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Kaplan A, Nash AI, Freeman AAH, Lewicki LG, Rye DB, Trotti LM, Brandt AL, Jenkins A. Commonly Used Therapeutics Associated with Changes in Arousal Inhibit GABA AR Activation. Biomolecules 2023; 13:biom13020365. [PMID: 36830736 PMCID: PMC9953295 DOI: 10.3390/biom13020365] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 02/07/2023] [Accepted: 02/09/2023] [Indexed: 02/17/2023] Open
Abstract
GABAA receptor-positive modulators are well-known to induce sedation, sleep, and general anesthesia. Conversely, GABAA receptor negative allosteric modulators (GABAARNAMs) can increase arousal and induce seizures. Motivated by our studies with patients with hypersomnia, and our discovery that two GABAARNAMs can restore the Excitation/Inhibition (E/I) balance in vitro and arousal in vivo, we chose to screen 11 compounds that have been reported to modulate arousal, to see if they shared a GABA-related mechanism. We determined modulation with both conventional and microfluidic patch clamp methods. We found that receptor activation was variably modulated by all 11 compounds: Rifampicin (RIF), Metronidazole (MET), Minocycline (MIN), Erythromycin (ERY), Ofloxacin (OFX), Chloroquine (CQ), Hydroxychloroquine sulfate (HCQ), Flumazenil (FLZ), Pentylenetetrazol (PTZ), (-)-Epigallocatechin Gallate (EGCG), and clarithromycin (CLR). The computational modeling of modulator-receptor interactions predicted drug action at canonical binding sites and novel orphan sites on the receptor. Our findings suggest that multiple avenues of investigation are now open to investigate large and brain-penetrant molecules for the treatment of patients with diminished CNS E/I balance.
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Affiliation(s)
- Anling Kaplan
- Department of Anesthesiology, Emory University, Atlanta, GA 30322, USA
| | - Abigail I. Nash
- Department of Medical Affairs, Janssen Scientific Affairs LLC, Titusville, NJ 08560, USA
| | | | - Lauren G. Lewicki
- School of Pharmacy, University of Saint Joseph, West Hartford, CT 06117, USA
| | - David B. Rye
- Department of Neurology, Emory University, Atlanta, GA 30322, USA
| | | | - Asher L. Brandt
- Department of Chemistry, University of Saint Joseph, West Hartford, CT 06117, USA
| | - Andrew Jenkins
- Department of Pharmaceutical Sciences, University of Saint Joseph, West Hartford, CT 06117, USA
- Correspondence:
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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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Xiao C, Han Y, Liu Y, Zhang J, Hu C. Relationship Between Fluoroquinolone Structure and Neurotoxicity Revealed by Zebrafish Neurobehavior. Chem Res Toxicol 2018; 31:238-250. [PMID: 29561132 DOI: 10.1021/acs.chemrestox.7b00300] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Central nervous system side effects are one of the most frequently reported adverse reactions of fluoroquinolones (FQs). However, the mechanism is not fully understood. In this study, zebrafish ( Danio rerio) were used as a model system. We quantified neurobehavior by recording indicators with automated video-tracking and used liquid chromatography-tandem mass spectrometry to detect drug absorption in vivo. We studied embryotoxicity and effects on zebrafish locomotor activity of 17 typical FQs. In addition, we calculated the stable conformation of typical FQs in aqueous conditions. The relationships between structure, neurotoxicity, and embryotoxicity were analyzed. The results indicate: (1) The effects of FQs on zebrafish neurobehavior can be divided into four categories. Type I has no significant influence on locomotor activity. Type II suppresses locomotor activity. Type III inhibits at low concentration and stimulates at high concentration. Type IV stimulates and then suppresses (biphasic response). (2) Structural modifications of FQs can change toxicity properties in zebrafish. Cleavage of the C-7 piperazinyl structure decreases neurotoxicity but enhances embryotoxicity. The C-3 decarboxyl formation and 5-NH2 derivatives might enhance embryotoxicity and neurotoxicity. (3) There are two toxic functional groups. The piperazinyl structure at position C-7 (toxic functional group I) can cause primary reactions which may be by the inhibition of γ-aminobutyric acid receptors, and the nucleus containing a carboxyl group at position 3 (toxic functional group II) might cause a reaction secondary to the effect of toxic functional group I and reverse its effects.
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Affiliation(s)
- Chaoqiang Xiao
- Chinese Academy of Medical Sciences and Peking Union Medical College , 100730 Beijing , China.,National Institutes for Food and Drug Control , 100050 Beijing , China
| | - Ying Han
- National Institutes for Food and Drug Control , 100050 Beijing , China
| | - Ying Liu
- National Institutes for Food and Drug Control , 100050 Beijing , China
| | - Jingpu Zhang
- Chinese Academy of Medical Sciences and Peking Union Medical College , 100730 Beijing , China
| | - Changqin Hu
- Chinese Academy of Medical Sciences and Peking Union Medical College , 100730 Beijing , China.,National Institutes for Food and Drug Control , 100050 Beijing , China
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Anticonvulsant effects of acetaminophen in mice: Comparison with the effects of nonsteroidal anti-inflammatory drugs. Epilepsy Res 2018; 140:22-28. [DOI: 10.1016/j.eplepsyres.2017.12.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Revised: 11/20/2017] [Accepted: 12/02/2017] [Indexed: 10/18/2022]
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Kamour A, Crichton S, Cooper G, Lupton DJ, Eddleston M, Vale JA, Thompson JP, Thomas SHL. Central nervous system toxicity of mefenamic acid overdose compared with other NSAIDs: an analysis of cases reported to the United Kingdom National Poisons Information Service. Br J Clin Pharmacol 2017; 83:855-862. [PMID: 27785820 PMCID: PMC5346865 DOI: 10.1111/bcp.13169] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 10/05/2016] [Accepted: 10/15/2016] [Indexed: 11/29/2022] Open
Abstract
AIMS Case reports and small case series suggest increased central nervous system (CNS) toxicity, especially convulsions, after overdose of mefenamic acid, compared with other nonsteroidal anti-inflammatory drugs (NSAIDs), although comparative epidemiological studies have not been conducted. The current study compared rates of CNS toxicity after overdose between mefenamic acid, ibuprofen, diclofenac and naproxen, as reported in telephone enquiries to the UK National Poisons Information Service (NPIS). METHODS NPIS telephone enquiries related to the four NSAIDs, received between January 2007 and December 2013, were analysed, comparing the frequency of reported CNS toxicity (convulsions, altered conscious level, agitation or aggression, confusion or disorientation) using multivariable logistic regression. RESULTS Of 22 937 patient-specific telephone enquiries, 10 398 did not involve co-ingestion of other substances (mefenamic acid 461, ibuprofen 8090, diclofenac 1300, naproxen 547). Patients taking mefenamic acid were younger and more commonly female than those using other NSAIDs. Those ingesting mefenamic acid were more likely to experience CNS toxicity than those ingesting the other NSAIDs combined [adjusted odds ratio (OR) 7.77, 95% confidence interval (CI) 5.68, 10.62], especially convulsions (adjusted OR 81.5, 95% CI 27.8, 238.8). Predictors of CNS toxicity included reported dose and age, but not gender. CONCLUSIONS Mefenamic acid overdose is associated with a much larger and dose-related risk of CNS toxicity, especially convulsions, compared with overdose of other NSAIDs. The benefit-risk profile of mefenamic acid should now be re-evaluated in light of effective and less toxic alternatives.
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Affiliation(s)
- Ashraf Kamour
- National Poisons Information Service, Newcastle UnitNewcastle upon Tyne Hospitals NHS Foundation TrustWolfson Unit, Claremont PlaceNewcastle upon TyneNE2 4HHUK
| | - Siobhan Crichton
- Department of Primary Care and Public HealthKing's College LondonCapital HouseLondonSE1 3QDUK
| | - Gill Cooper
- National Poisons Information Service, Cardiff UnitUniversity Hospital LlandoughPenlan Road, PenarthVale of GlamorganCF64 2XXUK
| | - David J. Lupton
- National Poisons Information Service, Edinburgh UnitRoyal Infirmary of Edinburgh51 Little France Crescent, Old Dalkeith RoadEdinburghEH16 4SAUK
| | - Michael Eddleston
- National Poisons Information Service, Edinburgh UnitRoyal Infirmary of Edinburgh51 Little France Crescent, Old Dalkeith RoadEdinburghEH16 4SAUK
- Pharmacology, Toxicology and Therapeutics, University/BHF Centre for Cardiovascular ScienceUniversity of Edinburgh47 Little France CrescentEdinburghEH16 4TJUK
| | - J. Allister Vale
- National Poisons Information Service, Birmingham UnitCity HospitalDudley RoadBirminghamB18 7QHUK
| | - John P. Thompson
- National Poisons Information Service, Cardiff UnitUniversity Hospital LlandoughPenlan Road, PenarthVale of GlamorganCF64 2XXUK
| | - Simon H. L. Thomas
- National Poisons Information Service, Newcastle UnitNewcastle upon Tyne Hospitals NHS Foundation TrustWolfson Unit, Claremont PlaceNewcastle upon TyneNE2 4HHUK
- Medical Toxicology Centre, Institute of Cellular Medicine, Wolfson BuildingNewcastle UniversityNewcastle upon TyneNE2 4HHUK
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Ahangar N, Esam Z, Bekhradnia A, Ebrahimzadeh MA. Hypothermic activity of acetaminophen; involvement of GABAA receptor, theoretical and experimental studies. IRANIAN JOURNAL OF BASIC MEDICAL SCIENCES 2016; 19:470-5. [PMID: 27403252 PMCID: PMC4923466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVES The mechanism of hypothermia action of acetaminophen (APAP) remains unclear even 125 years after its synthesis. Acetaminophen produces hypothermia. The mechanism of this reduction in core body temperature is not clear but evidence shows that it is not dependent on opioid and cannabinoid receptors. Because of strong documents about the roles of GABA and benzodiazepine receptors in hypothemic activity of some drugs such as diazepam, we determined if these receptors also contributes to the hypothermic effect of APAP. MATERIALS AND METHODS Diazepam (5 mg/kg, IP) was used for induction of hypothermia. Flumazenil (10 mg/kg, IP) or picrotoxin (2 mg/kg, IP) used for reversal of this effect. Rats injected with APAP (100, 200 or 300 mg/kg, IP). Baseline temperature measurements were taken with a digital thermometer via rectum. To evaluate the structural correlation between APAP and benzodiazepine receptor ligands, numerous models are selected and studied at HF/6-31G* level of theory. Relative energies, enthalpies and Gibbs free energies were calculated for all selected drugs. RESULTS Diazepam induced hypothermia was reversed by flumazenil or picrotoxin. Rats injected with APAP displayed dose- and time-related hypothermia. For combined administration, the hypothermic effect of APAP (200 mg/kg) was strongly reduced by pretreatment with picrotoxin or flumazenil P<0.0001and P<0.01, respectively. Selective structural data, bond length, dihedral angles, and related distance in pharmacophore of APAP and BZDR models were the same. Some significant structural analogues were obtained between these drugs. CONCLUSION Results suggest hypothermic action of acetaminophen may be mediate by its effect at GABAA benzodiazepine receptor.
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Affiliation(s)
- Nematollah Ahangar
- Pharmaceutical Sciences Research Center, School of Pharmacy, Mazandaran University of Medical Sciences, Sari, Iran
| | - Zohreh Esam
- Pharmaceutical Sciences Research Center, School of Pharmacy, Mazandaran University of Medical Sciences, Sari, Iran
| | - Ahmadreza Bekhradnia
- Pharmaceutical Sciences Research Center, School of Pharmacy, Mazandaran University of Medical Sciences, Sari, Iran
| | - Mohammad Ali Ebrahimzadeh
- Pharmaceutical Sciences Research Center, School of Pharmacy, Mazandaran University of Medical Sciences, Sari, Iran,Corresponding author: Mohammad Ali Ebrahimzadeh. Pharmaceutical Sciences Research Center, School of Pharmacy, Mazandaran University of Medical Sciences, Sari, Iran. Tel: +98-1133543081-3; Fax: +98-1133543084;
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7
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Pozo ED, Arana-Asensio E, García-López P. Acute Confusional Syndrome Induced by Moxifloxacin in an Elderly Man. J Am Geriatr Soc 2015; 63:2647-2648. [PMID: 26691713 DOI: 10.1111/jgs.13856] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Esperanza Del Pozo
- Department of Pharmacology, Faculty of Medicine, University of Granada, Granada, Spain.,Biomedical Research Institute ibs.Granada, Granada, Spain
| | | | - Pablo García-López
- Granada Health Center "Gran Capitán", Andalusia Health Service, Granada, Spain
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8
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Kaplan S, Eşrefoglu M, Aktaş A, Gül M, Önger ME, Altunkaynak ME, Ulkay MB, Ragbetli MÇ. The effect of prenatal exposure of a non-steroidal anti-inflammatory drug on the optic nerve of female rats: a stereological, histological, and electron microscopic study. J Matern Fetal Neonatal Med 2013; 26:1860-4. [DOI: 10.3109/14767058.2013.811227] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Gwanyanya A, Macianskiene R, Mubagwa K. Insights into the effects of diclofenac and other non-steroidal anti-inflammatory agents on ion channels. ACTA ACUST UNITED AC 2012; 64:1359-75. [PMID: 22943167 DOI: 10.1111/j.2042-7158.2012.01479.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVES Diclofenac and other non-steroidal anti-inflammatory drugs (NSAIDs) are widely used in the treatment of inflammation and pain. Most effects of NSAIDs are attributed to the inhibition of cyclooxygenases (COX). However, many NSAIDs may have other effects not related to COX, including the modulation of various ion channels. The clinical implications of the effects on channels are not fully understood. This review outlines the effects of NSAIDs, with special attention to diclofenac, on ion channels and highlights the possible underlying mechanisms. KEY FINDINGS NSAIDs have effects on channels such as inhibition, activation or changes in expression patterns. The channels affected include voltage-gated Na(+) , Ca(2+) , or K(+) channels, ligand-gated K(+) channels, transient receptor potential and other cation channels as well as chloride channels in several types of cells. The mechanisms of drug actions not related to COX inhibition may involve drug-channel interactions, interference with the generation of second messengers, changes in channel expression, or synergistic/antagonist interactions with other channel modulators. SUMMARY The effects on ion channels may account for novel therapeutic actions of NSAIDs or for adverse effects. Among the NSAIDs, diclofenac may serve as a template for developing new channel modulators and as a tool for investigating the actions of other drugs.
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Affiliation(s)
- Asfree Gwanyanya
- Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
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10
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Canan S, Aktaş A, Ulkay MB, Colakoglu S, Ragbetli MC, Ayyildiz M, Geuna S, Kaplan S. Prenatal exposure to a non‐steroidal anti‐inflammatory drug or saline solution impairs sciatic nerve morphology: a stereological and histological study. Int J Dev Neurosci 2008; 26:733-8. [DOI: 10.1016/j.ijdevneu.2008.07.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2008] [Revised: 06/27/2008] [Accepted: 07/06/2008] [Indexed: 11/24/2022] Open
Affiliation(s)
- Sinan Canan
- Department of PhysiologyBaskent University School of MedicineTR‐06530AnkaraTurkey
| | - Abit Aktaş
- Department of Histology and EmbryologyIstanbul University School of Veterinary MedicineTR‐34320IstanbulTurkey
| | - M. Basak Ulkay
- Department of Histology and EmbryologyIstanbul University School of Veterinary MedicineTR‐34320IstanbulTurkey
| | - Serdar Colakoglu
- Department of AnatomyDuzce University School of MedicineDuzceTurkey
| | - Murat Cetin Ragbetli
- Department of Histology and EmbryologyYüzüncü Yıl University School of MedicineVanTurkey
| | - Mustafa Ayyildiz
- Department of PhysiologyOndokuz Mayis University School of MedicineSamsunTurkey
| | - Stefano Geuna
- Dipartimento Di Scienze Cliniche E BiologicheUniversity Torino Ospedale San LuigiRegione Gonzole10‐10043OrbassanoTorinoItaly
| | - Suleyman Kaplan
- Department of Histology and EmbryologyOndokuz Mayis University School of MedicineTR‐55139SamsunTurkey
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11
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Liu LY, Fei XW, Li ZM, Zhang ZH, Mei YA. Diclofenac, a nonsteroidal anti-inflammatory drug, activates the transient outward K+ current in rat cerebellar granule cells. Neuropharmacology 2005; 48:918-26. [PMID: 15829261 DOI: 10.1016/j.neuropharm.2004.12.020] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2004] [Revised: 12/20/2004] [Accepted: 12/23/2004] [Indexed: 10/25/2022]
Abstract
Diclofenac, a nonsteroidal anti-inflammatory drug (NSAID), has been widely investigated in terms of its pharmacological action, but less is known about its direct effect on ion channels. Here, the effect of diclofenac on voltage-dependent transient outward K+ currents (I(A)) in cultured rat cerebellar granule cells was investigated using the whole-cell voltage-clamp technique. At concentrations of 10(-5)-10(-3) M, diclofenac reversibly increased the I(A) amplitude in a dose-dependent manner and significantly modulated the steady-state inactivation properties of the I(A) channels, but did not alter the steady-state activation properties. Furthermore, diclofenac treatment resulted in a slightly accelerated recovery from I(A) channel inactivation. Intracellular application of diclofenac could mimic the effects induced by extracellular application, although once the intracellular response reached a plateau, extracellular application of diclofenac could induce further increases in the current. These observations indicate that diclofenac might exert its effects on the channel protein at both the inner and outer sides of the cell membrane. Our data provide the first evidence that diclofenac is able to activate transient outward potassium channels in neurons. Although further work will be necessary to define the exact mechanism of diclofenac-induced I(A) channel activation, this study provides evidence that the nonsteroidal anti-inflammatory drug, diclofenac, may play a novel neuronal role that is worthy of future study.
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Affiliation(s)
- Lin-Yun Liu
- Center for Brain Science Research, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, Shanghai 200433, PR China
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12
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Dontas I, Sokolis DP, Giamarellos-Bourboulis EJ, Tzonou A, Giamarellou H, Karayannacos PE. The influence of indomethacin co-administration on ofloxacin levels in plasma and cerebrospinal fluid in rats. Int J Antimicrob Agents 2004; 23:371-6. [PMID: 15081086 DOI: 10.1016/j.ijantimicag.2003.09.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2003] [Accepted: 09/22/2003] [Indexed: 11/18/2022]
Abstract
The possible increase of ofloxacin levels in serum and cerebrospinal fluid (CSF) by concomitant indomethacin administration was investigated in 120 healthy adult rats. The animals were administered intramuscular doses of ofloxacin 30 mg/kg alone (Group A, n = 60) or with indomethacin 2 mg/kg (Group B, n = 60). Blood and CSF samples were obtained from both groups at 30, 45, 60 and 90 min post-administration. Concentrations of ofloxacin were estimated using a microbiological assay. Co-administration of indomethacin did not affect plasma levels of ofloxacin significantly; however, higher levels were found in all CSF samples after co-administration with indomethacin, particularly after 90 min with 0.59 microg/ml versus zero median values when only ofloxacin was administered (P = 0.05). No central nervous system adverse effects were observed clinically. No correlation between levels of ofloxacin in plasma and CSF could be established either in rats administered only ofloxacin or in rats administered both drugs. The presented pharmacokinetic findings revealed that co-administration of ofloxacin and indomethacin may result in protracted quinolone levels in the CSF. However, the absence of significant correlation between concentrations of ofloxacin in plasma and CSF upon co-administration of indomethacin, as well as of central nervous system adverse effects, make the probability of an epileptogenic interaction between them unlikely. These results merit further clinical evaluation.
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Affiliation(s)
- Ismene Dontas
- Laboratory of Experimental Surgery and Surgical Research, Medical School, University of Athens, Athens, Greece.
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Kudo C, Kori M, Matsuzaki K, Yamai K, Nakajima A, Shibuya A, Niwa H, Kamisaki Y, Wada K. Diclofenac inhibits proliferation and differentiation of neural stem cells. Biochem Pharmacol 2003; 66:289-95. [PMID: 12826271 DOI: 10.1016/s0006-2952(03)00235-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Nonsteroidal anti-inflammatory drugs (NSAIDs) are widely used in clinical situations as anti-inflammatory, analgesic and antipyretic drugs. However, it is still unknown whether NSAIDs have effects on the development of the central nervous system. In the present study, we investigated the effects of NSAIDs on neural stem cell (NSC) proliferation and differentiation into neurons. In contrast to aspirin, naproxen, indomethacin and ibuprofen, treatment with diclofenac (10 microM) for 2 days induced the death of NSCs in a concentration-dependent manner. Diclofenac also inhibited the proliferation of NSCs and their differentiation into neurons. Treatment with diclofenac resulted in nuclear condensation (a morphological change due to apoptosis of NSCs) 24hr after the treatment and activated caspase-3 after 6 hr, indicating that diclofenac may cause apoptosis of neuronal cells via activation of the caspase cascade. These results suggest that diclofenac may affect the development of the central nervous system.
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Affiliation(s)
- Chiho Kudo
- Department of Pharmacology, Graduate School of Dentistry, Osaka University, 1-8 Yamadaoka, Suita, Osaka 565-0871, Japan
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14
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Halliwell RF, Su J, Demuro A, Martinez-Torres A, Miledi R. Characterization of the interaction between a novel convulsant agent, norbiphen, and GABA(A) and other ligand-gated ion channels. Neuropharmacology 2002; 43:778-87. [PMID: 12367622 DOI: 10.1016/s0028-3908(02)00173-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
A hybrid molecule composed of the antimicrobial, norfloxacin, linked to the non-steroidal anti-inflammatory drug (NSAID), biphenylacetic acid, which we have termed norbiphen, is a lethal convulsant in vivo and an antagonist of rodent GABA(A) receptors in vitro. In the present study, the selectivity, molecular site(s) and mechanism of action of this novel convulsant were investigated using electrophysiological techniques. Sub-maximal GABA-evoked currents recorded from rodent hippocampal neurons were reversibly inhibited by norbiphen (1 microM) to 5+/-2% of control whereas glutamate, NMDA and glycine activated responses were little or unaffected. Sub-maximal GABA-evoked currents recorded from oocytes expressing recombinant human alpha1beta2gamma2s or alpha1beta2 GABA(A) receptors were also reversibly inhibited by norbiphen (1-1000 nM) with an IC(50) (+/-s.e.m.) of 5.7+/-1 and 8.8+/-1 nM, respectively. Similarly, GABA currents recorded from alpha1beta1gamma2s, alpha1beta1 and beta2gamma2s receptors were inhibited with IC(50)s of 16.1+/-1, 18.8+/-1 and 4.2+/-1 nM, respectively. In contrast, norbiphen (100 nM) had little or no effect at rho1 GABA(C) homomers. At alpha1beta2gamma2s receptors, norbiphen had no affect on the GABA reversal potential, and inhibition was not voltage-dependent, suggesting that this compound does not act at the ion channel. The GABA concentration response curve was shifted in a competitive-like fashion by norbiphen (10-300 nM) and a Schild analysis of these data yielded a slope of 0.94+/-0.1 and a pA(2) of 7.77. Our data reveal a novel, selective and highly potent antagonist of GABA(A) receptors. Norbiphen should be a valuable agent in future studies of this receptor complex.
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Affiliation(s)
- R F Halliwell
- School of Biological & Biomedical Sciences, University of Durham, UK.
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15
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Koutsoviti-Papadopoulou M, Nikolaidis E, Kounenis G. Biphenylacetic acid enhances the antagonistic action of fluoroquinolones on the GABA(A)-mediated responses of the isolated guinea-pig ileum. Pharmacol Res 2001; 44:229-33. [PMID: 11529690 DOI: 10.1006/phrs.2001.0853] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This paper examines the effect of biphenylacetic acid on the antagonistic action of norfloxacin and enoxacin on the GABA(A)-mediated responses of the isolated guinea-pig ileum. GABA produced transient contractions followed by relaxation. The contractile effect of exogenously applied GABA was concentration-dependent with EC(50)= 9.8 x 10(-6) M. This contractile effect was not significantly modified by biphenylacetic acid, and the EC(50) value for GABA in the presence of 10(-5) M biphenylacetic acid was 1.15 x 10(-5) M. The GABA contractile effect was inhibited, dose-dependently, by either norfloxacin or enoxacin, but only at concentrations higher than 10(-5) M. The response of the ileum to GABA (at EC(50)) was reduced to 35 and 36% by pretreatment with 10(-5) M norfloxacin or enoxacin, respectively. However, in the presence of 10(-5) M biphenylacetic acid, the response of the ileum to GABA was reduced to 2.2% by pretreatment with 10(-5) M enoxacin, while it was completely abolished by pretreatment with 10(-5) M norfloxacin and the IC(50) values were 5.5 x 10(-7) and 1.5 x 10(-6) M for norfloxacin and enoxacin, respectively. These data show that biphenylacetic acid whilst having no effect at the GABA(A)-mediated contractile response of the guinea-pig ileum, enhances the antagonistic effect of both enoxacin and norfloxacin. This suggests that combined administration of fluoroquinolones and biphenylacetic acid synergistically inhibits GABA(A)-receptors at the intestinal level.
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Affiliation(s)
- M Koutsoviti-Papadopoulou
- Department of Pharmacology, School of Veterinary Medicine, Aristotle University, Thessaloniki 540 06, Greece.
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Abstract
Convulsive episodes are associated with the use of a number of antimicrobial agents. Although seizures may be a feature of the disease being treated, antibiotics should be considered possible causes of seizures, particularly if suggested by temporal relationships between seizure activity and drug administration. The astute clinician should be aware of the clinical settings in which antibiotic-induced seizures occur, be familiar with likely agents and their mechanisms of toxicity, and be prepared to institute appropriate management directed at this adverse effect of antimicrobial therapy.
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Affiliation(s)
- K L Wallace
- Department of Medical Toxicology, Good Samaritan Regional Medical Center, Phoenix, Arizona, USA
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18
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Green MA, Halliwell RF. Selective antagonism of the GABA(A) receptor by ciprofloxacin and biphenylacetic acid. Br J Pharmacol 1997; 122:584-90. [PMID: 9351519 PMCID: PMC1564969 DOI: 10.1038/sj.bjp.0701411] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
1. Previous studies have shown that ciprofloxacin and biphenylacetic acid (BPAA) synergistically inhibit y-aminobutyric acid (GABA)A receptors. In the present study, we have investigated the actions of these two drugs on other neuronal ligand-gated ion channels. 2. Agonist-evoked depolarizations were recorded from rat vagus and optic nerves in vitro by use of an extracellular recording technique. 3. GABA (50 microM)-evoked responses, in the vagus nerve in vitro, were inhibited by bicuculline (0.3-10 microM) and picrotoxin (0.3-10 microM), with IC50 values and 95% confidence intervals (CI) of 1.2 microM (1.1-1.4) and 3.6 microM (3.0-4.3), respectively, and were potentiated by sodium pentobarbitone (30 microM) and diazepam (1 microM) to (mean+/-s.e.mean) 168+/-18% and 117+/-4% of control, respectively. 5-Hydroxytryptamine (5-HT; 0.5 microM)-evoked responses were inhibited by MDL 72222 (1 microM) to 10+/-4% of control; DMPP (10 microM)-evoked responses were inhibited by hexamethonium (100 microM) to 12+/-5% of control, and alphabetaMeATP (30 microM)-evoked responses were inhibited by PPADS (10 microM) to 21+/-5% of control. Together, these data are consistent with activation of GABA(A), 5-HT3, nicotinic ACh and P2X receptors, respectively. 4 Ciprofloxacin (10-3000 microM) inhibited GABA(A)-mediated responses in the vagus nerve with an IC50 (and 95% CI) of 202 microM (148-275). BPAA (1-1000 microM) had little or no effect on the GABA(A)-mediated response but concentration-dependently potentiated the effects of ciprofloxacin by up to 33,000 times. 5. Responses mediated by 5-HT3, nicotinic ACh and P2X receptors in the vagus nerve and strychnine-sensitive glycine receptors in the optic nerve were little or unaffected by ciprofloxacin (100 microM), BPAA (100 microM) or the combination of these drugs (both at 100 microM). 6. GABA (1 mM)-evoked responses in the optic nerve were inhibited by bicuculline with an IC50 of 3.6 microM (2.8-4.5), a value not significantly different from that determined in the vagus nerve. Ciprofloxacin also inhibited the GABA-evoked response with an IC50 of 334 microM (256-437) and BPAA (100 microM) potentiated these antagonist effects. However, the magnitude of the synergy was 48 times less than that seen in the vagus nerve. 7. These data indicate that ciprofloxacin and BPAA are selective antagonists of GABA(A) receptors, an action that may contribute to their excitatory effects in vivo. Additionally, our data suggest that the molecular properties of GABA(A) receptors in different regions of the CNS influence the extent to which these drugs synergistically inhibit the GABA(A) receptor.
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Affiliation(s)
- M A Green
- Department of Pharmacology, School of Health Sciences, University of Sunderland
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Vilchez JJ, Lago A, Burguera JA, Yaya R, Casanova V. Chlormethiazole in the management of the opsoclonus-myoclonus syndrome. J Int Med Res 1994; 22:55-62. [PMID: 8187945 DOI: 10.1177/030006059402200107] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Two instances of successful treatment of the rare ocular dyskinesia, opsoclonus, with chlormethiazole are reported. A 65-year-old woman had the opsoclonus-myoclonus syndrome associated with carcinoma of the breast; her myoclonia and opsoclonus did not respond to intravenous diazepam or phenytoin. Treatment with intravenous chlormethiazole resulted in rapid control of her myoclonic attacks, followed by slower but complete resolution of the opsoclonus. Following control of the acute symptoms the patient was transferred to an oral chlormethiazole maintenance dose which was further reduced and subsequently discontinued after 5 months, when the patient's overall clinical status had improved. A 53-year-old man with opsoclonia, myoclonia, ataxia and encephalopathy, not associated with neoplasia, was given immunosuppressor drugs to establish basal control, and oral chlormethiazole for symptomatic treatment. Almost immediately after the initial dose of chlormethiazole the patient became more orientated; he was sedated and the agitation and myoclonic fits were brought under control quite quickly. The opsoclonus responded progressively and was completely resolved after a few days. The initial oral dose of chlormethiazole was gradually reduced and was discontinued after 5-6 months. Chlormethiazole was well tolerated; it may have an important role in the management of the rare opsoclonus-myoclonus syndrome.
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Affiliation(s)
- J J Vilchez
- Department of Neurology, University Hospital La Fe, Valencia, Spain
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