1
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Qian X, Zhao X, Yu L, Yin Y, Zhang XD, Wang L, Li JX, Zhu Q, Luo JL. Current status of GABA receptor subtypes in analgesia. Biomed Pharmacother 2023; 168:115800. [PMID: 37935070 DOI: 10.1016/j.biopha.2023.115800] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 10/15/2023] [Accepted: 10/26/2023] [Indexed: 11/09/2023] Open
Abstract
Gamma-aminobutyric acid (GABA), a non-protein-producing amino acid synthesized from the excitatory amino acid glutamate via the enzyme glutamic acid decarboxylase, is extensively found in microorganisms, plants and vertebrates, and is abundantly expressed in the spinal cord and brain. It is the major inhibitory neurotransmitter in the mammalian nervous system. GABA plays crucial roles in the regulation of synaptic transmission, the promotion of neuronal development and relaxation, and the prevention of insomnia and depression. As the major inhibitory neurotransmitter, GABA plays pivotal roles in the regulation of pain sensation, which is initiated by the activation of peripheral nociceptors and transmitted to the spinal cord and brain along nerves. GABA exerts these roles by directly acting on three types of receptors: ionotropic GABAA and GABAC receptors and G protein-coupled GABAB receptor. The chloride-permeable ion channel receptors GABAA and GABAC mediate fast neurotransmission, while the metabotropic GABAB receptor mediates slow effect. Different GABA receptors regulate pain sensation via different signaling pathways. Here we highlight recent updates on the involvement of specific GABA receptors and their subtypes in the process of pain sensation. Further understanding of different GABA receptors and signaling pathways in pain sensation will benefit the development of novel analgesics for pain management by targeting specific GABA receptor subtypes and signaling pathways.
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Affiliation(s)
- Xunjia Qian
- School of Pharmacy, Nantong University, Nantong 226001, Jiangsu, China
| | - Xinyi Zhao
- School of Pharmacy, Nantong University, Nantong 226001, Jiangsu, China
| | - Lulu Yu
- School of Pharmacy, Nantong University, Nantong 226001, Jiangsu, China
| | - Yujian Yin
- School of Pharmacy, Nantong University, Nantong 226001, Jiangsu, China
| | - Xiao-Dan Zhang
- School of Pharmacy, Nantong University, Nantong 226001, Jiangsu, China
| | - Liyun Wang
- School of Pharmacy, Nantong University, Nantong 226001, Jiangsu, China
| | - Jun-Xu Li
- School of Pharmacy, Nantong University, Nantong 226001, Jiangsu, China; Provincial Key Laboratory of Inflammation and Molecular Drug Target, Nantong 226001, Jiangsu, China
| | - Qing Zhu
- School of Pharmacy, Nantong University, Nantong 226001, Jiangsu, China; Provincial Key Laboratory of Inflammation and Molecular Drug Target, Nantong 226001, Jiangsu, China.
| | - Jia-Lie Luo
- School of Pharmacy, Nantong University, Nantong 226001, Jiangsu, China.
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2
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Kababie-Ameo R, Gutiérrez-Salmeán G, Cuellar CA. Evidence of impaired H-reflex and H-reflex rate-dependent depression in diabetes, prediabetes and obesity: a mini-review. Front Endocrinol (Lausanne) 2023; 14:1206552. [PMID: 37476495 PMCID: PMC10354514 DOI: 10.3389/fendo.2023.1206552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Accepted: 06/12/2023] [Indexed: 07/22/2023] Open
Abstract
Diabetes Mellitus is a public health problem associated with complications such as neuropathy; however, it has been proposed that these may begin to develop during prediabetes and may also be present in persons with obesity. Diabetic peripheral neuropathy is the presence of signs and/or symptoms of peripheral nerve dysfunction in people living with diabetes, which increases the risk of developing complications and has a deleterious impact on quality of life. As part of the therapeutic protocol for diabetes, screening tests to identify peripheral neuropathy are suggested, however, there are no recommendations for people with prediabetes and obesity without symptoms such as pain, numbness, or paresthesias. Moreover, clinical screening tests that are usually used to recognize this alteration, such as tendon reflex, temperature sensation, and pressure and vibration perception, might be subjective as they depend on the evaluator's experience thus the incorrect application of these tests may not recognize the damage to small or large-nerve fibers. Recent evidence suggests that an objective study such as the impairment of the rate-dependent depression of the H-reflex could be used as a biomarker of spinal disinhibition and hence may provide more information on sensorimotor integration.
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Affiliation(s)
- Rebeca Kababie-Ameo
- Facultad de Ciencias de la Salud, Universidad Anáhuac Mexico, Huixquilucan, Estado de Mexico, Mexico
| | - Gabriela Gutiérrez-Salmeán
- Facultad de Ciencias de la Salud, Universidad Anáhuac Mexico, Huixquilucan, Estado de Mexico, Mexico
- Centro de Especialidades del Riñon (CER), Naucalpan de Juarez, Estado de Mexico, Mexico
| | - Carlos A. Cuellar
- Escuela de Ciencias del Deporte, Universidad Anahuac Mexico, Huixquilucan, Estado de Mexico, Mexico
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3
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Metz K, Matos IC, Hari K, Bseis O, Afsharipour B, Lin S, Singla R, Fenrich KK, Li Y, Bennett DJ, Gorassini MA. Post-activation depression from primary afferent depolarization (PAD) produces extensor H-reflex suppression following flexor afferent conditioning. J Physiol 2023; 601:1925-1956. [PMID: 36928599 PMCID: PMC11064783 DOI: 10.1113/jp283706] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 03/09/2023] [Indexed: 03/18/2023] Open
Abstract
Suppression of the extensor H-reflex by flexor afferent conditioning is thought to be produced by a long-lasting inhibition of extensor Ia afferent terminals via GABAA receptor-activated primary afferent depolarization (PAD). Given the recent finding that PAD does not produce presynaptic inhibition of Ia afferent terminals, we examined in 28 participants if H-reflex suppression is instead mediated by post-activation depression of the extensor Ia afferents triggered by PAD-evoked spikes and/or by a long-lasting inhibition of the extensor motoneurons. A brief conditioning vibration of the flexor tendon suppressed both the extensor soleus H-reflex and the tonic discharge of soleus motor units out to 150 ms following the vibration, suggesting that part of the H-reflex suppression during this period was mediated by postsynaptic inhibition of the extensor motoneurons. When activating the flexor afferents electrically to produce conditioning, the soleus H-reflex was also suppressed but only when a short-latency reflex was evoked in the soleus muscle by the conditioning input itself. In mice, a similar short-latency reflex was evoked when optogenetic or afferent activation of GABAergic (GAD2+ ) neurons produced a large enough PAD to evoke orthodromic spikes in the test Ia afferents, causing post-activation depression of subsequent monosynaptic EPSPs. The long duration of this post-activation depression and related H-reflex suppression (seconds) was similar to rate-dependent depression that is also due to post-activation depression. We conclude that extensor H-reflex inhibition by brief flexor afferent conditioning is produced by both post-activation depression of extensor Ia afferents and long-lasting inhibition of extensor motoneurons, rather than from PAD inhibiting Ia afferent terminals. KEY POINTS: Suppression of extensor H-reflexes by flexor afferent conditioning was thought to be mediated by GABAA receptor-mediated primary afferent depolarization (PAD) shunting action potentials in the Ia afferent terminal. In line with recent findings that PAD has a facilitatory role in Ia afferent conduction, we show here that when large enough, PAD can evoke orthodromic spikes that travel to the Ia afferent terminal to evoke EPSPs in the motoneuron. These PAD-evoked spikes also produce post-activation depression of Ia afferent terminals and may mediate the short- and long-lasting suppression of extensor H-reflexes in response to flexor afferent conditioning. Our findings highlight that we must re-examine how changes in the activation of GABAergic interneurons and PAD following nervous system injury or disease affects the regulation of Ia afferent transmission to spinal neurons and ultimately motor dysfunction in these disorders.
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Affiliation(s)
- Krista Metz
- Biomedical Engineering, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
| | - Isabel Concha Matos
- Biomedical Engineering, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
| | - Krishnapriya Hari
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
- Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, Canada
| | - Omayma Bseis
- Biomedical Engineering, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
| | - Babak Afsharipour
- Biomedical Engineering, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
| | - Shihao Lin
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
- Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, Canada
| | - Rahul Singla
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
- Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, Canada
| | - Keith K Fenrich
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
- Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, Canada
| | - Yaqing Li
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
- Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, Canada
| | - David J Bennett
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
- Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, Canada
| | - Monica A Gorassini
- Biomedical Engineering, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
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4
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Rodríguez-Palma EJ, De la Luz-Cuellar YE, Islas-Espinoza AM, Félix-Leyva AE, Shiers SI, García G, Torres-Lopez JE, Delgado-Lezama R, Murbartián J, Price TJ, Granados-Soto V. Activation of α 6 -containing GABA A receptors induces antinociception under physiological and pathological conditions. Pain 2023; 164:948-966. [PMID: 36001074 PMCID: PMC9950299 DOI: 10.1097/j.pain.0000000000002763] [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: 02/23/2022] [Accepted: 08/15/2022] [Indexed: 11/26/2022]
Abstract
ABSTRACT The loss of GABAergic inhibition is a mechanism that underlies neuropathic pain. Therefore, rescuing the GABAergic inhibitory tone through the activation of GABA A receptors is a strategy to reduce neuropathic pain. This study was designed to elucidate the function of the spinal α 6 -containing GABA A receptor in physiological conditions and neuropathic pain in female and male rats. Results show that α 6 -containing GABA A receptor blockade or transient α 6 -containing GABA A receptor knockdown induces evoked hypersensitivity and spontaneous pain in naive female rats. The α 6 subunit is expressed in IB4 + and CGRP + primary afferent neurons in the rat spinal dorsal horn and dorsal root ganglia but not astrocytes. Nerve injury reduces α 6 subunit protein expression in the central terminals of the primary afferent neurons and dorsal root ganglia, whereas intrathecal administration of positive allosteric modulators of the α 6 -containing GABA A receptor reduces tactile allodynia and spontaneous nociceptive behaviors in female, but not male, neuropathic rats and mice. Overexpression of the spinal α 6 subunit reduces tactile allodynia and restores α 6 subunit expression in neuropathic rats. Positive allosteric modulators of the α 6 -containing GABA A receptor induces a greater antiallodynic effect in female rats and mice compared with male rats and mice. Finally, α 6 subunit is expressed in humans. This receptor is found in CGRP + and P2X3 + primary afferent fibers but not astrocytes in the human spinal dorsal horn. Our results suggest that the spinal α 6 -containing GABA A receptor has a sex-specific antinociceptive role in neuropathic pain, suggesting that this receptor may represent an interesting target to develop a novel treatment for neuropathic pain.
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Affiliation(s)
- Erick J. Rodríguez-Palma
- Neurobiology of Pain Laboratory, Departamento de Farmacobiología, Cinvestav, South Campus, Mexico City, Mexico
| | - Yarim E. De la Luz-Cuellar
- Neurobiology of Pain Laboratory, Departamento de Farmacobiología, Cinvestav, South Campus, Mexico City, Mexico
| | - Ana M. Islas-Espinoza
- Neurobiology of Pain Laboratory, Departamento de Farmacobiología, Cinvestav, South Campus, Mexico City, Mexico
| | - Adalberto E. Félix-Leyva
- Neurobiology of Pain Laboratory, Departamento de Farmacobiología, Cinvestav, South Campus, Mexico City, Mexico
- Facultad de Biología, Universidad Autónoma de Sinaloa, Culiacán, Sinaloa, Mexico
| | - Stephanie I. Shiers
- School of Behavioral and Brain Sciences, Center for Advanced Pain Studies, University of Texas at Dallas, Richardson, TX, USA
| | - Guadalupe García
- Departamento de Farmacobiología, Cinvestav, South Campus, Mexico City, Mexico
| | - Jorge E. Torres-Lopez
- Laboratorio de Mecanismos de Dolor, División Académica de Ciencias de la Salud, Universidad Juárez Autónoma de Tabasco, Villahermosa, Tabasco, Mexico
| | - Rodolfo Delgado-Lezama
- Departamento de Fisiología, Biofísica y Neurociencias, Cinvestav, Zacatenco, Mexico City, Mexico
| | - Janet Murbartián
- Departamento de Farmacobiología, Cinvestav, South Campus, Mexico City, Mexico
| | - Theodore J. Price
- School of Behavioral and Brain Sciences, Center for Advanced Pain Studies, University of Texas at Dallas, Richardson, TX, USA
| | - Vinicio Granados-Soto
- Neurobiology of Pain Laboratory, Departamento de Farmacobiología, Cinvestav, South Campus, Mexico City, Mexico
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5
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Salinas LF, Trujillo-Condes VE, Tecuatl C, Delgado-Lezama R, Cuellar CA. Impaired rate-dependent depression of the H-reflex in type-2 diabetes, prediabetes, overweight and obesity: A cross-sectional study. Medicine (Baltimore) 2022; 101:e31046. [PMID: 36316945 PMCID: PMC9622671 DOI: 10.1097/md.0000000000031046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Type-2 diabetes is a chronic metabolic disorder characterized by hyperglycemia, resulting from deficits in insulin secretion or insulin resistance. According to the International Diabetes Federation, approximately 463 million people suffered from this condition in 2019, with a rapidly increasing impact in low-and middle-income countries. Obesity is a well-known risk factor for diabetes, and current data project a continuous increase in diabetes prevalence worldwide in obese individuals. Among the common complications, diabetic peripheral neuropathy (DPN) causes sensory symptoms, including pain that contributes to foot ulceration, and if not controlled, limb amputation may occur. The diagnosis of DPN is a clinical problem. Rate-dependent depression (RDD) of the Hoffmann reflex in the lower limbs has been proposed as a test to determine the presence of neuropathic pain in subjects with type-1 and type-2 diabetes. Recently, impaired RDD has been described in obese and diabetic rodent models. In this study, we characterized the RDD by evaluating the H-reflex at 0.2, 1, 2, 5, and 10 Hz in 39 patients with type-2 Diabetes mellitus (T2DM) and 42 controls without diabetes, subsequently classified as overweight/obese and prediabetic. A significant decrease in the RDD of the H-reflex was found in T2DM subjects at 1, 2, 5, and 10 Hz (P < .001) stimulation frequencies compared to controls, but not at 0.2 Hz (P = .48). A major finding of this study is that impaired RDD was also found in 11/25 overweight and obese subjects in at least 2 stimulation frequencies, being 10 of those classified in prediabetic levels according to their HbA1C values. The RDD of the H-reflex could be used as a quantitative and sensitive tool to study T2DM subpopulations with peripheral neuropathy. RDD could be used as a screening tool in combination with clinical tests to diagnose DPN and evaluate the progression of this condition.
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Affiliation(s)
- Luisa Fernanda Salinas
- Faculty of Medicine, Universidad Autónoma del Estado de México, Av. Paseo Tollocan, C. Jesús Carranza, Estado DE México, México
| | | | - Carolina Tecuatl
- Center for Neural Informatics, Structures, & Plasticity, Krasnow Institute for Advanced Study; and Department of Bioengineering, Volgenau School of Engineering, George Mason University, Fairfax, VA, USA
| | - Rodolfo Delgado-Lezama
- Departamento de Fisiología, Biofísica y Neurociencias, Cinvestav, Av. Instituto Politécnico Nacional 2508, México City, México
| | - Carlos A Cuellar
- School of Sport Sciences, Universidad Anáhuac México, Av. Universidad Anáhuac 46, Estado DE México, México
- *Correspondence: Carlos A Cuellar, School of Sport Sciences, Universidad Anáhuac México, Av. Universidad Anáhuac 46, Lomas Anáhuac, 52786, Huixquilucan, Estado DE México, México (e-mail: )
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6
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Cerne R, Lippa A, Poe MM, Smith JL, Jin X, Ping X, Golani LK, Cook JM, Witkin JM. GABAkines - Advances in the discovery, development, and commercialization of positive allosteric modulators of GABA A receptors. Pharmacol Ther 2022; 234:108035. [PMID: 34793859 PMCID: PMC9787737 DOI: 10.1016/j.pharmthera.2021.108035] [Citation(s) in RCA: 57] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 11/08/2021] [Indexed: 12/25/2022]
Abstract
Positive allosteric modulators of γ-aminobutyric acid-A (GABAA) receptors or GABAkines have been widely used medicines for over 70 years for anxiety, epilepsy, sleep, and other disorders. Traditional GABAkines like diazepam have safety and tolerability concerns that include sedation, motor-impairment, respiratory depression, tolerance and dependence. Multiple GABAkines have entered clinical development but the issue of side-effects has not been fully solved. The compounds that are presently being developed and commercialized include several neuroactive steroids (an allopregnanolone formulation (brexanolone), an allopregnanolone prodrug (LYT-300), Sage-324, zuranolone, and ganaxolone), the α2/3-preferring GABAkine, KRM-II-81, and the α2/3/5-preferring GABAkine PF-06372865 (darigabat). The neuroactive steroids are in clinical development for post-partum depression, intractable epilepsy, tremor, status epilepticus, and genetic epilepsy disorders. Darigabat is in development for epilepsy and anxiety. The imidazodiazepine, KRM-II-81 is efficacious in animal models for the treatment of epilepsy and post-traumatic epilepsy, acute and chronic pain, as well as anxiety and depression. The efficacy of KRM-II-81 in models of pharmacoresistant epilepsy, preventing the development of seizure sensitization, and in brain tissue of intractable epileptic patients bodes well for improved therapeutics. Medicinal chemistry efforts are also ongoing to identify novel and improved GABAkines. The data document gaps in our understanding of the molecular pharmacology of GABAkines that drive differential pharmacological profiles, but emphasize advancements in the ability to successfully utilize GABAA receptor potentiation for therapeutic gain in neurology and psychiatry.
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Affiliation(s)
- Rok Cerne
- Laboratory of Antiepileptic Drug Discovery, Ascension St. Vincent, Indianapolis, IN USA,Faculty of Medicine, University of Ljubljana, Zaloška cesta 4, Ljubljana, Slovenia.,RespireRx Pharmaceuticals Inc, Glen Rock, NJ, USA,Department of Anatomy and Cell Biology, Indiana University/Purdue University, Indianapolis, IN, USA
| | - Arnold Lippa
- RespireRx Pharmaceuticals Inc, Glen Rock, NJ, USA
| | | | - Jodi L. Smith
- Laboratory of Antiepileptic Drug Discovery, Ascension St. Vincent, Indianapolis, IN USA
| | - Xiaoming Jin
- Department of Anatomy and Cell Biology, Indiana University/Purdue University, Indianapolis, IN, USA
| | - Xingjie Ping
- Department of Anatomy and Cell Biology, Indiana University/Purdue University, Indianapolis, IN, USA
| | - Lalit K. Golani
- Department of Chemistry and Biochemistry, Milwaukee Institute of Drug Discovery, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| | - James M. Cook
- RespireRx Pharmaceuticals Inc, Glen Rock, NJ, USA,Department of Chemistry and Biochemistry, Milwaukee Institute of Drug Discovery, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| | - Jeffrey M. Witkin
- Laboratory of Antiepileptic Drug Discovery, Ascension St. Vincent, Indianapolis, IN USA,RespireRx Pharmaceuticals Inc, Glen Rock, NJ, USA,Department of Chemistry and Biochemistry, Milwaukee Institute of Drug Discovery, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
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7
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Delgado‐Lezama R, Bravo‐Hernández M, Franco‐Enzástiga Ú, De la Luz‐Cuellar YE, Alvarado‐Cervantes NS, Raya‐Tafolla G, Martínez‐Zaldivar LA, Vargas‐Parada A, Rodríguez‐Palma EJ, Vidal‐Cantú GC, Guzmán‐Priego CG, Torres‐López JE, Murbartián J, Felix R, Granados‐Soto V. The role of spinal cord extrasynaptic α 5 GABA A receptors in chronic pain. Physiol Rep 2021; 9:e14984. [PMID: 34409771 PMCID: PMC8374381 DOI: 10.14814/phy2.14984] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2021] [Revised: 06/25/2021] [Accepted: 06/29/2021] [Indexed: 11/24/2022] Open
Abstract
Chronic pain is an incapacitating condition that affects a large population worldwide. Until now, there is no drug treatment to relieve it. The impairment of GABAergic inhibition mediated by GABAA receptors (GABAA R) is considered a relevant factor in mediating chronic pain. Even though both synaptic and extrasynaptic GABAA inhibition are present in neurons that process nociceptive information, the latter is not considered relevant as a target for the development of pain treatments. In particular, the extrasynaptic α5 GABAA Rs are expressed in laminae I-II of the spinal cord neurons, sensory neurons, and motoneurons. In this review, we discuss evidence showing that blockade of the extrasynaptic α5 GABAA Rs reduces mechanical allodynia in various models of chronic pain and restores the associated loss of rate-dependent depression of the Hoffmann reflex. Furthermore, in healthy animals, extrasynaptic α5 GABAA R blockade induces both allodynia and hyperalgesia. These results indicate that this receptor may have an antinociceptive and pronociceptive role in healthy and chronic pain-affected animals, respectively. We propose a hypothesis to explain the relevant role of the extrasynaptic α5 GABAA Rs in the processing of nociceptive information. The data discussed here strongly suggest that this receptor could be a valid pharmacological target to treat chronic pain states.
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Affiliation(s)
| | - Mariana Bravo‐Hernández
- Neuroregeneration LaboratoryDepartment of AnesthesiologyUniversity of CaliforniaSan Diego, La JollaCAUSA
| | | | | | | | | | | | | | | | | | - Crystell G. Guzmán‐Priego
- Mechanisms of Pain LaboratoryDivisión Académica de Ciencias de la SaludUniversidad Juárez Autónoma de Tabasco, VillahermosaTabascoMexico
| | - Jorge E. Torres‐López
- Mechanisms of Pain LaboratoryDivisión Académica de Ciencias de la SaludUniversidad Juárez Autónoma de Tabasco, VillahermosaTabascoMexico
- Hospital Regional de Alta Especialidad “Dr. Juan Graham Casasús”, VillahermosaTabascoMexico
| | | | - Ricardo Felix
- Departamento de Biología CelularCinvestavMexico CityMexico
| | - Vinicio Granados‐Soto
- Neurobiology of Pain LaboratoryDepartamento de FarmacobiologíaCinvestavMexico CityMexico
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8
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Ye LX, Huang HH, Zhang SH, Lu JS, Cao DX, Wu DD, Chi PW, Hong LH, Wu MX, Xu Y, Yu CX. Streptozotocin-Induced Hyperglycemia Affects the Pharmacokinetics of Koumine and its Anti-Allodynic Action in a Rat Model of Diabetic Neuropathic Pain. Front Pharmacol 2021; 12:640318. [PMID: 34054521 PMCID: PMC8156416 DOI: 10.3389/fphar.2021.640318] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 04/26/2021] [Indexed: 11/17/2022] Open
Abstract
Koumine (KM), the most abundant alkaloid in Gelsemium elegans, has anti-neuropathic, anti-inflammatory, and analgesic activities; thus, it has the potential to be developed as a broad-spectrum analgesic drug. However, factors determining the relationship between analgesic efficacy and the corresponding plasma KM concentration are largely unclear. The pharmacokinetics and pharmacodynamics of KM and their optimization in the context of neuropathic pain have not been reported. We investigated the pharmacokinetics and pharmacodynamics of KM after oral administration in a streptozotocin-induced rat model of diabetic neuropathic pain (DNP) using a population approach. A first-order absorption and elimination pharmacokinetics model best described the plasma KM concentration. This pharmacokinetic model was then linked to a linear pharmacodynamic model with an effect compartment based on the measurement of the mechanical withdrawal threshold. KM was rapidly absorbed (time to maximum plasma concentration: 0.14–0.36 h) with similar values in both DNP and naïve rats, suggesting that DNP did not influence the KM absorption rate. However, the area under the curve (AUC0–∞) of KM in DNP rats was over 3-fold higher than that in naïve rats. The systemic clearance rate and volume of KM distribution were significantly lower in DNP rats than in naïve rats. Blood glucose value prior to KM treatment was a significant covariate for the systemic clearance rate of KM and baseline value of the threshold. Our results suggest that streptozotocin-induced hyperglycemia is an independent factor for decreased KM elimination and its anti-allodynic effects in a DNP rat model. To the best of our knowledge, this is the first study to investigate the role of DNP in the pharmacokinetics and pharmacokinetics-pharmacodynamics of KM in streptozotocin-induced diabetic rats.
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Affiliation(s)
- Li-Xiang Ye
- Fujian Center for Safety Evaluation of New Drug, Fujian Medical University, Fuzhou, China
| | - Hui-Hui Huang
- Department of Pharmacology, College of Pharmacy, Fujian Medical University, Fuzhou, China.,Fujian Key Laboratory of Natural Medicine Pharmacology, Fujian Medical University, Fuzhou, China.,Fujian Key Laboratory of Drug Target Discovery and Structural and Functional Research, Fuzhou, China
| | - Shui-Hua Zhang
- Fujian Center for Safety Evaluation of New Drug, Fujian Medical University, Fuzhou, China
| | - Jing-Shan Lu
- Department of Pharmacology, College of Pharmacy, Fujian Medical University, Fuzhou, China
| | - Da-Xuan Cao
- Fujian Center for Safety Evaluation of New Drug, Fujian Medical University, Fuzhou, China
| | - Dan-Dan Wu
- Fujian Center for Safety Evaluation of New Drug, Fujian Medical University, Fuzhou, China
| | - Pei-Wang Chi
- Fujian Center for Safety Evaluation of New Drug, Fujian Medical University, Fuzhou, China
| | - Long-Hui Hong
- Fujian Center for Safety Evaluation of New Drug, Fujian Medical University, Fuzhou, China
| | - Min-Xia Wu
- Electron Microscopy Laboratory of Public Technology Service Center, Fujian Medical University, Fuzhou, China
| | - Ying Xu
- Department of Pharmacology, College of Pharmacy, Fujian Medical University, Fuzhou, China.,Fujian Key Laboratory of Natural Medicine Pharmacology, Fujian Medical University, Fuzhou, China.,Fujian Key Laboratory of Drug Target Discovery and Structural and Functional Research, Fuzhou, China
| | - Chang-Xi Yu
- Department of Pharmacology, College of Pharmacy, Fujian Medical University, Fuzhou, China.,Fujian Key Laboratory of Natural Medicine Pharmacology, Fujian Medical University, Fuzhou, China.,Fujian Key Laboratory of Drug Target Discovery and Structural and Functional Research, Fuzhou, China
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9
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Drexler B, Grenz J, Grasshoff C, Antkowiak B. Allopregnanolone Enhances GABAergic Inhibition in Spinal Motor Networks. Int J Mol Sci 2020; 21:ijms21197399. [PMID: 33036451 PMCID: PMC7582554 DOI: 10.3390/ijms21197399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 09/28/2020] [Accepted: 10/01/2020] [Indexed: 11/16/2022] Open
Abstract
The neurosteroid allopregnanolone (ALLO) causes unconsciousness by allosteric modulation of γ-aminobutyric acid type A (GABAA) receptors, but its actions on the spinal motor networks are unknown. We are therefore testing the hypothesis that ALLO attenuates the action potential firing of spinal interneurons and motoneurons predominantly via enhancing tonic, but not synaptic GABAergic inhibition. We used video microscopy to assess motoneuron-evoked muscle activity in organotypic slice cultures prepared from the spinal cord and muscle tissue. Furthermore, we monitored GABAA receptor-mediated currents by performing whole-cell voltage-clamp recordings. We found that ALLO (100 nM) reduced the action potential firing of spinal interneurons by 27% and that of α-motoneurons by 33%. The inhibitory effects of the combination of propofol (1 µM) and ALLO on motoneuron-induced muscle contractions were additive. Moreover, ALLO evoked a tonic, GABAA receptor-mediated current (amplitude: 41 pA), without increasing phasic GABAergic transmission. Since we previously showed that at a clinically relevant concentration of 1 µM propofol enhanced phasic, but not tonic GABAergic inhibition, we conclude that ALLO and propofol target distinct subpopulations of GABAA receptors. These findings provide first evidence that the combined application of ALLO and propofol may help to reduce intraoperative movements and undesired side effects that are frequently observed under total intravenous anesthesia.
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γ-Aminobutyric acid (GABA) from satellite glial cells tonically depresses the excitability of primary afferent fibers. Neurosci Res 2020; 170:50-58. [PMID: 32987088 DOI: 10.1016/j.neures.2020.08.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 08/10/2020] [Accepted: 08/26/2020] [Indexed: 01/08/2023]
Abstract
Primary afferent fibers express extrasynaptic GABAA and GABAB receptors in the axons and soma. However, whether these receptors are tonically activated by ambient GABA and the source of the neurotransmitter is presently unknown. Here, we show that GABA release from dorsal root ganglia (DRG) does not depend on extracellular calcium, but depends upon calcium released from intracellular stores, and is mediated by Best1 channels. Using a preparation consisting of the spinal nerve in continuity with the DRG and the dorsal root, we found that endogenous GABA tonically activates GABA receptors, depressing the excitability of the primary afferents. In addition, using HPLC we found that GABA is released in the DRG, and by immunofluorescence microscopy we show the presence of GABA, the Best1 channel, and some enzymes of the putrescine pathway of GABA biosynthesis, in glutamine synthase- and GFAP-positive satellite glial cells. Last, we found that the blockade of the Best1 channel activity reduced the excitability of primary afferents and prevented the activation of the GABA receptors. These results suggest that satellite glial cells may be the source of endogenous GABA released in the DRG via Best1 channels, which tonically activates extrasynaptic GABA receptors.
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Franco-Enzástiga Ú, García G, Murbartián J, González-Barrios R, Salinas-Abarca AB, Sánchez-Hernández B, Tavares-Ferreira D, Herrera LA, Barragán-Iglesias P, Delgado-Lezama R, Price TJ, Granados-Soto V. Sex-dependent pronociceptive role of spinal α 5 -GABA A receptor and its epigenetic regulation in neuropathic rodents. J Neurochem 2020; 156:897-916. [PMID: 32750173 DOI: 10.1111/jnc.15140] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 06/26/2020] [Accepted: 07/22/2020] [Indexed: 12/23/2022]
Abstract
Extrasynaptic α5 -subunit containing GABAA (α5 -GABAA ) receptors participate in chronic pain. Previously, we reported a sex difference in the action of α5 -GABAA receptors in dysfunctional pain. However, the underlying mechanisms remain unknown. The aim of this study was to examine this sexual dimorphism in neuropathic rodents and the mechanisms involved. Female and male Wistar rats or ICR mice were subjected to nerve injury followed by α5 -GABAA receptor inverse agonist intrathecal administration, L-655,708. The drug produced an antiallodynic effect in nerve-injured female rats and mice, and a lower effect in males. We hypothesized that changes in α5 -GABAA receptor, probably influenced by hormonal and epigenetic status, might underlie this sex difference. Thus, we performed qPCR and western blot. Nerve injury increased α5 -GABAA mRNA and protein in female dorsal root ganglia (DRG) and decreased them in DRG and spinal cord of males. To investigate the hormonal influence over α5 -GABAA receptor actions, we performed nerve injury to ovariectomized rats and reconstituted them with 17β-estradiol (E2). Ovariectomy abrogated L-655,708 antiallodynic effect and E2 restored it. Ovariectomy decreased α5 -GABAA receptor and estrogen receptor α protein in DRG of neuropathic female rats, while E2 enhanced them. Since DNA methylation might contribute to α5 -GABAA receptor down-regulation in males, we examined CpG island DNA methylation of α5 -GABAA receptor coding gene through pyrosequencing. Nerve injury increased methylation in male, but not female rats. Pharmacological inhibition of DNA methyltransferases increased α5 -GABAA receptor and enabled L-655,708 antinociceptive effect in male rats. These results suggest that α5 -GABAA receptor is a suitable target to treat chronic pain in females.
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Affiliation(s)
- Úrzula Franco-Enzástiga
- Neurobiology of Pain Laboratory, Departamento de Farmacobiología, Cinvestav, South Campus, Mexico City, Mexico
| | - Guadalupe García
- Departamento de Farmacobiología, Cinvestav, South Campus, Mexico City, Mexico
| | - Janet Murbartián
- Departamento de Farmacobiología, Cinvestav, South Campus, Mexico City, Mexico
| | | | - Ana B Salinas-Abarca
- Neurobiology of Pain Laboratory, Departamento de Farmacobiología, Cinvestav, South Campus, Mexico City, Mexico
| | - Beatriz Sánchez-Hernández
- Departamento de Genética, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
| | - Diana Tavares-Ferreira
- School of Behavioral and Brain Sciences, Center for Advanced Pain Studies, University of Texas at Dallas, Richardson, TX, USA
| | - Luis A Herrera
- Cancer Biomedical Research Unit, Instituto Nacional de Cancerología, Mexico City, Mexico
| | - Paulino Barragán-Iglesias
- School of Behavioral and Brain Sciences, Center for Advanced Pain Studies, University of Texas at Dallas, Richardson, TX, USA.,Department of Physiology and Pharmacology, Center for Basic Sciences, Autonomous University of Aguascalientes, Aguascalientes, Mexico
| | - Rodolfo Delgado-Lezama
- Departamento de Fisiología, Biofísica y Neurociencias, Cinvestav, Zacatenco, Mexico City, Mexico
| | - Theodore J Price
- School of Behavioral and Brain Sciences, Center for Advanced Pain Studies, University of Texas at Dallas, Richardson, TX, USA
| | - Vinicio Granados-Soto
- Neurobiology of Pain Laboratory, Departamento de Farmacobiología, Cinvestav, South Campus, Mexico City, Mexico
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