hospital, The Fourth Military Medical University, Xi'an 710038, PR China; Key Laboratory of Brain Stress and Behavior, PLA, Xi'an 710038, PR China; Beijing Institute for Brain Disorders, Beijing 100069, PR China.
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HCN2 ion channels: basic science opens up possibilities for therapeutic intervention in neuropathic pain. Biochem J 2016; 473:2717-36. [DOI: 10.1042/bcj20160287] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Accepted: 05/18/2016] [Indexed: 01/22/2023]
Abstract
Nociception — the ability to detect painful stimuli — is an invaluable sense that warns against present or imminent damage. In patients with chronic pain, however, this warning signal persists in the absence of any genuine threat and affects all aspects of everyday life. Neuropathic pain, a form of chronic pain caused by damage to sensory nerves themselves, is dishearteningly refractory to drugs that may work in other types of pain and is a major unmet medical need begging for novel analgesics. Hyperpolarisation-activated cyclic nucleotide (HCN)-modulated ion channels are best known for their fundamental pacemaker role in the heart; here, we review data demonstrating that the HCN2 isoform acts in an analogous way as a ‘pacemaker for pain’, in that its activity in nociceptive neurons is critical for the maintenance of electrical activity and for the sensation of chronic pain in pathological pain states. Pharmacological block or genetic deletion of HCN2 in sensory neurons provides robust pain relief in a variety of animal models of inflammatory and neuropathic pain, without any effect on normal sensation of acute pain. We discuss the implications of these findings for our understanding of neuropathic pain pathogenesis, and we outline possible future opportunities for the development of efficacious and safe pharmacotherapies in a range of chronic pain syndromes.
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Hu T, Liu N, Lv M, Ma L, Peng H, Peng S, Liu T. Lidocaine Inhibits HCN Currents in Rat Spinal Substantia Gelatinosa Neurons. Anesth Analg 2016; 122:1048-59. [PMID: 26756913 PMCID: PMC4791316 DOI: 10.1213/ane.0000000000001140] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Lidocaine, which blocks voltage-gated sodium channels, is widely used in surgical anesthesia and pain management. Recently, it has been proposed that the hyperpolarization-activated cyclic nucleotide (HCN) channel is one of the other novel targets of lidocaine. Substantia gelatinosa in the spinal dorsal horn, which plays key roles in modulating nociceptive information from primary afferents, comprises heterogeneous interneurons that can be electrophysiologically categorized by firing pattern. Our previous study demonstrated that a substantial proportion of substantia gelatinosa neurons reveal the presence of HCN current (Ih); however, the roles of lidocaine and HCN channel expression in different types of substantia gelatinosa neurons remain unclear. METHODS By using the whole-cell patch-clamp technique, we investigated the effect of lidocaine on Ih in rat substantia gelatinosa neurons of acute dissociated spinal cord slices. RESULTS We found that lidocaine rapidly decreased the peak Ih amplitude with an IC50 of 80 μM. The inhibition rate on Ih was not significantly different with a second application of lidocaine in the same neuron. Tetrodotoxin, a sodium channel blocker, did not affect lidocaine's effect on Ih. In addition, lidocaine shifted the half-activation potential of Ih from -109.7 to -114.9 mV and slowed activation. Moreover, the reversal potential of Ih was shifted by -7.5 mV by lidocaine. In the current clamp, lidocaine decreased the resting membrane potential, increased membrane resistance, delayed rebound depolarization latency, and reduced the rebound spike frequency. We further found that approximately 58% of substantia gelatinosa neurons examined expressed Ih, in which most of them were tonically firing. CONCLUSIONS Our studies demonstrate that lidocaine strongly inhibits Ih in a reversible and concentration-dependent manner in substantia gelatinosa neurons, independent of tetrodotoxin-sensitive sodium channels. Thus, our study provides new insight into the mechanism underlying the central analgesic effect of the systemic administration of lidocaine.
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Affiliation(s)
- Tao Hu
- From the Departments of *Pediatrics and †Anesthesiology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, People's Republic of China; and ‡Center for Laboratory Medicine, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, People's Republic of China
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Tibbs GR, Posson DJ, Goldstein PA. Voltage-Gated Ion Channels in the PNS: Novel Therapies for Neuropathic Pain? Trends Pharmacol Sci 2016; 37:522-542. [DOI: 10.1016/j.tips.2016.05.002] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Revised: 03/24/2016] [Accepted: 05/03/2016] [Indexed: 12/19/2022]
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McGovern AE, Robusto J, Rakoczy J, Simmons DG, Phipps S, Mazzone SB. The effect of hyperpolarization-activated cyclic nucleotide-gated ion channel inhibitors on the vagal control of guinea pig airway smooth muscle tone. Br J Pharmacol 2016; 171:3633-50. [PMID: 24762027 DOI: 10.1111/bph.12745] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Revised: 02/10/2014] [Accepted: 02/14/2014] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND AND PURPOSE Subtypes of the hyperpolarization-activated cyclic nucleotide-gated (HCN) family of cation channels are widely expressed on nerves and smooth muscle cells in many organ systems, where they serve to regulate membrane excitability. Here we have assessed whether HCN channel inhibitors alter the function of airway smooth muscle or the neurons that regulate airway smooth muscle tone. EXPERIMENTAL APPROACH The effects of the HCN channel inhibitors ZD7288, zatebradine and Cs(+) were assessed on agonist and nerve stimulation-evoked changes in guinea pig airway smooth muscle tone using tracheal strips in vitro, an innervated tracheal tube preparation ex vivo or in anaesthetized mechanically ventilated guinea pigs in vivo. HCN channel expression in airway nerves was assessed using immunohistochemistry, PCR and in situ hybridization. KEY RESULTS HCN channel inhibition did not alter airway smooth muscle reactivity in vitro to exogenously administered smooth muscle spasmogens, but significantly potentiated smooth muscle contraction evoked by the sensory nerve stimulant capsaicin and electrical field stimulation of parasympathetic cholinergic postganglionic neurons. Sensory nerve hyperresponsiveness was also evident in in vivo following HCN channel blockade. Cs(+) , but not ZD7288, potentiated preganglionic nerve-dependent airway contractions and over time induced autorhythmic preganglionic nerve activity, which was not mimicked by inhibitors of potassium channels. HCN channel expression was most evident in vagal sensory ganglia and airway nerve fibres. CONCLUSIONS AND IMPLICATIONS HCN channel inhibitors had a previously unrecognized effect on the neural regulation of airway smooth muscle tone, which may have implications for some patients receiving HCN channel inhibitors for therapeutic purposes.
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Affiliation(s)
- Alice E McGovern
- School of Biomedical Sciences, University of Queensland, St Lucia, Qld, Australia
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Cordeiro Matos S, Zhang Z, Séguéla P. Peripheral Neuropathy Induces HCN Channel Dysfunction in Pyramidal Neurons of the Medial Prefrontal Cortex. J Neurosci 2015; 35:13244-56. [PMID: 26400952 PMCID: PMC6605438 DOI: 10.1523/jneurosci.0799-15.2015] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Revised: 08/21/2015] [Accepted: 08/22/2015] [Indexed: 01/28/2023] Open
Abstract
Neuropathic pain is a debilitating condition for which the development of effective treatments has been limited by an incomplete understanding of its molecular basis. The cationic current Ih mediated by hyperpolarization-activated cyclic nucleotide-gated (HCN) channels plays an important role in pain by facilitating ectopic firing and hyperexcitability in DRG neurons, however little is known regarding the role of Ih in supraspinal pain pathways. The medial prefrontal cortex (mPFC), which is reported to be involved in the affective aspects of pain, exhibits high HCN channel expression. Using the spared nerve injury (SNI) model of neuropathic pain in Long-Evans rats and patch-clamp recordings in layer II/III pyramidal neurons of the contralateral mPFC, we observed a hyperpolarizing shift in the voltage-dependent activation of Ih in SNI neurons, whereas maximal Ih remained unchanged. Accordingly, SNI mPFC pyramidal neurons exhibited increased input resistance and excitability, as well as facilitated glutamatergic mGluR5-mediated persistent firing, compared with sham neurons. Moreover, intracellular application of bromo-cAMP abolished the hyperpolarizing shift in the voltage-dependent activation of Ih observed in SNI neurons, whereas protein kinase A (PKA) inhibition further promoted this shift in both SNI and sham neurons. Behaviorally, acute HCN channel blockade by local injection of ZD7288 in the mPFC of SNI rats induced a decrease in cold allodynia. These findings suggest that changes in the cAMP/PKA axis in mPFC neurons underlie alterations to HCN channel function, which can influence descending inhibition of pain pathways in neuropathic conditions. Significance statement: Recent studies investigating the role of the medial prefrontal cortex (mPFC) in neuropathic pain have led to an increased awareness of how affective and cognitive factors can influence pain perception. It is therefore imperative that we advance our understanding of the involvement of supraspinal pain pathways. Our electrophysiological and behavioral results support an important role for hyperpolarization-activated cyclic nucleotide-gated channels and the cAMP/protein kinase A signaling axis in promoting hyperexcitability and persistent firing in pyramidal neurons of the mPFC in neuropathic animals. These findings offer novel insights, with potential therapeutic implications, into pathophysiological mechanisms underlying the abnormal contribution of layer II/III prefrontal pyramidal neurons to chronic pain states.
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Affiliation(s)
- Steven Cordeiro Matos
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, Alan Edwards Centre for Research on Pain, McGill University, Montreal, Quebec H3A 2B4, Canada
| | - Zizhen Zhang
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, Alan Edwards Centre for Research on Pain, McGill University, Montreal, Quebec H3A 2B4, Canada
| | - Philippe Séguéla
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, Alan Edwards Centre for Research on Pain, McGill University, Montreal, Quebec H3A 2B4, Canada
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Smith T, Al Otaibi M, Sathish J, Djouhri L. Increased expression of HCN2 channel protein in L4 dorsal root ganglion neurons following axotomy of L5- and inflammation of L4-spinal nerves in rats. Neuroscience 2015; 295:90-102. [DOI: 10.1016/j.neuroscience.2015.03.041] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Revised: 02/28/2015] [Accepted: 03/19/2015] [Indexed: 12/31/2022]
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Liu Y, Feng Y, Zhang T. Pulsed Radiofrequency Treatment Enhances Dorsal Root Ganglion Expression of Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels in a Rat Model of Neuropathic Pain. J Mol Neurosci 2015; 57:97-105. [PMID: 26018936 DOI: 10.1007/s12031-015-0582-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Accepted: 05/18/2015] [Indexed: 12/27/2022]
Abstract
Pulsed radiofrequency (PRF) treatment is a minimally invasive technique with multiple therapeutic applications. Hyperpolarization-activated cyclic nucleotide-gated (HCN) channel mediating Ih may regulate neuropathic pain signaling. This study aimed to determine whether PRF suppresses neuropathic pain by altering HCN channel expression in dorsal root ganglion (DRG) neurons. Male Sprague Dawley rats with sciatic nerve chronic constriction injury (CCI) were randomly assigned to PRF (n = 60) and sham control (n = 60) groups, respectively. On postoperative day 7 (D07), PRF or sham treatment was delivered to the proximal sciatic nerve for 8 min. Behavioral tests were performed before surgery (D0), on D07, and on D1, D7, and D14 after PRF or sham treatment. HCN1 and HCN2 expression levels in the DRG were examined by immunohistochemistry and Western blot. The results showed that thermal hyperalgesia, mechano-allodynia, and mechano-hyperalgesia were lower, and DRG expression levels of HCN1 and HCN2 higher, in the PRF group compared with sham control animals (all P < 0.05 at D14). In conclusion, PRF can upregulate HCN channel expression in the DRG of rats with sciatic nerve CCI. How this regulation of Ih in nociceptive afferents contributes to the suppression of neuropathic pain by PRF remains to be determined.
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Affiliation(s)
- Yiming Liu
- Pain medicine department, Peking University People's Hospital, No. 11, Xizhimen South Street, Xicheng District, Beijing, 100044, China
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Inhibition of Hyperpolarization-Activated Cation Current in Medium-Sized DRG Neurons Contributed to the Antiallodynic Effect of Methylcobalamin in the Rat of a Chronic Compression of the DRG. Neural Plast 2015; 2015:197392. [PMID: 26101670 PMCID: PMC4460234 DOI: 10.1155/2015/197392] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Revised: 03/23/2015] [Accepted: 03/23/2015] [Indexed: 02/05/2023] Open
Abstract
Recently several lines of evidence demonstrated that methylcobalamin (MeCbl) might have potential analgesic effect in experimental and clinical studies. However, it was reported that MeCbl had no effect on treating lumbar spinal stenosis induced pain. Thus, the effects of short-term and long-term administration of MeCbl were examined in the chronic compression of dorsal root ganglion (CCD) model. We found that mechanical allodynia was significantly inhibited by a continuous application of high dose and a single treatment of a super high dose of MeCbl. Little is known about mechanisms underlying the analgesia of MeCbl. We examined the effect of MeCbl on the spontaneous activity (SA), the excitability, and hyperpolarization-activated nonselective cation ion current in compressed medium-sized dorsal root ganglion (DRG) neurons using extracellular single fiber recording in vivo and whole-cell patch clamp in vitro. We found that MeCbl significantly inhibited the SA of A-type sensory neurons in a dose-dependent manner and inhibited the excitability of medium-sized DRG neurons. In addition, MeCbl also decreased Ih current density in injured medium-sized DRG neurons. Our results proved that MeCbl might exert an analgesic effect through the inhibition Ih current and then might inhibit the hyperexcitability of primary sensory neurons under neuropathic pain state.
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Hyperpolarization-activated cyclic nucleotide-gated channels may contribute to regional anesthetic effects of lidocaine. Anesthesiology 2015; 122:606-18. [PMID: 25485469 DOI: 10.1097/aln.0000000000000557] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND Local anesthetics (e.g., lidocaine) have been found to inhibit hyperpolarization-activated cyclic nucleotide-gated (HCN) channels besides sodium channels. However, the exact role of HCN channels in regional anesthesia in vivo is still elusive. METHODS Sciatic nerve block and intrathecal anesthesia were performed using lidocaine in wild-type and HCN1 channel knockout (HCN1) mice. EC50 of lidocaine and durations of 1% lidocaine were determined. In electrophysiologic recordings, effects of lidocaine on HCN channel currents, voltage-gated sodium channel currents, and neural membrane properties were recorded on dorsal root ganglia neurons. RESULTS In both sciatic nerve block and intrathecal anesthesia, EC50 of lidocaine for tactile sensory blockade (2 g von Frey fiber) was significantly increased in HCN1 mice, whereas EC50 of lidocaine for pinprick blockade was unaffected. Durations of 1% lidocaine were significantly shorter in HCN1 mice for both sciatic nerve block and intrathecal anesthesia (n = 10). ZD7288 (HCN blocker) could significantly prolong durations of 1% lidocaine including pinprick blockade in sciatic nerve block (n = 10). Forskolin (raising cyclic adenosine monophosphate to enhance HCN2) could significantly shorten duration of pinprick blockade of 1% lidocaine in sciatic nerve block (n = 10). In electrophysiologic recordings, lidocaine could nonselectively inhibit HCN channel and sodium channel currents both in large and in small dorsal root ganglia neurons (n = 5 to 6). Meanwhile, lidocaine caused neural membrane hyperpolarization and increased input resistance of dorsal root ganglia neurons but not in large dorsal root ganglia neurons from HCN1 mice (n = 5-7). CONCLUSIONS These data indicate that HCN channels may contribute to regional anesthetic effects of lidocaine. By inhibiting HCN channels, lidocaine could alter membrane properties of neurons.
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Shp-1 dephosphorylates TRPV1 in dorsal root ganglion neurons and alleviates CFA-induced inflammatory pain in rats. Pain 2015; 156:597-608. [DOI: 10.1097/01.j.pain.0000460351.30707.c4] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Herrmann S, Schnorr S, Ludwig A. HCN channels--modulators of cardiac and neuronal excitability. Int J Mol Sci 2015; 16:1429-47. [PMID: 25580535 PMCID: PMC4307311 DOI: 10.3390/ijms16011429] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Accepted: 12/31/2014] [Indexed: 01/06/2023] Open
Abstract
Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels comprise a family of cation channels activated by hyperpolarized membrane potentials and stimulated by intracellular cyclic nucleotides. The four members of this family, HCN1-4, show distinct biophysical properties which are most evident in the kinetics of activation and deactivation, the sensitivity towards cyclic nucleotides and the modulation by tyrosine phosphorylation. The four isoforms are differentially expressed in various excitable tissues. This review will mainly focus on recent insights into the functional role of the channels apart from their classic role as pacemakers. The importance of HCN channels in the cardiac ventricle and ventricular hypertrophy will be discussed. In addition, their functional significance in the peripheral nervous system and nociception will be examined. The data, which are mainly derived from studies using transgenic mice, suggest that HCN channels contribute significantly to cellular excitability in these tissues. Remarkably, the impact of the channels is clearly more pronounced in pathophysiological states including ventricular hypertrophy as well as neural inflammation and neuropathy suggesting that HCN channels may constitute promising drug targets in the treatment of these conditions. This perspective as well as the current therapeutic use of HCN blockers will also be addressed.
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Affiliation(s)
- Stefan Herrmann
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany.
| | - Sabine Schnorr
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany.
| | - Andreas Ludwig
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany.
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Abstract
Neuropathic pain often fails to respond to conventional pain management procedures. here we review the aetiology of neuropathic pain as would result from peripheral neuropathy or injury. We show that inflammatory mediators released from damaged nerves and tissue are responsible for triggering ectopic activity in primary afferents and that this, in turn, provokes increased spinal cord activity and the development of ‘central sensitization’. Although evidence is mounting to support the role of interleukin-1β, prostaglandins and other cytokines in the onset of neuropathic pain, the clinical efficacy of drugs which antagonize or prevent the actions of these mediators is yet to be determined. basic science findings do, however, support the use of pre-emptive analgesia during procedures which involve nerve manipulation and the use of anti-inflammatory steroids as soon as possible following traumatic nerve injury.
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