1
|
Shan Y, Zhao J, Zheng Y, Guo S, Schrodi SJ, He D. Understanding the function of the GABAergic system and its potential role in rheumatoid arthritis. Front Immunol 2023; 14:1114350. [PMID: 36825000 PMCID: PMC9941139 DOI: 10.3389/fimmu.2023.1114350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Accepted: 01/26/2023] [Indexed: 02/10/2023] Open
Abstract
Rheumatoid arthritis (RA) is a highly disabling chronic autoimmune disease. Multiple factors contribute to the complex pathological process of RA, in which an abnormal autoimmune response, high survival of inflammatory cells, and excessive release of inflammatory factors lead to a severe chronic inflammatory response. Clinical management of RA remains limited; therefore, exploring and discovering new mechanisms of action could enhance clinical benefits for patients with RA. Important bidirectional communication occurs between the brain and immune system in inflammatory diseases such as RA, and circulating immune complexes can cause neuroinflammatory responses in the brain. The gamma-aminobutyric acid (GABA)ergic system is a part of the nervous system that primarily comprises GABA, GABA-related receptors, and GABA transporter (GAT) systems. GABA is an inhibitory neurotransmitter that binds to GABA receptors in the presence of GATs to exert a variety of pathophysiological regulatory effects, with its predominant role being neural signaling. Nonetheless, the GABAergic system may also have immunomodulatory effects. GABA/GABA-A receptors may inhibit the progression of inflammation in RA and GATs may promote inflammation. GABA-B receptors may also act as susceptibility genes for RA, regulating the inflammatory response of RA via immune cells. Furthermore, the GABAergic system may modulate the abnormal pain response in RA patients. We also summarized the latest clinical applications of the GABAergic system and provided an outlook on its clinical application in RA. However, direct studies on the GABAergic system and RA are still lacking; therefore, we hope to provide potential therapeutic options and a theoretical basis for RA treatment by summarizing any potential associations.
Collapse
Affiliation(s)
- Yu Shan
- Department of Rheumatology, Shanghai Guanghua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China,Guanghua Clinical Medical College, Shanghai University of Traditional Chinese Medicine, Shanghai, China,Institute of Arthritis Research in Integrative Medicine, Shanghai Academy of Traditional Chinese Medicine, Shanghai, China
| | - Jianan Zhao
- Department of Rheumatology, Shanghai Guanghua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China,Guanghua Clinical Medical College, Shanghai University of Traditional Chinese Medicine, Shanghai, China,Institute of Arthritis Research in Integrative Medicine, Shanghai Academy of Traditional Chinese Medicine, Shanghai, China
| | - Yixin Zheng
- Department of Rheumatology, Shanghai Guanghua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China,Guanghua Clinical Medical College, Shanghai University of Traditional Chinese Medicine, Shanghai, China,Institute of Arthritis Research in Integrative Medicine, Shanghai Academy of Traditional Chinese Medicine, Shanghai, China
| | - Shicheng Guo
- Computation and Informatics in Biology and Medicine, University of Wisconsin-Madison, Madison, WI, United States,Department of Medical Genetics, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, United States,*Correspondence: Shicheng Guo, ; Steven J. Schrodi, ; Dongyi He,
| | - Steven J. Schrodi
- Computation and Informatics in Biology and Medicine, University of Wisconsin-Madison, Madison, WI, United States,Department of Medical Genetics, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, United States,*Correspondence: Shicheng Guo, ; Steven J. Schrodi, ; Dongyi He,
| | - Dongyi He
- Department of Rheumatology, Shanghai Guanghua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China,Guanghua Clinical Medical College, Shanghai University of Traditional Chinese Medicine, Shanghai, China,Institute of Arthritis Research in Integrative Medicine, Shanghai Academy of Traditional Chinese Medicine, Shanghai, China,Arthritis Institute of Integrated Traditional and Western medicine, Shanghai Chinese Medicine Research Institute, Shanghai, China,*Correspondence: Shicheng Guo, ; Steven J. Schrodi, ; Dongyi He,
| |
Collapse
|
2
|
Łątka K, Jończyk J, Bajda M. Structure modeling of γ-aminobutyric acid transporters - Molecular basics of ligand selectivity. Int J Biol Macromol 2020; 158:S0141-8130(20)33135-4. [PMID: 32376252 DOI: 10.1016/j.ijbiomac.2020.04.263] [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: 03/31/2020] [Revised: 04/28/2020] [Accepted: 04/29/2020] [Indexed: 11/15/2022]
Abstract
γ-Aminobutyric acid transporters are responsible for regulating the GABA level in the synaptic cleft. In this way, they affect GABA-ergic transmission which is important for the proper functioning of the central nervous system. The exact structure of GABA transporters is still unknown, which hinders the design of new, potent and selective inhibitors. For these reasons, we decided to create models of all types of human gamma-aminobutyric acid transporters. They were built based on crystal structures of related proteins from the SLC6 family using homology modeling methods. The reliability of the received models has been confirmed by a number of tools assessing the quality of protein models. To determine the ligand binding mode and indicate the amino acids responsible for selectivity, docking studies and molecular dynamics simulations were performed. The amino acids lining the bottom of the main binding site have a major impact on the selective ligand binding. In addition, an important element is the non-helical fragment of the transmembrane domain 10, and several amino acids within the vestibule of the transporters, which affect its volume. To check whether obtained models are suitable to distinguish active compounds from inactive ones, enrichment plots were prepared. Results suggest that our models may be useful in the search for new inhibitors of GABA transporters of the desired selectivity.
Collapse
Affiliation(s)
- Kamil Łątka
- Jagiellonian University Medical College, Faculty of Pharmacy, Department of Physicochemical Drug Analysis, 30-688 Cracow, Medyczna 9, Poland
| | - Jakub Jończyk
- Jagiellonian University Medical College, Faculty of Pharmacy, Department of Physicochemical Drug Analysis, 30-688 Cracow, Medyczna 9, Poland
| | - Marek Bajda
- Jagiellonian University Medical College, Faculty of Pharmacy, Department of Physicochemical Drug Analysis, 30-688 Cracow, Medyczna 9, Poland.
| |
Collapse
|
3
|
Łątka K, Jończyk J, Bajda M. γ-Aminobutyric acid transporters as relevant biological target: Their function, structure, inhibitors and role in the therapy of different diseases. Int J Biol Macromol 2020; 158:S0141-8130(20)32987-1. [PMID: 32360967 DOI: 10.1016/j.ijbiomac.2020.04.126] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 04/17/2020] [Accepted: 04/18/2020] [Indexed: 12/13/2022]
Abstract
γ-Aminobutyric acid (GABA) is a major inhibitory neurotransmitter in the nervous system. It plays a crucial role in many physiological processes. Upon release from the presynaptic element, it is removed from the synaptic cleft by reuptake due to the action of GABA transporters (GATs). GATs belong to a large SLC6 protein family whose characteristic feature is sodium-dependent relocation of neurotransmitters through the cell membrane. GABA transporters are characterized in many contexts, but their spatial structure is not fully known. They are divided into four types, which differ in occurrence and role. Herein, the special attention was paid to these transporting proteins. This comprehensive review presents the current knowledge about GABA transporters. Their distribution in the body, physiological functions and possible utilization in the therapy of different diseases were fully discussed. The important structural features were described based on published data, including sequence analysis, mutagenesis studies, and comparison with known SLC6 transporters for leucine (LeuT), dopamine (DAT) and serotonin (SERT). Moreover, the most important inhibitors of GABA transporters of various basic scaffolds, diverse selectivity and potency were presented.
Collapse
Affiliation(s)
- Kamil Łątka
- Jagiellonian University Medical College, Faculty of Pharmacy, Department of Physicochemical Drug Analysis, 30-688 Cracow, Medyczna 9, Poland
| | - Jakub Jończyk
- Jagiellonian University Medical College, Faculty of Pharmacy, Department of Physicochemical Drug Analysis, 30-688 Cracow, Medyczna 9, Poland
| | - Marek Bajda
- Jagiellonian University Medical College, Faculty of Pharmacy, Department of Physicochemical Drug Analysis, 30-688 Cracow, Medyczna 9, Poland.
| |
Collapse
|
4
|
Ge MM, Chen SP, Zhou YQ, Li Z, Tian XB, Gao F, Manyande A, Tian YK, Yang H. The therapeutic potential of GABA in neuron-glia interactions of cancer-induced bone pain. Eur J Pharmacol 2019; 858:172475. [DOI: 10.1016/j.ejphar.2019.172475] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 06/17/2019] [Accepted: 06/18/2019] [Indexed: 01/06/2023]
|
5
|
Enhanced Thalamic Spillover Inhibition during Non-rapid-eye-movement Sleep Triggers an Electrocortical Signature of Anesthetic Hypnosis. Anesthesiology 2017; 125:964-978. [PMID: 27552653 DOI: 10.1097/aln.0000000000001307] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Alterations in thalamic γ-aminobutyric acid-mediated signaling are thought to underlie the increased frontal α-β frequency electrocortical activity that signals anesthetic-induced loss of consciousness with γ-aminobutyric acid receptor type A (GABAAR)-targeting general anesthetics. The general anesthetic etomidate elicits phasic extrasynaptic GABAAR activation ("spillover" inhibition) at thalamocortical neurons in vitro. We hypothesize that this action of etomidate at the thalamus is sufficient to trigger an increase in frontal α-β frequency electrocortical activity and that this effect of etomidate is fully recapitulated by enhanced thalamic spillover inhibition in vivo. METHODS We recorded electrocortical activity and sleep-wake behavior in freely behaving wild-type (n = 33) and extrasynaptic δ-subunit-containing GABAAR knockout mice (n = 9) during bilateral microperfusion of the thalamus with etomidate and/or other pharmacologic agents that influence GABAAR or T-type Ca channel activity. RESULTS Microperfusion of etomidate into the thalamus elicited an increase in α-β frequency electrocortical activity that occurred only during non-rapid-eye-movement (REM) sleep (11.0 ± 11.8% and 16.0 ± 14.2% greater 8 to 12- and 12 to 30-Hz power, respectively; mean ± SD; both P < 0.031) and was not affected by blockade of thalamic T-type Ca channels. Etomidate at the thalamus also increased spindle-like oscillations during non-REM sleep (4.5 ± 2.4 spindle per minute with etomidate vs. 3.2 ± 1.7 at baseline; P = 0.002). These effects of etomidate were fully recapitulated by enhanced thalamic extrasynaptic GABAAR-mediated spillover inhibition. CONCLUSIONS These findings identify how a prototypic GABAAR-targeting general anesthetic agent can elicit the characteristic brain wave pattern associated with anesthetic hypnosis when acting at the thalamus by promoting spillover inhibition and the necessity of a preexisting non-REM mode of activity in the thalamus to generate this effect.
Collapse
|
6
|
Accumulated GABA activates presynaptic GABAB receptors and inhibits both excitatory and inhibitory synaptic transmission in rat midbrain periaqueductal gray. Neuroreport 2017; 28:313-318. [DOI: 10.1097/wnr.0000000000000756] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
|
7
|
Novel, highly potent and in vivo active inhibitor of GABA transporter subtype 1 with anticonvulsant, anxiolytic, antidepressant and antinociceptive properties. Neuropharmacology 2017; 113:331-342. [DOI: 10.1016/j.neuropharm.2016.10.019] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Revised: 09/18/2016] [Accepted: 10/17/2016] [Indexed: 01/09/2023]
|
8
|
Obradović ALJ, Scarpa J, Osuru HP, Weaver JL, Park JY, Pathirathna S, Peterkin A, Lim Y, Jagodic MM, Todorovic SM, Jevtovic-Todorovic V. Silencing the α2 subunit of γ-aminobutyric acid type A receptors in rat dorsal root ganglia reveals its major role in antinociception posttraumatic nerve injury. Anesthesiology 2015; 123:654-67. [PMID: 26164299 PMCID: PMC4568754 DOI: 10.1097/aln.0000000000000767] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
BACKGROUND Neuropathic pain (NPP) is likely the result of repetitive high-frequency bursts of peripheral afferent activity leading to long-lasting changes in synaptic plasticity in the spinal dorsal horn. Drugs that promote γ-aminobutyric acid (GABA) activity in the dorsal horn provide partial relief of neuropathic symptoms. The authors examined how in vivo silencing of the GABA receptor type A (GABAA) α2 gene in dorsal root ganglia (DRG) controls NPP. METHODS After crush injury to the right sciatic nerve of female rats, the α2 GABAA antisense and mismatch oligodeoxynucleotides or NO-711 (a GABA uptake inhibitor) were applied to the L5 DRG. In vivo behavioral assessment of nociception was conducted before the injury and ensuing 10 days (n = 4 to 10). In vitro quantification of α2 GABAA protein and electrophysiological studies of GABAA currents were performed on acutely dissociated L5 DRG neurons at relevant time points (n = 6 to 14). RESULTS NPP postcrush injury of a sciatic nerve in adult female rats coincides with significant down-regulation of the α2 subunit expression in the ipsilateral DRG (approximately 30%). Selective down-regulation of α2 expression in DRGs significantly worsens mechanical (2.55 ± 0.75 to 5.16 ± 1.16) and thermal (7.97 ± 0.96 to 5.51 ± 0.75) hypersensitivity in crush-injured animals and causes development of significant mechanical (2.33 ± 0.40 to 5.00 ± 0.33) and thermal (10.80 ± 0.29 to 7.34 ± 0.81) hypersensitivity in sham animals (data shown as mean ± SD). Conversely, up-regulation of endogenous GABA via blockade of its uptake in DRG alleviates NPP. CONCLUSION The GABAA receptor in the DRG plays an important role in pathophysiology of NPP caused by sciatic nerve injury and represents promising target for novel pain therapies.
Collapse
Affiliation(s)
- Aleksandar LJ Obradović
- Department of Anesthesiology, University of Virginia Health System, Charlottesville, VA, USA
- Department of Physiology, University of Belgrade School of Pharmacy, Belgrade, Serbia
| | - Joseph Scarpa
- Department of Anesthesiology, University of Virginia Health System, Charlottesville, VA, USA
- Icahn Institute for Genomics and Multiscale Biology, Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Hari P Osuru
- Department of Anesthesiology, University of Virginia Health System, Charlottesville, VA, USA
| | - Janelle L Weaver
- Department of Anesthesiology, University of Virginia Health System, Charlottesville, VA, USA
| | - Ji-Yong Park
- Department of Anesthesiology, University of Virginia Health System, Charlottesville, VA, USA
- Department of Anesthesiology and Pain Medicine, College of Medicine, Korea University, Seoul, Republic of Korea
| | - Sriyani Pathirathna
- Department of Anesthesiology, University of Virginia Health System, Charlottesville, VA, USA
| | - Alexander Peterkin
- Department of Anesthesiology, University of Virginia Health System, Charlottesville, VA, USA
| | - Yunhee Lim
- Department of Anesthesiology, University of Virginia Health System, Charlottesville, VA, USA
- Department of Anesthesiology and Pain Medicine, Sanggye Paik Hospital, College of Medicine, Inje University, Seoul, Republic of Korea
| | - Miljenko M Jagodic
- Department of Anesthesiology, University of Virginia Health System, Charlottesville, VA, USA
| | - Slobodan M Todorovic
- Department of Anesthesiology, University of Virginia Health System, Charlottesville, VA, USA
- Department of Neuroscience, University of Virginia Health System, Charlottesville, VA, USA
| | - Vesna Jevtovic-Todorovic
- Department of Anesthesiology, University of Virginia Health System, Charlottesville, VA, USA
- Department of Neuroscience, University of Virginia Health System, Charlottesville, VA, USA
| |
Collapse
|
9
|
Yadav R, Yan X, Maixner DW, Gao M, Weng HR. Blocking the GABA transporter GAT-1 ameliorates spinal GABAergic disinhibition and neuropathic pain induced by paclitaxel. J Neurochem 2015; 133:857-69. [PMID: 25827582 DOI: 10.1111/jnc.13103] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 03/02/2015] [Accepted: 03/05/2015] [Indexed: 11/24/2022]
Abstract
Paclitaxel is a chemotherapeutic agent widely used for treating carcinomas. Patients receiving paclitaxel often develop neuropathic pain and have a reduced quality of life which hinders the use of this life-saving drug. In this study, we determined the role of GABA transporters in the genesis of paclitaxel-induced neuropathic pain using behavioral tests, electrophysiology, and biochemical techniques. We found that tonic GABA receptor activities in the spinal dorsal horn were reduced in rats with neuropathic pain induced by paclitaxel. In normal controls, tonic GABA receptor activities were mainly controlled by the GABA transporter GAT-1 but not GAT-3. In the spinal dorsal horn, GAT-1 was expressed at presynaptic terminals and astrocytes while GAT-3 was only expressed in astrocytes. In rats with paclitaxel-induced neuropathic pain, the protein expression of GAT-1 was increased while GAT-3 was decreased. This was concurrently associated with an increase in global GABA uptake. The paclitaxel-induced attenuation of GABAergic tonic inhibition was ameliorated by blocking GAT-1 but not GAT-3 transporters. Paclitaxel-induced neuropathic pain was significantly attenuated by the intrathecal injection of a GAT-1 inhibitor. These findings suggest that targeting GAT-1 transporters for reversing disinhibition in the spinal dorsal horn may be a useful approach for treating paclitaxel-induced neuropathic pain. Patients receiving paclitaxel for cancer therapy often develop neuropathic pain and have a reduced quality of life. In this study, we demonstrated that animals treated with paclitaxel develop neuropathic pain, have enhancements of GABA transporter-1 protein expression and global GABA uptake, as well as suppression of GABAergic tonic inhibition in the spinal dorsal horn. Pharmacological inhibition of GABA transporter-1 ameliorates the paclitaxel-induced suppression of GABAergic tonic inhibition and neuropathic pain. Thus, targeting GAT-1 transporters for reversing GABAergic disinhibition in the spinal dorsal horn could be a useful approach for treating paclitaxel-induced neuropathic pain.
Collapse
Affiliation(s)
- Ruchi Yadav
- Department of Pharmaceutical and Biomedical Sciences, The University of Georgia College of Pharmacy, Athens, Georgia, USA
| | - Xisheng Yan
- Department of Pharmaceutical and Biomedical Sciences, The University of Georgia College of Pharmacy, Athens, Georgia, USA.,Department of Cardiovascular Medicine, the Third Hospital of Wuhan, Wuhan, Hubei Province, China
| | - Dylan W Maixner
- Department of Pharmaceutical and Biomedical Sciences, The University of Georgia College of Pharmacy, Athens, Georgia, USA
| | - Mei Gao
- Department of Pharmaceutical and Biomedical Sciences, The University of Georgia College of Pharmacy, Athens, Georgia, USA
| | - Han-Rong Weng
- Department of Pharmaceutical and Biomedical Sciences, The University of Georgia College of Pharmacy, Athens, Georgia, USA
| |
Collapse
|
10
|
Thalamic δ-subunit containing GABAA receptors promote electrocortical signatures of deep non-REM sleep but do not mediate the effects of etomidate at the thalamus in vivo. J Neurosci 2015; 34:12253-66. [PMID: 25209268 DOI: 10.1523/jneurosci.0618-14.2014] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Extrasynaptic δ-subunits containing GABAA receptors (δGABAARs) are sensitive targets for several commonly used hypnotic agents and mediate tonic neuronal inhibition. δGABAARs are highly expressed within the thalamus and their activation promotes a switch from tonic to burst firing in vitro. Here we test two hypotheses in vivo. (1) Activation of thalamic δGABAARs will elicit electrocortical signatures consistent with widespread thalamocortical burst firing such as increased delta oscillations (1-4 Hz) and reciprocal changes in spindle-like oscillations (7-14 Hz). (2) These signatures will be recapitulated by the general anesthetic etomidate, if the electrocortical effects of etomidate at the thalamus are mediated by δGABAARs. Microperfusion of the δGABAAR-preferring agonist 4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridin-3-ol (THIP; 10 and 50 μM) into the ventrobasal complex produced significant effects on electrocortical activity in wild-type mice, but not in mice lacking δGABAARs (Gabrd(-/-)), i.e., the effects with THIP were dependent on δGABAARs. THIP (1) increased 1-4 Hz power in wakefulness and nonrapid-eye movement (NREM) sleep; (2) reduced spindle-like oscillations in NREM sleep; and (3) increased the speed of stable transitions into NREM sleep, indicating effects on state-space dynamics. In contrast, microperfusion of etomidate (10 and 30 μM) into the ventrobasal complex produced effects on electrocortical activity that were independent of δGABAARs, i.e., effects occurred in wild-type and Gabrd(-/-) mice. Etomidate (1) decreased 1-4 Hz power, increased 8-12 Hz, and/or 12-30 Hz power in all sleep-wake states; (2) increased spindle-like oscillations; and (3) increased REM sleep expression. These results indicate that thalamic δGABAARs promote electrocortical signatures of deep NREM sleep, but do not mediate the effects of etomidate at the thalamus in vivo.
Collapse
|
11
|
Sałat K, Podkowa A, Kowalczyk P, Kulig K, Dziubina A, Filipek B, Librowski T. Anticonvulsant active inhibitor of GABA transporter subtype 1, tiagabine, with activity in mouse models of anxiety, pain and depression. Pharmacol Rep 2014; 67:465-72. [PMID: 25933955 DOI: 10.1016/j.pharep.2014.11.003] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Revised: 10/21/2014] [Accepted: 11/12/2014] [Indexed: 10/24/2022]
Abstract
BACKGROUND Tiagabine, a selective inhibitor of GABA transporter subtype 1 is used as an add-on therapy of partial seizures in humans but its mechanism of action suggests other potential medical indications for this drug. In this research we assess its pharmacological activity in several screening models of seizures, pain, anxiety and depression in mice. METHODS For pharmacological tests tiagabine was administered intraperitoneally 60 min before the assay. Behavioral tests were performed using models of chemically and electrically induced seizures, thermal acute pain and formalin-induced tonic pain. Anxiolytic-like properties were evaluated using the four plate test and the elevated plus maze test. Antidepressant-like activity was assessed in the forced swim test. In addition, to exclude false positive results in these assays, the influence of tiagabine on animals' locomotor activity and motor coordination was investigated, too. RESULTS Tiagabine demonstrated anticonvulsant properties in chemically induced seizures (pentylenetetrazole and pilocarpine seizures). At the dose of 100mg/kg it also elevated the seizure threshold for electrically induced seizures by 31.6% (p<0.01), but it had no activity in the maximal electroshock seizure test. Tiagabine showed anxiolytic-like and antidepressant-like effects. Although it apparently reduced animals' nociceptive responses in pain tests, these activities rather resulted from its sedative and motor-impairing properties demonstrated in the locomotor activity and the rotarod tests, respectively. CONCLUSIONS The results obtained in the present study suggest that tiagabine, apart its anticonvulsant effect, has anxiolytic-like, sedative and antidepressant-like properties. In view of this, it can be potentially used in the treatment of anxiety and mood disorders.
Collapse
Affiliation(s)
- Kinga Sałat
- Department of Pharmacodynamics, Jagiellonian University, Medical College, Kraków, Poland.
| | - Adrian Podkowa
- Department of Pharmacodynamics, Jagiellonian University, Medical College, Kraków, Poland
| | - Paula Kowalczyk
- Department of Physicochemical Drug Analysis, Chair of Pharmaceutical Chemistry, Jagiellonian University, Medical College, Kraków, Poland
| | - Katarzyna Kulig
- Department of Physicochemical Drug Analysis, Chair of Pharmaceutical Chemistry, Jagiellonian University, Medical College, Kraków, Poland
| | - Anna Dziubina
- Department of Pharmacodynamics, Jagiellonian University, Medical College, Kraków, Poland
| | - Barbara Filipek
- Department of Pharmacodynamics, Jagiellonian University, Medical College, Kraków, Poland
| | - Tadeusz Librowski
- Department of Radioligands, Jagiellonian University, Medical College, Kraków, Poland
| |
Collapse
|
12
|
Sałat K, Więckowska A, Więckowski K, Höfner GC, Kamiński J, Wanner KT, Malawska B, Filipek B, Kulig K. Synthesis and pharmacological properties of new GABA uptake inhibitors. Pharmacol Rep 2013; 64:817-33. [PMID: 23087134 DOI: 10.1016/s1734-1140(12)70877-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2011] [Revised: 04/05/2012] [Indexed: 12/01/2022]
Abstract
BACKGROUND γ-Aminobutanoic acid (GABA) is the principal inhibitory neurotransmitter in the mammalian central nervous system. The identification and subsequent development of the GABA transport inhibitors which enhance the GABA-ergic transmission has shown the important role that GABA transporters play in the control of numerous functions of the nervous system. Compounds which inhibit GABA uptake are used as antiepileptic drugs (tiagabine - a selective GAT1 inhibitor), they are also being investigated for other indications, including treatment of psychosis, general anxiety, sleep disorders, drug addiction or acute and chronic pain. METHODS In this paper, the synthesis of 2-substituted-4-(1,3-dioxoisoindolin-2-ylo)-butanamides and 2-substituted-4-aminobutanoic acids derivatives is described. These compounds were tested in vitro for their ability to inhibit GABA uptake. The inhibitory potency towards murine plasma membrane GABA transporters (mGAT1-4) was performed as [(3)H]GABA uptake assay based on stably transfected HEK cells. Compound 18, which demonstrated the highest affinity for mGAT1-4 (pIC(50) ranged from 4.42 for mGAT1 to 5.07 for mGAT3), was additionally investigated in several behavioral tests in mice. RESULTS Compound 18 increased the locomotor activity (14-38%) and had anxiolytic-like properties in the four-plate test (ED(50) = 9.3 mg/kg). It did not show analgesic activity in acute pain model, namely the hot plate test, however, it was antinociceptive in the acetic acid-induced writhing test (ED(50) = 15.3 mg/kg) and in the formalin model of tonic pain. In the latter assay, it diminished nocifensive behavior in both phases and in the first (neurogenic) phase of this test the obtained ED(50) value (5.3 mg/kg) was similar to morphine (3.0 mg/kg). CONCLUSION Compound 18 exhibited significant anxiolytic-like properties and was antinociceptive in some models of pain in mice. Moreover, it did not impair animals' motor coordination in the chimney test. Some of the described pharmacological activities of compound 18 can be partly explained based on its affinity for plasma membrane GABA transporters.
Collapse
Affiliation(s)
- Kinga Sałat
- Department of Physicochemical Drug Analysis, Jagiellonian University, Medical College, Kraków, Poland
| | | | | | | | | | | | | | | | | |
Collapse
|
13
|
Zeilhofer HU, Benke D, Yevenes GE. Chronic pain states: pharmacological strategies to restore diminished inhibitory spinal pain control. Annu Rev Pharmacol Toxicol 2012; 52:111-33. [PMID: 21854227 DOI: 10.1146/annurev-pharmtox-010611-134636] [Citation(s) in RCA: 116] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Potentially noxious stimuli are sensed by specialized nerve cells named nociceptors, which convey nociceptive signals from peripheral tissues to the central nervous system. The spinal dorsal horn and the trigeminal nucleus serve as first relay stations for incoming nociceptive signals. At these sites, nociceptor terminals contact a local neuronal network consisting of excitatory and inhibitory interneurons as well as of projection neurons. Blockade of neuronal inhibition in this network causes an increased sensitivity to noxious stimuli (hyperalgesia), painful sensations occurring after activation of non-nociceptive fibers (allodynia), and spontaneous pain felt in the absence of any sensory stimulation. It thus mimics the major characteristics of chronic pain states. Diminished inhibitory pain control in the spinal dorsal horn occurs naturally, e.g., through changes in the function of inhibitory neurotransmitter receptors or through altered chloride homeo-stasis in the course of inflammation or nerve damage. This review summarizes our current knowledge about endogenous mechanisms leading to diminished spinal pain control and discusses possible ways that could restore proper inhibition through facilitation of fast inhibitory neurotransmission.
Collapse
Affiliation(s)
- Hanns Ulrich Zeilhofer
- Institute of Pharmacology and Toxicology, University of Zurich, CH-8057 Zurich, Switzerland.
| | | | | |
Collapse
|
14
|
Analgesic and anticonvulsant activity of new derivatives of 2-substituted 4-hydroxybutanamides in mice. Pharmacol Rep 2012; 64:102-12. [DOI: 10.1016/s1734-1140(12)70736-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2011] [Revised: 09/15/2011] [Indexed: 01/18/2023]
|
15
|
Abstract
GABA, the principal inhibitory neurotransmitter in the cerebral cortex, maintains the inhibitory tone that counterbalances neuronal excitation. The identification and subsequent development of GABA-transport inhibitors has shown the important role that GABA transporters play in the control of the CNS. To date, four GABA transporters have been cloned (GAT1-4). Compounds that inhibit GABA uptake are targets for epilepsy treatment. Currently, they are also being investigated for other possible indications such as the treatment of psychosis, general anxiety and sleep disorders, drug addiction, acute and chronic pain. These and other issues are discussed in this article.
Collapse
|
16
|
Analgesic effect of intrathecally γ-aminobutyric acid transporter-1 inhibitor NO-711 administrating on neuropathic pain in rats. Neurosci Lett 2011; 494:6-9. [DOI: 10.1016/j.neulet.2011.02.028] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Revised: 02/11/2011] [Accepted: 02/11/2011] [Indexed: 10/18/2022]
|
17
|
Whitehead KJ, Smith CGS, Delaney SA, Curnow SJ, Salmon M, Hughes JP, Chessell IP. Dynamic regulation of spinal pro-inflammatory cytokine release in the rat in vivo following peripheral nerve injury. Brain Behav Immun 2010; 24:569-76. [PMID: 20035858 DOI: 10.1016/j.bbi.2009.12.007] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2009] [Revised: 12/16/2009] [Accepted: 12/16/2009] [Indexed: 01/02/2023] Open
Abstract
Spinal release of cytokines may play a critical role in the maladapted nociceptive signaling underlying chronic pain states. In order to investigate this biology, we have developed a novel 'high flux' intrathecal microdialysis approach in combination with multiplex bead-based immunoassay technology to concurrently monitor the spinal release of interleukin (IL)-1beta, IL-6 and tumour necrosis factor (TNF)alpha in rats with unilateral sciatic nerve chronic constriction injury (CCI). Intrathecal microdialysis was performed under isoflurane/N(2)O anaesthesia in rats with confirmed mechanical hypersensitivity. In a first study, C-fiber strength electrical stimulation of the operated nerve in neuropathic rats was found to evoke a dramatic increase in IL-1beta efflux ( approximately 15-fold) that was significantly greater than that observed in the sham-operated group. Spinal IL-6 efflux was also responsive to primary afferent stimulation, whereas TNFalpha was not. In a second study, treatment with the glial inhibitor propentofylline for 7days normalized CCI-induced mechanical hypersensitivity. In the same animals, this treatment also significantly reduced intrathecal IL-1beta, IL-6 and TNFalpha and prevented afferent stimulation-evoked cytokine release of both IL-1beta and IL-6. These results provide support for glia as the source of the majority of intrathecal IL-1beta, IL-6 and TNFalpha that accompanies mechanical hypersensitivity in the CCI rat. Moreover, our studies demonstrate the ability of a neurone-glia signaling mechanism to dynamically modulate this release and support a role of spinal IL-1beta in the phasic transmission of abnormal pain signals.
Collapse
Affiliation(s)
- K J Whitehead
- Pain Signalling Group, Neuropharmacology and Neurobiology Section, School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
| | | | | | | | | | | | | |
Collapse
|
18
|
Pinto-Ribeiro F, Moreira V, Pêgo JM, Leão P, Almeida A, Sousa N. Antinociception induced by chronic glucocorticoid treatment is correlated to local modulation of spinal neurotransmitter content. Mol Pain 2009; 5:41. [PMID: 19630968 PMCID: PMC2727498 DOI: 10.1186/1744-8069-5-41] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2009] [Accepted: 07/24/2009] [Indexed: 12/26/2022] Open
Abstract
Background While acute effects of stress on pain are well described, those produced by chronic stress are still a matter of dispute. Previously we demonstrated that chronic unpredictable stress results in antinociception in the tail-flick test, an effect that is mediated by increased levels of corticosteroids. In the present study, we evaluated nociception in rats after chronic treatment with corticosterone (CORT) and dexamethasone (DEX) in order to discriminate the role of each type of corticosteroid receptors in antinociception. Results Both experimental groups exhibited a pronounced antinociceptive effect after three weeks of treatment when compared to controls (CONT); however, at four weeks the pain threshold in CORT-treated animals returned to basal levels whereas in DEX-treated rats antinociception was maintained. In order to assess if these differences are associated with altered expression of neuropeptides involved in nociceptive transmission we evaluated the density of substance P (SP), calcitonin gene-related peptide (CGRP), somatostatin (SS) and B2-γ-aminobutiric acid receptors (GABAB2) expression in the spinal dorsal horn using light density measurements and stereological techniques. After three weeks of treatment the expression of CGRP in the superficial dorsal horn was significantly decreased in both CORT and DEX groups, while GABAB2 was significantly increased; the levels of SP for both experimental groups remained unchanged at this point. At 4 weeks, CGRP and SP are reduced in DEX-treated animals and GABAB2 unchanged, but all changes were restored to CONT levels in CORT-treated animals. The expression of SS remained unaltered throughout the experimental period. Conclusion These data indicate that corticosteroids modulate nociception since chronic corticosteroid treatment alters the expression of neuropeptides involved in nociceptive transmission at the spinal cord level. As previously observed in some supraspinal areas, the exclusive GR activation resulted in more profound and sustained behavioural and neurochemical changes, than the one observed with a mixed ligand of corticosteroid receptors. These results might be of relevance for the pharmacological management of certain types of chronic pain, in which corticosteroids are used as adjuvant analgesics.
Collapse
Affiliation(s)
- Filipa Pinto-Ribeiro
- Life and Health Science Research Institute, School of Health Sciences, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
| | | | | | | | | | | |
Collapse
|
19
|
Daemen MA, Hoogland G, Cijntje JM, Spincemaille GH. Upregulation of the GABA-transporter GAT-1 in the spinal cord contributes to pain behaviour in experimental neuropathy. Neurosci Lett 2008; 444:112-5. [DOI: 10.1016/j.neulet.2008.08.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2008] [Revised: 07/23/2008] [Accepted: 08/01/2008] [Indexed: 10/21/2022]
|