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Salmanzadeh H, Halliwell RF. Antiseizure properties of fenamate NSAIDs determined in mature human stem-cell derived neuroglial circuits. Front Pharmacol 2024; 15:1385523. [PMID: 38828453 PMCID: PMC11141243 DOI: 10.3389/fphar.2024.1385523] [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: 02/13/2024] [Accepted: 04/30/2024] [Indexed: 06/05/2024] Open
Abstract
Repeated and uncontrolled seizures in epilepsy result in brain cell loss and neural inflammation. Current anticonvulsants primarily target ion channels and receptors implicated in seizure activity. Identification of neurotherapeutics that can inhibit epileptiform activity and reduce inflammation in the brain may offer significant benefits in the long-term management of epilepsy. Fenamates are unique because they are both non-steroidal anti-inflammatory drugs (NSAIDs) and highly subunit selective modulators of GABAA receptors. In the current study we have investigated the hypothesis that fenamates have antiseizure properties using mature human stem cell-derived neuro-glia cell cultures, maintained in long-term culture, and previously shown to be sensitive to first, second and third generation antiepileptics. Mefenamic acid, flufenamic acid, meclofenamic acid, niflumic acid, and tolfenamic acid (each tested at 10-100 μM) attenuated 4-aminopyridine (4-AP, 100 μM) evoked epileptiform activity in a dose-dependent fashion. These actions were as effective diazepam (3-30 μM) and up to 200 times more potent than phenobarbital (300-1,000 μM). The low (micromolar) concentrations of fenamates that inhibited 4-AP evoked epileptiform activity correspond to those reported to potentiate GABAA receptor function. In contrast, the fenamates had no effect on neural spike amplitudes, indicating that their antiseizure actions did not result from inhibition of sodium-channels. The antiseizure actions of fenamates were also not replicated by either of the two non-fenamate NSAIDs, ibuprofen (10-100 μM) or indomethacin (10-100 μM), indicating that inhibition of cyclooxygenases is not the mechanism through which fenamates have anticonvulsant properties. This study therefore shows for the first time, using functionally mature human stem cell-derived neuroglial circuits, that fenamate NSAIDs have powerful antiseizure actions independent of, and in addition to their well-established anti-inflammatory properties, suggesting these drugs may provide a novel insight and new approach to the treatment of epilepsy in the future.
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Affiliation(s)
| | - Robert F. Halliwell
- Thomas J. Long School of Pharmacy, University of the Pacific, Stockton, CA, United States
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2
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Halliwell RF, Salmanzadeh H, Coyne L, Cao WS. An Electrophysiological and Pharmacological Study of the Properties of Human iPSC-Derived Neurons for Drug Discovery. Cells 2021; 10:cells10081953. [PMID: 34440722 PMCID: PMC8395001 DOI: 10.3390/cells10081953] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 07/28/2021] [Accepted: 07/29/2021] [Indexed: 01/01/2023] Open
Abstract
Human stem cell-derived neurons are increasingly considered powerful models in drug discovery and disease modeling, despite limited characterization of their molecular properties. Here, we have conducted a detailed study of the properties of a commercial human induced Pluripotent Stem Cell (iPSC)-derived neuron line, iCell [GABA] neurons, maintained for up to 3 months in vitro. We confirmed that iCell neurons display neurite outgrowth within 24 h of plating and label for the pan-neuronal marker, βIII tubulin within the first week. Our multi-electrode array (MEA) recordings clearly showed neurons generated spontaneous, spike-like activity within 2 days of plating, which peaked at one week, and rapidly decreased over the second week to remain at low levels up to one month. Extracellularly recorded spikes were reversibly inhibited by tetrodotoxin. Patch-clamp experiments showed that iCell neurons generated spontaneous action potentials and expressed voltage-gated Na and K channels with membrane capacitances, resistances and membrane potentials that are consistent with native neurons. Our single neuron recordings revealed that reduced spiking observed in the MEA after the first week results from development of a dominant inhibitory tone from GABAergic neuron circuit maturation. GABA evoked concentration-dependent currents that were inhibited by the convulsants, bicuculline and picrotoxin, and potentiated by the positive allosteric modulators, diazepam, chlordiazepoxide, phenobarbital, allopregnanolone and mefenamic acid, consistent with native neuronal GABAA receptors. We also show that glycine evoked robust concentration-dependent currents that were inhibited by the neurotoxin, strychnine. Glutamate, AMPA, Kainate and NMDA each evoked concentration-dependent currents in iCell neurons that were blocked by their selective antagonists, consistent with the expression of ionotropic glutamate receptors. The NMDA currents required the presence of the co-agonist glycine and were blocked in a highly voltage-dependent manner by Mg2+ consistent with the properties of native neuronal NMDA receptors. Together, our data suggest that such human iPSC-derived neurons may have significant value in drug discovery and development and may eventually largely replace the need for animal tissues in human biomedical research.
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Ayoub R, Jarrar Q, Ali D, Moshawih S, Jarrar Y, Hakim M, Zakaria Z. Synthesis of Novel Esters of Mefenamic Acid with Pronounced Anti-nociceptive Effects and a Proposed Activity on GABA , Opioid and Glutamate Receptors. Eur J Pharm Sci 2021; 163:105865. [PMID: 33979659 DOI: 10.1016/j.ejps.2021.105865] [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: 01/13/2021] [Revised: 04/10/2021] [Accepted: 04/26/2021] [Indexed: 10/21/2022]
Abstract
BACKGROUND Mefenamic acid (MFA), a commonly prescribed non-steroidal anti-inflammatory drug (NSAID), possesses a greater risk of dose-related central nervous system (CNS) toxicity than other NSAIDs. In this study, α-tocopherol and α-tocopherol acetate were selected as prodrug moieties for MFA in an attempt to reduce the CNS toxicity and enhance the therapeutic efficacy. METHOD α-tocopherol monoester of MFA (TMMA) and α-tocopherol di-ester of MFA (TDMA) were synthesized by esterification reaction and were subjected to various in vivo characterizations. RESULTS Masking of the carboxylate group of MFA with the proposed pro-moieties significantly (p<0.05) delayed the onset of tonic-clonic seizure in mice. Besides, the intraperitoneal administration of TMMA and TDMA in mice produced significantly (p<0.05) stronger anti-inflammatory effects in the carrageenan-induced paw edema test and greater anti-nociceptive effect in the acetic acid-induced writhing test than MFA at an equimolar dose of 20 mg/kg. Treatment with TMMA and TDMA caused a significant (p<0.05) inhibition of pain at 1st and 2nd phases of formalin-induced licking test in mice, whereas treatment with MFA inhibited the 2nd phase only. Pretreatment with naloxone and flumazenil significantly (p<0.05) reversed the anti-nociceptive effect of MFA, TMMA and TDMA in the acetic acid-induced writhing test. In addition, treatment with TMMA and TDMA caused significantly (p<0.05) a higher inhibition of pain in the glutamate-induced licking response in mice than MFA. CONCLUSION Masking the carboxylate moiety of MFA by α-tocopherol and α-tocopherol acetate has a great potential for reducing CNS toxicity, enhancing the therapeutic efficacy and altering the mode of anti-nociceptive action.
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Affiliation(s)
- Rami Ayoub
- Department of applied pharmaceutical sciences and clinical pharmacy, Faculty of pharmacy, Isra University, Amman, Jordan
| | - Qais Jarrar
- Department of applied pharmaceutical sciences and clinical pharmacy, Faculty of pharmacy, Isra University, Amman, Jordan.
| | - Dalia Ali
- Department of applied pharmaceutical sciences and clinical pharmacy, Faculty of pharmacy, Isra University, Amman, Jordan
| | - Said Moshawih
- PAPRSB Institute of Health Sciences, Universiti Brunei Darussalam, Gadong, Brunei Darussalam
| | - Yazun Jarrar
- Department of Pharmaceutical Science, Faculty of Pharmacy, Al-Zaytoonah University of Jordan, Amman, Jordan
| | - Muhammad Hakim
- Department of Biomedical Science, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
| | - Zainul Zakaria
- Department of Biomedical Science, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
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Rossokhin A. The general anesthetic etomidate and fenamate mefenamic acid oppositely affect GABA AR and GlyR: a structural explanation. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2020; 49:591-607. [PMID: 32940715 DOI: 10.1007/s00249-020-01464-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Revised: 09/03/2020] [Accepted: 09/07/2020] [Indexed: 12/19/2022]
Abstract
GABA and glycine act as inhibitory neurotransmitters in the CNS. Inhibitory neurotransmission is mediated via activation of ionotropic GABAA and glycine receptors. We used a modeling approach to explain the opposite effects of the general anesthetic etomidate (ETM) and fenamate mefenamic acid (MFA) on GABA- and glycine-activated currents recorded in isolated cerebellar Purkinje cells and hippocampal pyramidal neurons, respectively. These drugs potentiated GABAARs but blocked GlyRs. We built a homology model of α1β GlyR based on the cryo-EM structure of open α1 GlyR, used the α1β3γ2 GABAAR structure from the PDB, and applied Monte-Carlo energy minimization to optimize models of receptors and ligand-receptor complexes. In silico docking suggests that ETM/MFA bind at the transmembrane β( +)/α( -) intersubunit interface in GABAAR. Our models predict that the bulky side chain of the highly conserved Arg19' residue at the plus interface side wedges the interface and maintains the conducting receptor state. We hypothesized that MFA/ETM binding at the β( +)/α( -) interface leads to prolongation of receptor life-time in the open state. Having analyzed different GABAAR and GlyR structures available in the PDB, we found that mutual arrangement of the Arg19' and Gln-26' side chains at the plus and minus interface sides, respectively, plays an important role when the receptor switches from the open to closed state. We show that this process is accompanied by narrowing of the intersubunit interfaces, leading to extrusion of the Arg19' side chain from the interface. Our models allow us to explain the lack of GlyR potentiation in our electrophysiological experiments.
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Sirenko O, Parham F, Dea S, Sodhi N, Biesmans S, Mora-Castilla S, Ryan K, Behl M, Chandy G, Crittenden C, Vargas-Hurlston S, Guicherit O, Gordon R, Zanella F, Carromeu C. Functional and Mechanistic Neurotoxicity Profiling Using Human iPSC-Derived Neural 3D Cultures. Toxicol Sci 2019; 167:58-76. [PMID: 30169818 DOI: 10.1093/toxsci/kfy218] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Neurological disorders affect millions of people worldwide and appear to be on the rise. Whereas the reason for this increase remains unknown, environmental factors are a suspected contributor. Hence, there is an urgent need to develop more complex, biologically relevant, and predictive in vitro assays to screen larger sets of compounds with the potential for neurotoxicity. Here, we employed a human induced pluripotent stem cell (iPSC)-based 3D neural platform composed of mature cortical neurons and astrocytes as a model for this purpose. The iPSC-derived human 3D cortical neuron/astrocyte co-cultures (3D neural cultures) present spontaneous synchronized, readily detectable calcium oscillations. This advanced neural platform was optimized for high-throughput screening in 384-well plates and displays highly consistent, functional performance across different wells and plates. Characterization of oscillation profiles in 3D neural cultures was performed through multi-parametric analysis that included the calcium oscillation rate and peak width, amplitude, and waveform irregularities. Cellular and mitochondrial toxicity were assessed by high-content imaging. For assay characterization, we used a set of neuromodulators with known mechanisms of action. We then explored the neurotoxic profile of a library of 87 compounds that included pharmaceutical drugs, pesticides, flame retardants, and other chemicals. Our results demonstrated that 57% of the tested compounds exhibited effects in the assay. The compounds were then ranked according to their effective concentrations based on in vitro activity. Our results show that a human iPSC-derived 3D neural culture assay platform is a promising biologically relevant tool to assess the neurotoxic potential of drugs and environmental toxicants.
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Affiliation(s)
| | - Frederick Parham
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina
| | - Steven Dea
- StemoniX, Inc, Maple Grove, Minnesota 55311
| | - Neha Sodhi
- StemoniX, Inc, Maple Grove, Minnesota 55311
| | | | | | - Kristen Ryan
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina
| | - Mamta Behl
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina
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Rossokhin AV, Sharonova IN, Dvorzhak A, Bukanova JV, Skrebitsky VG. The mechanisms of potentiation and inhibition of GABA A receptors by non-steroidal anti-inflammatory drugs, mefenamic and niflumic acids. Neuropharmacology 2019; 160:107795. [PMID: 31560908 DOI: 10.1016/j.neuropharm.2019.107795] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 09/02/2019] [Accepted: 09/23/2019] [Indexed: 11/27/2022]
Abstract
Fenamates mefanamic and niflumic acids (MFA and NFA) induced dual potentiating and inhibitory effects on GABA currents recorded in isolated cerebellar Purkinje cells using the whole-cell patch-clamp and fast-application techniques. Regardless of the concentration, both drugs induced a pronounced prolongation of the current response. We demonstrated that the same concentration of drugs can produce both potentiating and inhibitory effects, depending on the GABA concentration, which indicates that both processes take place simultaneously and the net effect depends on the concentrations of both the agonist and fenamate. We found that the NFA-induced block is strongly voltage-dependent. The Woodhull analysis of the block suggests that NFA has two binding sites in the pore - shallow and deep. We built a homology model of the open GABAAR based on the cryo-EM structure of the open α1 GlyR and applied Monte-Carlo energy minimization to optimize the ligand-receptor complexes. A systematic search for MFA/NFA binding sites in the GABAAR pore revealed the existence of two sites, the location of which coincides well with predictions of the Woodhull model. In silico docking suggests that two fenamate molecules are necessary to occlude the pore. We showed that MFA, acting as a PAM, competes with an intravenous anesthetic etomidate for a common binding site. We built structural models of MFA and NFA binding at the transmembrane β(+)/α(-) intersubunit interface. We suggested a hypothesis on the molecular mechanism underlying the prolongation of the receptor lifetime in open state after MFA/NFA binding and β subunit specificity of the fenamate potentiation.
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Affiliation(s)
| | | | - Anton Dvorzhak
- Charité-Universitätsmedizin, Neuroscience Research Center, Berlin, Germany
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7
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Multiple actions of fenamates and other nonsteroidal anti-inflammatory drugs on GABAA receptors. Eur J Pharmacol 2019; 853:247-255. [DOI: 10.1016/j.ejphar.2019.03.039] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 03/18/2019] [Accepted: 03/22/2019] [Indexed: 01/02/2023]
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Khansari PS, Halliwell RF. Mechanisms Underlying Neuroprotection by the NSAID Mefenamic Acid in an Experimental Model of Stroke. Front Neurosci 2019; 13:64. [PMID: 30792624 PMCID: PMC6374636 DOI: 10.3389/fnins.2019.00064] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Accepted: 01/22/2019] [Indexed: 01/07/2023] Open
Abstract
Stroke is a devastating neurological event with limited treatment opportunities. Recent advances in understanding the underlying pathogenesis of cerebral ischemia support the involvement of multiple biochemical pathways in the development of the ischemic damage. Fenamates are classical non-steroidal anti-inflammatory drugs but they are also highly subunit-selective modulators of GABAA receptors, activators of IKS potassium channels and antagonists of non-selective cation channels and the NLRP3 inflammosome. In the present study we investigated the effect of mefenamic acid (MFA) in a rodent model of ischemic stroke and then addressed the underlying pharmacological mechanisms in vitro for its actions in vivo. The efficacy of MFA in reducing ischemic damage was evaluated in adult male Wistar rats subjected to a 2-h middle cerebral artery occlusion. Intracerebroventricular (ICV) infusion of MFA (0.5 or 1 mg/kg) for 24 h, significantly reduced the infarct volume and the total ischemic brain damage. In vitro, the fenamates, MFA, meclofenamic acid, niflumic acid, and flufenamic acid each reduced glutamate-evoked excitotoxicity in cultured embryonic rat hippocampal neurons supporting the idea that this is a drug class action. In contrast the non-fenamate NSAIDs, ibuprofen and indomethacin did not reduce excitotoxicity in vitro indicating that neuroprotection by MFA was not dependent upon anti-inflammatory actions. Co-application of MFA (100 μM) with either of the GABAA antagonists picrotoxin (100 μM) or bicuculline (10 μM) or the potassium channel blocker tetraethylammonium (30 mM) did not prevent neuroprotection with MFA, suggesting that the actions of MFA also do not depend on GABAA receptor modulation or potassium channel activation. These new findings indicate that fenamates may be valuable in the adjunctive treatment of ischemic stroke.
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Affiliation(s)
- Parto S Khansari
- School of Pharmacy and Pharmaceutical Sciences, Stony Brook University, Stony Brook, NY, United States
| | - Robert F Halliwell
- Thomas J. Long School of Pharmacy and Health Sciences, University of the Pacific, Stockton, CA, United States
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9
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Landucci E, Llorente IL, Anuncibay-Soto B, Pellegrini-Giampietro DE, Fernández-López A. Bicuculline Reverts the Neuroprotective Effects of Meloxicam in an Oxygen and Glucose Deprivation (OGD) Model of Organotypic Hippocampal Slice Cultures. Neuroscience 2018; 386:68-78. [PMID: 29949743 DOI: 10.1016/j.neuroscience.2018.06.024] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2018] [Revised: 05/25/2018] [Accepted: 06/18/2018] [Indexed: 01/17/2023]
Abstract
We previously demonstrated that the non-steroidal anti-inflammatory agent meloxicam has neuroprotective effects in an oxygen and glucose deprivation model (OGD) of rat organotypic hippocampal slice cultures. We wondered if GABAergic transmission changed the neuroprotective effects of meloxicam and if meloxicam was able to modulate endoplasmic reticulum stress (ER stress) in this model. Mortality was measured using propidium iodide. Western blot assays were performed to measure levels of cleaved and non-cleaved caspase-3 to quantify apoptosis, while levels of GRP78, GRP94 and phosphorylated eIF2α were used to detect unfolded protein response (UPR). Transcript levels of GRP78, GRP94 and GABAergic receptor α, β, and γ subunits were measured by real-time quantitative polymerase chain reaction (qPCR). In the present study, we show that the presence of meloxicam in a 30 min OGD assay, followed by 24 h of normoxic conditions, presented an antiapoptotic effect. The simultaneous presence of the GABAA receptor antagonist, bicuculline, in combination with meloxicam blocked the neuroprotective effect provided by the latter. However, in light of its effects on caspase 3 and PARP, bicuculline did not seem to promote the apoptotic pathway. Our results also showed that meloxicam modified the unfolded protein response (UPR), as well as the transcriptional response of different genes, including the GABAA receptor, alpha1, beta3 and gamma2 subunits. We concluded that meloxicam has a neuroprotective anti-apoptotic action, is able to enhance the UPR independently of the systemic anti-inflammatory response and its neuroprotective effect can be inhibited by blocking GABAA receptors.
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Affiliation(s)
- Elisa Landucci
- Sezione di Farmacologia Clinica e Oncologia, Dipartimento di Scienze della Salute, Università di Firenze, Viale Pieraccini 6, 50139 Firenze, Italy.
| | - Irene L Llorente
- Neurology Department, David Geffen School of Medicine, University of California, Los Angeles, USA.
| | - Berta Anuncibay-Soto
- Área de Biología Celular, Instituto de Biomedicina, Universidad de León, 24071 León, Spain; Neural Therapies SL, Edificio Institutos de Investigación, Local B14, Universidad de León, 24071 León, Spain.
| | - Domenico E Pellegrini-Giampietro
- Sezione di Farmacologia Clinica e Oncologia, Dipartimento di Scienze della Salute, Università di Firenze, Viale Pieraccini 6, 50139 Firenze, Italy.
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Rajesh V, Mridhulmohan M, Jayaseelan S, Sivakumar P, Ganesan V. Mefenamic Acid Attenuates Chronic Alcohol Induced Cognitive Impairment in Zebrafish: Possible Role of Cholinergic Pathway. Neurochem Res 2018; 43:1392-1404. [PMID: 29796737 DOI: 10.1007/s11064-018-2554-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 04/20/2018] [Accepted: 05/17/2018] [Indexed: 11/29/2022]
Abstract
Based on the scientific evidence supporting the neuroinflammatory response contributes the cognitive impairment associated with chronic alcoholism and the neuroprotective actions of mefenamic acid with reversal of memory loss and brain inflammation in mice, this study was designed to evaluate the effect of mefenamic acid against chronic alcohol induced cognitive impairment in zebrafish model. Zebrafish were grouped and subjected to normal behavioral analysis in light-dark chamber for 10 days. The preference to dark compartment was noted in zebrafish. Zebrafish were grouped and exposed to escalating doses of alcohol for 28 days with and without mefenamic acid exposure (100 and 200 µg/L) and subjected to a fear conditioning passive avoidance task from day 13 of 28. The cognitive evaluation was performed for 10 days and the brain tissue was isolated to estimate acetylcholinesterase activity. In cognitive evaluation study, the normal zebrafish retained the memory of the learned task and avoided the dark. The alcohol exposed zebrafish showed impairment in retaining the memory of learned task. Mefenamic acid exposed zebrafish showed a significant protection against cognitive impairment caused by alcohol and retained the memory of learned task with a significant decrease in AChE activity in brain homogenate compared to alcohol exposed zebrafish. The results of this study suggest that the memory enhancing activity of mefenamic acid might be due to activation of cholinergic transmission that has protected neuroinflammatory and neurodegenerative conditions caused by alcohol.
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Affiliation(s)
- Venugopalan Rajesh
- Department of Pharmacology, The Erode College of Pharmacy, Veppampalayam, Vallipurathampalayam (Po), Erode, Tamil Nadu, 638112, India.
| | - Mohanan Mridhulmohan
- Department of Pharmacology, Devaki Amma Memorial College of Pharmacy, Malappuram District, Chelembra, Kerala, 673634, India
| | - Subramanian Jayaseelan
- Department of Pharmaceutical Analysis, The Erode College of Pharmacy, Veppampalayam, Vallipurathampalayam (Po), Erode, Tamil Nadu, 638112, India
| | - Palanivel Sivakumar
- Department of Pharmaceutical chemistry, The Erode College of Pharmacy, Veppampalayam, Vallipurathampalayam (Po), Erode, Tamil Nadu, 638112, India
| | - Vellaiyachamy Ganesan
- Department of Pharmaceutics, The Erode College of Pharmacy, Veppampalayam, Vallipurathampalayam (Po), Erode, Tamil Nadu, 638112, India
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Surov AO, Voronin AP, Vener MV, Churakov AV, Perlovich GL. Specific features of supramolecular organisation and hydrogen bonding in proline cocrystals: a case study of fenamates and diclofenac. CrystEngComm 2018. [DOI: 10.1039/c8ce01458b] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
New zwitterionic cocrystals of fenamate drugs and diclofenac with the naturally occurring amino acid l-proline have been obtained and thoroughly characterised by a variety of experimental and theoretical techniques.
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Affiliation(s)
- Artem O. Surov
- G.A. Krestov Institute of Solution Chemistry of the Russian Academy of Sciences
- 153045 Ivanovo
- Russia
| | - Alexander P. Voronin
- G.A. Krestov Institute of Solution Chemistry of the Russian Academy of Sciences
- 153045 Ivanovo
- Russia
| | | | - Andrei V. Churakov
- N.S. Kurnakov Institute of General and Inorganic Chemistry of the Russian Academy of Sciences
- Moscow
- Russia
| | - German L. Perlovich
- G.A. Krestov Institute of Solution Chemistry of the Russian Academy of Sciences
- 153045 Ivanovo
- Russia
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12
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Willebrords J, Maes M, Crespo Yanguas S, Vinken M. Inhibitors of connexin and pannexin channels as potential therapeutics. Pharmacol Ther 2017; 180:144-160. [PMID: 28720428 PMCID: PMC5802387 DOI: 10.1016/j.pharmthera.2017.07.001] [Citation(s) in RCA: 106] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
While gap junctions support the exchange of a number of molecules between neighboring cells, connexin hemichannels provide communication between the cytosol and the extracellular environment of an individual cell. The latter equally holds true for channels composed of pannexin proteins, which display an architecture reminiscent of connexin hemichannels. In physiological conditions, gap junctions are usually open, while connexin hemichannels and, to a lesser extent, pannexin channels are typically closed, yet they can be activated by a number of pathological triggers. Several agents are available to inhibit channels built up by connexin and pannexin proteins, including alcoholic substances, glycyrrhetinic acid, anesthetics and fatty acids. These compounds not always strictly distinguish between gap junctions, connexin hemichannels and pannexin channels, and may have effects on other targets as well. An exception lies with mimetic peptides, which reproduce specific amino acid sequences in connexin or pannexin primary protein structure. In this paper, a state-of-the-art overview is provided on inhibitors of cellular channels consisting of connexins and pannexins with specific focus on their mode-of-action and therapeutic potential.
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Affiliation(s)
- Joost Willebrords
- Department of In Vitro Toxicology and Dermato-cosmetology, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Laarbeeklaan 103, Brussels, Belgium
| | - Michaël Maes
- Department of In Vitro Toxicology and Dermato-cosmetology, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Laarbeeklaan 103, Brussels, Belgium
| | - Sara Crespo Yanguas
- Department of In Vitro Toxicology and Dermato-cosmetology, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Laarbeeklaan 103, Brussels, Belgium
| | - Mathieu Vinken
- Department of In Vitro Toxicology and Dermato-cosmetology, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Laarbeeklaan 103, Brussels, Belgium.
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Zhao L, Li LI, Ma KT, Wang Y, Li J, Shi WY, Zhu HE, Zhang ZS, Si JQ. NSAIDs modulate GABA-activated currents via Ca 2+-activated Cl - channels in rat dorsal root ganglion neurons. Exp Ther Med 2016; 11:1755-1761. [PMID: 27168798 PMCID: PMC4840517 DOI: 10.3892/etm.2016.3158] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 02/11/2016] [Indexed: 12/11/2022] Open
Abstract
The ability of non-steroidal anti-inflammatory drugs (NSAIDs) to modulate γ-aminobutyrate (GABA)-activated currents via Ca2+-activated Cl− channels in rat dorsal root ganglion neurons (DRG), was examined in the present study. During the preparation of DRG neurons harvested from Sprague-Dawley rats, the whole-cell recording technique was used to record the effect of NSAIDs on GABA-activated inward currents, and the expression levels of the TMEM16A and TMEM16B subunits were revealed. In the event that DRG neurons were pre-incubated for 20 sec with niflumic acid (NFA) and 5-nitro-2-(3-phenylpropylamino) benzoic acid (NPPB) prior to the administration of GABA, the GABA-induced inward currents were diminished markedly in the majority of neurons examined (96.3%). The inward currents induced by 100 µmol/l GABA were attenuated by (0±0.09%; neurons = 4), (5.32±3.51%; neurons = 6), (21.3±4.00%; neurons = 5), (33.8±5.20%; neurons = 17), (52.2±5.10%; neurons = 4) and (61.1±4.12%; neurons = 12) by 0.1, 1, 3, 10, 30 and 100 µmol/l NFA, respectively. The inward currents induced by 100 µmol/l GABA were attenuated by (13.8±6%; neurons = 6), (23.2±14.7%; neurons = 6) and (29.7±9.1%; neurons = 9) by 3, 10 and 30 µmol/l NPPB, respectively. NFA and NPPB dose-dependently inhibited GABA-activated currents with half maximal inhibitory concentration (IC50) values of 6.7 and 11 µmol/l, respectively. The inhibitory effect of 100 µmol/l NFA on the GABA-evoked inward current were also strongly inhibited by nitrendipine (NTDP; an L-type calcium channel blocker), 1,2-bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid tetrakis (a highly selective calcium chelating reagent), caffeine (a widely available Ca2+ consuming drug) and calcium-free extracellular fluid, in a concentration-dependent manner. Immunofluorescent staining indicated that TMEM16A and TMEM16B expression was widely distributed in DRG neurons. The results suggest that NSAIDs may be able to regulate Ca2+-activated chloride channels to reduce GABAA receptor-mediated inward currents in DRGs.
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Affiliation(s)
- Lei Zhao
- Department of Physiology, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China; Electrophysiological Laboratory, Laboratory of Xinjiang Endemic and Ethnic Diseases, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China
| | - L I Li
- Department of Physiology, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China; Electrophysiological Laboratory, Laboratory of Xinjiang Endemic and Ethnic Diseases, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China
| | - Ke-Tao Ma
- Department of Physiology, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China; Electrophysiological Laboratory, Laboratory of Xinjiang Endemic and Ethnic Diseases, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China
| | - Yang Wang
- Department of Physiology, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China; Electrophysiological Laboratory, Laboratory of Xinjiang Endemic and Ethnic Diseases, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China; Department of Physiology, School of Basic Medical Sciences, Wuhan University, Wuhan, Hubei 430071, P.R. China
| | - Jing Li
- Department of Physiology, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China
| | - Wen-Yan Shi
- Department of Physiology, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China; Electrophysiological Laboratory, Laboratory of Xinjiang Endemic and Ethnic Diseases, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China
| | - H E Zhu
- Department of Physiology, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China; Electrophysiological Laboratory, Laboratory of Xinjiang Endemic and Ethnic Diseases, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China
| | - Zhong-Shuang Zhang
- Department of Physiology, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China; Electrophysiological Laboratory, Laboratory of Xinjiang Endemic and Ethnic Diseases, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China
| | - Jun-Qiang Si
- Department of Physiology, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China; Electrophysiological Laboratory, Laboratory of Xinjiang Endemic and Ethnic Diseases, Shihezi University Medical College, Shihezi, Xinjiang 832002, P.R. China; Department of Physiology, School of Basic Medical Sciences, Wuhan University, Wuhan, Hubei 430071, P.R. China; Department of Physiology, School of Basic Medical Sciences, Huazhong University of Science and Technology, Wuhan, Hubei 430030, P.R. China
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Bal R, Ustundag Y, Bulut F, Demir CF, Bal A. Flufenamic acid prevents behavioral manifestations of salicylate-induced tinnitus in the rat. Arch Med Sci 2016; 12:208-15. [PMID: 26925138 PMCID: PMC4754382 DOI: 10.5114/aoms.2016.57597] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Accepted: 05/21/2014] [Indexed: 11/17/2022] Open
Abstract
INTRODUCTION Tinnitus is defined as a phantom auditory sensation, the perception of sound in the absence of external acoustic stimulation. Given that flufenamic acid (FFA) blocks TRPM2 cation channels, resulting in reduced neuronal excitability, we aimed to investigate whether FFA suppresses the behavioral manifestation of sodium salicylate (SSA)-induced tinnitus in rats. MATERIAL AND METHODS Tinnitus was evaluated using a conditioned lick suppression model of behavioral testing. Thirty-one Wistar rats, randomly divided into four treatment groups, were trained and tested in the behavioral experiment: (1) control group: DMSO + saline (n = 6), (2) SSA group: DMSO + SSA (n = 6), (3) FFA group: FFA (66 mg/kg bw) + saline (n = 9), (4) FFA + SSA group: FFA (66 mg/kg bw) + SSA (400 mg/kg bw) (n = 10). Localization of TRPM2 to the plasma membrane of cochlear nucleus neurons was demonstrated by confocal microscopy. RESULTS Pavlovian training resulted in strong suppression of licking, having a mean value of 0.05 ±0.03 on extinction day 1, which is below the suppression training criterion level of 0.20 in control tinnitus animals. The suppression rate for rats having both FFA (66 mg/kg bw) and SSA (400 mg/kg bw) injections was significantly lower than that for the rats having SSA injections (p < 0.01). CONCLUSIONS We suggest that SSA-induced tinnitus could possibly be prevented by administration of a TRPM2 ion channel antagonist, FFA at 66 mg/kg bw.
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Affiliation(s)
- Ramazan Bal
- Department of Physiology, Faculty of Medicine, Gaziantep University, Gaziantep, Turkey
| | - Yasemin Ustundag
- Department of Anatomy, Faculty of Veterinary, Firat University, Elazig, Turkey
| | - Funda Bulut
- Department of Medical Biology, Faculty of Medicine, Kirikkale University, Kirikkale, Turkey
| | - Caner Feyzi Demir
- Department of Neurology, Faculty of Medicine, Firat University, Elazig, Turkey
| | - Ali Bal
- Department of Plastic-Reconstructive and Esthetic Surgery, Faculty of Medicine, Firat University, Elazig, Turkey
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15
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Alleviation of glutamate mediated neuronal insult by piroxicam in rodent model of focal cerebral ischemia: a possible mechanism of GABA agonism. J Physiol Biochem 2014; 70:901-13. [DOI: 10.1007/s13105-014-0358-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Accepted: 09/17/2014] [Indexed: 12/17/2022]
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16
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Akopian A, Atlasz T, Pan F, Wong S, Zhang Y, Völgyi B, Paul DL, Bloomfield SA. Gap junction-mediated death of retinal neurons is connexin and insult specific: a potential target for neuroprotection. J Neurosci 2014; 34:10582-91. [PMID: 25100592 PMCID: PMC4200109 DOI: 10.1523/jneurosci.1912-14.2014] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Revised: 06/06/2014] [Accepted: 06/27/2014] [Indexed: 01/02/2023] Open
Abstract
Secondary cell death via gap junctions (GJs) plays a role in the propagation of neuronal loss under a number of degenerative disorders. Here, we examined the role of GJs in neuronal death in the retina, which has arguably the most diverse expression of GJs in the CNS. Initially, we induced apoptotic death by injecting single retinal ganglion cells and glia with cytochrome C and found that this resulted in the loss of neighboring cells to which they were coupled via GJs. We next found that pharmacological blockade of GJs eradicated nearly all amacrine cell loss and reduced retinal ganglion cell loss by ∼70% after induction of either excitotoxic or ischemic insult conditions. These data indicate that the GJ-mediated secondary cell death was responsible for the death of most cells. Whereas genetic deletion of the GJ subunit Cx36 increased cell survivability by ∼50% under excitotoxic condition, cell loss in Cx45 knock-out mouse retinas was similar to that seen in wild-type mice. In contrast, ablation of Cx45 reduced neuronal loss by ∼50% under ischemic insult, but ablation of Cx36 offered no protection. Immunolabeling of the connexins showed differential changes in protein expression consistent with their differing roles in propagating death signals under the two insults. These data indicate that secondary cell death is mediated by different cohorts of GJs dependent on the connexins they express and the type of initial insult. Our results suggest that targeting specific connexins offers a novel therapeutic strategy to reduce progressive cell loss under different neurodegenerative conditions.
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Affiliation(s)
- Abram Akopian
- Department of Biological and Vision Sciences, State University of New York College of Optometry, New York, New York 10036, Department of Physiology & Neuroscience, New York University School of Medicine, New York, New York 10016
| | - Tamas Atlasz
- Department of Ophthalmology, New York University School of Medicine, New York, New York 10016, and
| | - Feng Pan
- Department of Biological and Vision Sciences, State University of New York College of Optometry, New York, New York 10036, Department of Physiology & Neuroscience, New York University School of Medicine, New York, New York 10016
| | - Sze Wong
- Department of Physiology & Neuroscience, New York University School of Medicine, New York, New York 10016
| | - Yi Zhang
- Department of Physiology & Neuroscience, New York University School of Medicine, New York, New York 10016
| | - Béla Völgyi
- Department of Ophthalmology, New York University School of Medicine, New York, New York 10016, and
| | - David L Paul
- Department of Neurobiology, Harvard Medical School, Boston, Massachusetts 02115
| | - Stewart A Bloomfield
- Department of Biological and Vision Sciences, State University of New York College of Optometry, New York, New York 10036, Department of Physiology & Neuroscience, New York University School of Medicine, New York, New York 10016, Department of Ophthalmology, New York University School of Medicine, New York, New York 10016, and
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17
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Uusi-Oukari M, Vähätalo L, Liljeblad A. Modifications of diflunisal and meclofenamate carboxyl groups affect their allosteric effects on GABAA receptor ligand binding. Neurochem Res 2014; 39:1183-91. [PMID: 24925262 DOI: 10.1007/s11064-014-1351-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Revised: 06/24/2013] [Accepted: 06/28/2013] [Indexed: 11/25/2022]
Abstract
Gamma-aminobutyric acid type A receptors (GABAAR) are allosterically modulated by the nonsteroidal anti-inflammatory drugs diflunisal and fenamates. The carboxyl group of these compounds is charged at physiological pH and therefore penetration of the compounds into the brain is low. In the present study we have transformed the carboxyl group of diflunisal and meclofenamate into non-ionizable functional groups and analyzed the effects of the modifications on stimulation of [(3)H]muscimol binding and on potentiation of γ-aminobutyric acid-induced displacement of 4'-ethenyl-4-n-[2,3-(3)H]propylbicycloorthobenzoate. N-Butylamide derivative of diflunisal modulated radioligand binding with equal or higher potency than the parent compound, while diflunisalamide showed reduced allosteric effect as compared to diflunisal. Amide derivative of meclofenamate equally affected radioligand binding parameters, while both diflunisal and meclofenamate methyl esters were less active than the parent compounds. Our study clearly demonstrates that an intact carboxyl group in diflunisal and meclofenamate is not indispensable for their positive GABAAR modulation. Further derivatization of the compound might yield compounds with higher selectivity for GABAARs that could be utilized in drug development.
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Affiliation(s)
- Mikko Uusi-Oukari
- Department of Pharmacology, Drug Development and Therapeutics, University of Turku, Itainen Pitkakatu 4, 20014, Turku, Finland,
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18
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Egawa K, Yamada J, Furukawa T, Yanagawa Y, Fukuda A. Cl⁻ homeodynamics in gap junction-coupled astrocytic networks on activation of GABAergic synapses. J Physiol 2013; 591:3901-17. [PMID: 23732644 PMCID: PMC3764636 DOI: 10.1113/jphysiol.2013.257162] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The electrophysiological properties and functional role of GABAergic signal transmission from neurons to the gap junction-coupled astrocytic network are still unclear. GABA-induced astrocytic Cl− flux has been hypothesized to affect the driving force for GABAergic transmission by modulating [Cl−]o. Thus, revealing the properties of GABA-mediated astrocytic responses will deepen our understanding of GABAergic signal transmission. Here, we analysed the Cl− dynamics of neurons and astrocytes in CA1 hippocampal GABAergic tripartite synapses, using Cl− imaging during GABA application, and whole cell recordings from interneuron–astrocyte pairs in the stratum lacunosum-moleculare. Astrocytic [Cl−]i was adjusted to physiological conditions (40 mm). Although GABA application evoked bidirectional Cl− flux via GABAA receptors and mouse GABA transporter 4 (mGAT4) in CA1 astrocytes, a train of interneuron firing induced only GABAA receptor-mediated inward currents in an adjacent astrocyte. A GAT1 inhibitor increased the interneuron firing-induced currents and induced bicuculline-insensitive, mGAT4 inhibitor-sensitive currents, suggesting that synaptic spillover of GABA predominantly induced the astrocytic Cl− efflux because GABAA receptors are localized near the synaptic clefts. This GABA-induced Cl− efflux was accompanied by Cl− siphoning via the gap junctions of the astrocytic network because gap junction inhibitors significantly reduced the interneuron firing-induced currents. Thus, Cl− efflux from astrocytes is homeostatically maintained within astrocytic networks. A gap junction inhibitor enhanced the activity-dependent depolarizing shifts of reversal potential of neuronal IPSCs evoked by repetitive stimulation to GABAergic synapses. These results suggest that Cl− conductance within the astrocytic network may contribute to maintaining GABAergic synaptic transmission by regulating [Cl−]o.
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Affiliation(s)
- Kiyoshi Egawa
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan
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19
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Baxendale S, Holdsworth CJ, Meza Santoscoy PL, Harrison MRM, Fox J, Parkin CA, Ingham PW, Cunliffe VT. Identification of compounds with anti-convulsant properties in a zebrafish model of epileptic seizures. Dis Model Mech 2012; 5:773-84. [PMID: 22730455 PMCID: PMC3484860 DOI: 10.1242/dmm.010090] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Accepted: 06/16/2012] [Indexed: 12/31/2022] Open
Abstract
The availability of animal models of epileptic seizures provides opportunities to identify novel anticonvulsants for the treatment of people with epilepsy. We found that exposure of 2-day-old zebrafish embryos to the convulsant agent pentylenetetrazole (PTZ) rapidly induces the expression of synaptic-activity-regulated genes in the CNS, and elicited vigorous episodes of calcium (Ca(2+)) flux in muscle cells as well as intense locomotor activity. We then screened a library of ∼2000 known bioactive small molecules and identified 46 compounds that suppressed PTZ-inducedtranscription of the synaptic-activity-regulated gene fos in 2-day-old (2 dpf) zebrafish embryos. Further analysis of a subset of these compounds, which included compounds with known and newly identified anticonvulsant properties, revealed that they exhibited concentration-dependent inhibition of both locomotor activity and PTZ-induced fos transcription, confirming their anticonvulsant characteristics. We conclude that this in situ hybridisation assay for fos transcription in the zebrafish embryonic CNS is a robust, high-throughput in vivo indicator of the neural response to convulsant treatment and lends itself well to chemical screening applications. Moreover, our results demonstrate that suppression of PTZ-induced fos expression provides a sensitive means of identifying compounds with anticonvulsant activities.
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Affiliation(s)
- Sarah Baxendale
- MRC Centre for Developmental and Biomedical Genetics, Department of Biomedical Science, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, UK
| | - Celia J. Holdsworth
- MRC Centre for Developmental and Biomedical Genetics, Department of Biomedical Science, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, UK
| | - Paola L. Meza Santoscoy
- MRC Centre for Developmental and Biomedical Genetics, Department of Biomedical Science, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, UK
| | - Michael R. M. Harrison
- MRC Centre for Developmental and Biomedical Genetics, Department of Biomedical Science, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, UK
| | - James Fox
- MRC Centre for Developmental and Biomedical Genetics, Department of Biomedical Science, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, UK
| | - Caroline A. Parkin
- MRC Centre for Developmental and Biomedical Genetics, Department of Biomedical Science, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, UK
| | - Philip W. Ingham
- MRC Centre for Developmental and Biomedical Genetics, Department of Biomedical Science, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, UK
| | - Vincent T. Cunliffe
- MRC Centre for Developmental and Biomedical Genetics, Department of Biomedical Science, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, UK
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20
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Armagan G, Turunc E, Kanit L, Yalcin A. Neuroprotection by mefenamic acid against D-serine: involvement of oxidative stress, inflammation and apoptosis. Free Radic Res 2012; 46:726-39. [PMID: 22369458 DOI: 10.3109/10715762.2012.669836] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Mefenamic acid, a non-steroidal antiinflammatory drug (NSAID), directly and dose-dependently exhibits neuroprotective activity. In our study, we investigated the effects of mefenamic acid against d-serine on oxidative stress in the hippocampus, cortex and cerebellum of rats. Furthermore, the potential inflammatory and apoptotic effects of d-serine and potential protective effect of mefenamic acid were determined at mRNA and protein levels of TNF-α, IL-1β, Bcl-2 and Bax. We found that d-serine significantly increased oxidative stress, levels of inflammation- and apoptosis-related molecules in a region specific manner. Mefenamic acid treatment provided significant protection against the elevation of lipid peroxidation, protein oxidation, levels of TNF-α, IL-1β and Bax. As a conclusion, we suggest that d-serine, as a potential neurodegenerative agent, may have a pivotal role in the regulation of oxidative stress, inflammation and apoptosis; and NSAIDs, such as mefenamic acid, may assist other therapeutics in treating disorders where d-serine-induced neurotoxic mechanisms are involved in.
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Affiliation(s)
- Guliz Armagan
- Department of Biochemistry, Faculty of Pharmacy, Ege University, Bornova, Izmir, Turkey
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21
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Rae MG, Hilton J, Sharkey J. Putative TRP channel antagonists, SKF 96365, flufenamic acid and 2-APB, are non-competitive antagonists at recombinant human α1β2γ2 GABA(A) receptors. Neurochem Int 2012; 60:543-54. [PMID: 22369768 DOI: 10.1016/j.neuint.2012.02.014] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2011] [Revised: 02/09/2012] [Accepted: 02/11/2012] [Indexed: 11/30/2022]
Abstract
Although transient receptor potential (TRP) channel biology research has expanded rapidly in recent years, the field is hampered by the widely held, but relatively poorly investigated, belief that most of the pharmacological tools used to investigate TRP channel function may not be particularly selective for their intended targets. The objective of this study was therefore to determine if this was indeed the case by systematically evaluating the effects of three routinely used putative TRP channel antagonists, SKF 96365, flufenamic acid (FF) and 2-aminoethoxydiphenyl borate (2-APB) against one of the most widely expressed CNS receptor subtypes CNS, the human α1β2γ2 GABA(A) receptor. Using whole cell patch-clamp recording to record responses to rapidly applied GABA in the absence and presence of the three putative antagonists in turn we found that SKF 96365 (1-100 μM) and FF (1-100 μM) significantly inhibited GABA responses of recombinant human α1β2γ2 GABA(A) receptor stably expressed in HEK293 cells with IC(50) values of 13.4 ± 5.1 and 1.9 ± 1.4 μM, respectively, suppressing the maximal response to GABA at all concentrations used in a manner consistent with a non-competitive mode of action. SKF 96365 and FF also both significantly reduced desensitisation and prolonged the deactivation kinetics of the receptors to GABA (1mM; P<0.05). 2-APB (10-1000 μM) also inhibited responses to GABA at all concentrations used with an IC(50) value of 16.7 ± 5.4 μM (n=3-5) but had no significant effect on the activation, desensitisation or deactivation kinetics of the GABA responses. Taken together this investigation revealed that these widely utilised TRP channel antagonists display significant 'off-target' effects at concentrations that are routinely used for the study of TRP channel function in numerous biological systems and as such, data which is obtained utilising these compounds should be interpreted with caution.
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Affiliation(s)
- M G Rae
- Department of Physiology, University College Cork, Ireland.
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22
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Khansari PS, Coyne L. NSAIDs in the treatment and/or prevention of neurological disorders. Inflammopharmacology 2012; 20:159-67. [DOI: 10.1007/s10787-011-0116-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2011] [Accepted: 12/21/2011] [Indexed: 12/26/2022]
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23
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Zifarelli G, Liantonio A, Gradogna A, Picollo A, Gramegna G, De Bellis M, Murgia AR, Babini E, Conte Camerino D, Pusch M. Identification of sites responsible for the potentiating effect of niflumic acid on ClC-Ka kidney chloride channels. Br J Pharmacol 2010; 160:1652-61. [PMID: 20649569 PMCID: PMC2936838 DOI: 10.1111/j.1476-5381.2010.00822.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2009] [Revised: 03/02/2010] [Accepted: 03/09/2010] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND AND PURPOSE ClC-K kidney Cl(-) channels are important for renal and inner ear transepithelial Cl(-) transport, and are potentially interesting pharmacological targets. They are modulated by niflumic acid (NFA), a non-steroidal anti-inflammatory drug, in a biphasic way: NFA activates ClC-Ka at low concentrations, but blocks the channel above approximately 1 mM. We attempted to identify the amino acids involved in the activation of ClC-Ka by NFA. EXPERIMENTAL APPROACH We used site-directed mutagenesis and two-electrode voltage clamp analysis of wild-type and mutant channels expressed in Xenopus oocytes. Guided by the crystal structure of a bacterial CLC homolog, we screened 97 ClC-Ka mutations for alterations of NFA effects. KEY RESULTS Mutations of five residues significantly reduced the potentiating effect of NFA. Two of these (G167A and F213A) drastically altered general gating properties and are unlikely to be involved in NFA binding. The three remaining mutants (L155A, G345S and A349E) severely impaired or abolished NFA potentiation. CONCLUSIONS AND IMPLICATIONS The three key residues identified (L155, G345, A349) are localized in two different protein regions that, based on the crystal structure of bacterial CLC homologs, are expected to be exposed to the extracellular side of the channel, relatively close to each other, and are thus good candidates for being part of the potentiating NFA binding site. Alternatively, the protein region identified mediates conformational changes following NFA binding. Our results are an important step towards the development of ClC-Ka activators for treating Bartter syndrome types III and IV with residual channel activity.
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Affiliation(s)
- G Zifarelli
- Istituto di Biofisica, Consiglio Nazionale delle RicercheGenova, Italy
| | - A Liantonio
- Istituto di Biofisica, Consiglio Nazionale delle RicercheGenova, Italy
- Sezione di Farmacologia, Dipartimento Farmacobiologico, Via Orabona 4, Università di BariBari, Italy
| | - A Gradogna
- Istituto di Biofisica, Consiglio Nazionale delle RicercheGenova, Italy
| | - A Picollo
- Istituto di Biofisica, Consiglio Nazionale delle RicercheGenova, Italy
| | - G Gramegna
- Istituto di Biofisica, Consiglio Nazionale delle RicercheGenova, Italy
- Sezione di Farmacologia, Dipartimento Farmacobiologico, Via Orabona 4, Università di BariBari, Italy
| | - M De Bellis
- Istituto di Biofisica, Consiglio Nazionale delle RicercheGenova, Italy
- Sezione di Farmacologia, Dipartimento Farmacobiologico, Via Orabona 4, Università di BariBari, Italy
| | - AR Murgia
- Istituto di Biofisica, Consiglio Nazionale delle RicercheGenova, Italy
| | - E Babini
- Istituto di Biofisica, Consiglio Nazionale delle RicercheGenova, Italy
| | - D Conte Camerino
- Sezione di Farmacologia, Dipartimento Farmacobiologico, Via Orabona 4, Università di BariBari, Italy
| | - M Pusch
- Istituto di Biofisica, Consiglio Nazionale delle RicercheGenova, Italy
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Thermodynamic and structural study of tolfenamic acid polymorphs. J Pharm Biomed Anal 2009; 50:831-40. [PMID: 19632801 DOI: 10.1016/j.jpba.2009.06.045] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2009] [Revised: 06/23/2009] [Accepted: 06/23/2009] [Indexed: 11/21/2022]
Abstract
The article deals with the study of two polymorphic modifications in the space groups P2(1)/c (white form) and P2(1)/n (yellow form) of the tolfenamic acid. It also describes how the white form vapor pressure temperature dependence was determined by using the transpiration method and how thermodynamic parameters of the sublimation process were calculated. We have estimated the difference between the crystal lattice energies of the two polymorphic forms by solution calorimetry and found that the crystal lattice energy of the yellow form is 6.7+/-1.2 kJ mol(-1) higher than that of the white form, whereas Gibbs free energies of the forms obtained from the vapor pressure temperature dependence are practically the same. The modifications under consideration are monotropically related. From the practical point of view, the white form is more preferable due to its lower crystal lattice energy and better performing procedure. We have also studied the solubility, solvation and transfer processes of the tolfenamic acid white form in buffers (with various values of pH and ionic strengths), n-hexane and n-octanol. The thermodynamic parameters of the investigated processes have been discussed and compared with those determined for others fenamates. In the study we estimated specific and non-specific contributions of the solvation enthalpic term of the fenamate molecules with the solvents as well. The driving forces of the transfer processes from the buffers with pH 7.4 and different ionic strengths to n-octanol were analyzed. It was found that the relationship between the enthalpic and entropic terms depends essentially on the ionic strength. For the considered fenamates the transfer processes of the neutral molecules and the ionic forms are enthalpy-determined, whereas for the niflumic acid this process is entropy-determined.
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Khansari PS, Halliwell RF. Evidence for neuroprotection by the fenamate NSAID, mefenamic acid. Neurochem Int 2009; 55:683-8. [PMID: 19563851 DOI: 10.1016/j.neuint.2009.06.014] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2008] [Revised: 06/18/2009] [Accepted: 06/18/2009] [Indexed: 11/27/2022]
Abstract
Fenamate NSAIDs are inhibitors of cyclooxygenases, antagonists of non-selective cation channels, subtype-selective modulators of GABA(A) receptors, weak inhibitors of glutamate receptors and activators of some potassium channels. These pharmacological actions are all implicated in the pathogenesis of ischemic stroke. The aim of this study was to investigate the hypothesis that the fenamate, mefenamic acid, is neuroprotective in an in vitro and in vivo model of stroke. Embryonic rat hippocampal neurons were cultured and maintained for up to 14 days in vitro. At 9 or 14 days, cells were exposed to glutamate (5microM) or glutamate (5microM) plus mefenamic acid (10-100microM) or the control agent, MK-801 (10microM) for 10min. 24h later, cell death was determined by measuring lactate dehydrogenase (LDH) levels in the culture media. In vivo, male Wistar rats (300-350g) were subjected to 2h middle cerebral artery occlusion (MCAO) followed by 24h reperfusion. Animals received either a single i.v. dose of MFA (10mg/kg or 30mg/kg), or MK-801 (2mg/kg) or saline prior to MCAO or, four equal doses of MFA (20mg/kg) at 1h intervals beginning 1h prior to MCAO. Ischemic damage was then assessed 24h after MCAO. In vitro, mefenamic acid (10-100microM) and MK-801 (10microM) significantly reduced glutamate-evoked cell death compared with control cultures. In vivo, MFA (20mg/kgx4) significantly reduced infarct volume, total ischemic brain damage and edema by 53% (p< or =0.02), 41% (p< or =0.002) and 45% (p< or =0.002) respectively. Furthermore, mefenamic acid reduced cerebral edema when measured as a function of brain water content. MK-801 was also neuroprotective against MCAO brain injury. This study demonstrates a significant neuroprotective effect by a fenamate NSAID against glutamate-induced cell toxicity, in vitro and against ischemic stroke in vivo. Further experiments are currently addressing the mechanism(s) of this neuroprotection.
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Juszczak GR, Swiergiel AH. Properties of gap junction blockers and their behavioural, cognitive and electrophysiological effects: animal and human studies. Prog Neuropsychopharmacol Biol Psychiatry 2009; 33:181-98. [PMID: 19162118 DOI: 10.1016/j.pnpbp.2008.12.014] [Citation(s) in RCA: 172] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2008] [Revised: 12/22/2008] [Accepted: 12/22/2008] [Indexed: 10/21/2022]
Abstract
Gap junctions play an important role in brain physiology. They synchronize neuronal activity and connect glial cells participating in the regulation of brain metabolism and homeostasis. Gap junction blockers (GJBs) include various chemicals that impair gap junction communication, disrupt oscillatory neuronal activity over a wide range of frequencies, and decrease epileptic discharges. The behavioural and clinical effects of GJBs suggest that gap junctions can be involved in the regulation of locomotor activity, arousal, memory, and breathing. Severe neuropsychiatric side effects suggest the involvement of gap junctions in mechanisms of consciousness. Unfortunately, the available GJBs are not selective and can bind to targets other than gap junctions. Other problems in behavioural studies include the possible adverse effects of GJBs, for example, retinal toxicity and hearing disturbances, changes in blood-brain transport, and the metabolism of other drugs. Therefore, it is necessary to design experiments properly to avoid false, misleading or uninterpretable results. We review the pharmacological properties and electrophysiological, behavioural and cognitive effects of the available gap junction blockers, such as carbenoxolone, glycyrrhetinic acid, quinine, quinidine, mefloquine, heptanol, octanol, anandamide, fenamates, 2-APB, several anaesthetics, retinoic acid, oleamide, spermine, aminosulfonates, and sodium propionate. It is concluded that despite a number of different problems, the currently used gap junction blockers could be useful tools in pharmacology and neuroscience.
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Affiliation(s)
- Grzegorz R Juszczak
- Department of Animal Behaviour, Institute of Genetics and Animal Breeding, Jastrzebiec, ul. Postepu 1, 05-552 Wolka Kosowska, Poland.
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Effects of fenamate on inhibitory postsynaptic currents in Purkinje’s cells. Bull Exp Biol Med 2008; 145:564-8. [DOI: 10.1007/s10517-008-0144-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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Differential pharmacological properties of GABAA/benzodiazepine receptor complex in dorsal compared to ventral rat hippocampus. Neurochem Int 2007; 52:1019-29. [PMID: 18069090 DOI: 10.1016/j.neuint.2007.10.016] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2007] [Revised: 10/15/2007] [Accepted: 10/26/2007] [Indexed: 11/21/2022]
Abstract
Several studies have indicated a functional differentiation across the septotemporal axis of rat hippocampus. Our previous results have shown that the alpha 1 beta 2 gamma 2-GABAA receptor subtype dominates in dorsal hippocampus (DH), while the alpha 2 beta 1 gamma 2-subtype prevails in ventral hippocampus (VH). We therefore studied possible differences in the pharmacological properties and receptor binding parameters of the GABAA receptor subtypes between DH and VH, by examining: (1)(a) the specific binding of [3H]-flunitrazepam (Benzodiazepine sites agonist) by using quantitative autoradiography, (b) the kinetic parameters of [3H]-flunitrazepam specific binding, by using the "wipe off" technique and (2) the competitive displacement of [3H]-flunitrazepam binding by using zolpidem (selective agonist of the alpha 1-subtype) and L-655,708 (selective inverse agonist of the alpha 5-subtype) and the enhancement of [3H]-flunitrazepam binding by using etomidate (selective positive modulator of the beta 2-subunit), in an autoradiographical saturation kinetic study. Our results showed in VH compared to DH: (A) lower level of [3H]-flunitrazepam binding, apparently due to weaker binding affinity (higher KD value), since no differences in the Bmax value could be detected, (B) higher IC50 values for zolpidem and lower IC50 values for L-655,708 and (C) higher EC50 values for etomidate. In conclusion, the lower binding for zolpidem and etomidate and the higher binding for L-655,708 observed in VH support the evidence that the alpha 1 beta 2 gamma 2-GABAA receptor subtype dominates in DH and the alpha 5-subtype prevails in VH. Further, our results suggest differential pharmacological effects of the benzodiazepines in DH compared to VH, with the sedative effects being more potent in the dorsal hippocampus.
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