Voltage-Dependent Inhibition of Glycine Receptor Channels by Niflumic Acid
Niflumic acid (NFA) is a member of the fenamate class of nonsteroidal anti-inflammatory drugs. This compound and its derivatives are used worldwide clinically for the relief of chronic and acute pain. NFA is also a commonly used blocker of voltage-gated chloride channels. Here we present evidence th...
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2017-05-01
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| Series: | Frontiers in Molecular Neuroscience |
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| Online Access: | http://journal.frontiersin.org/article/10.3389/fnmol.2017.00125/full |
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| author | Galyna Maleeva Galyna Maleeva Franck Peiretti Boris S. Zhorov Boris S. Zhorov Piotr Bregestovski Piotr Bregestovski |
| author_facet | Galyna Maleeva Galyna Maleeva Franck Peiretti Boris S. Zhorov Boris S. Zhorov Piotr Bregestovski Piotr Bregestovski |
| author_sort | Galyna Maleeva |
| collection | DOAJ |
| description | Niflumic acid (NFA) is a member of the fenamate class of nonsteroidal anti-inflammatory drugs. This compound and its derivatives are used worldwide clinically for the relief of chronic and acute pain. NFA is also a commonly used blocker of voltage-gated chloride channels. Here we present evidence that NFA is an efficient blocker of chloride-permeable glycine receptors (GlyRs) with subunit heterogeneity of action. Using the whole-cell configuration of patch-clamp recordings and molecular modeling, we analyzed the action of NFA on homomeric α1ΔIns, α2B, α3L, and heteromeric α1β and α2β GlyRs expressed in CHO cells. NFA inhibited glycine-induced currents in a voltage-dependent manner and its blocking potency in α2 and α3 GlyRs was higher than that in α1 GlyR. The Woodhull analysis suggests that NFA blocks α1 and α2 GlyRs at the fractional electrical distances of 0.16 and 0.65 from the external membrane surface, respectively. Thus, NFA binding site in α1 GlyR is closer to the external part of the membrane, while in α2 GlyR it is significantly deeper in the pore. Mutation G254A at the cytoplasmic part of the α1 GlyR pore-lining TM2 helix (level 2′) increased the NFA blocking potency, while incorporation of the β subunit did not have a significant effect. The Hill plot analysis suggests that α1 and α2 GlyRs are preferably blocked by two and one NFA molecules, respectively. Molecular modeling using Monte Carlo energy minimizations provides the structural rationale for the experimental data and proposes more than one interaction site along the pore where NFA can suppress the ion permeation. |
| first_indexed | 2024-12-10T21:48:22Z |
| format | Article |
| id | doaj.art-56220accee644122b4c246684b9b1c54 |
| institution | Directory Open Access Journal |
| issn | 1662-5099 |
| language | English |
| last_indexed | 2024-12-10T21:48:22Z |
| publishDate | 2017-05-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Molecular Neuroscience |
| spelling | doaj.art-56220accee644122b4c246684b9b1c542022-12-22T01:32:18ZengFrontiers Media S.A.Frontiers in Molecular Neuroscience1662-50992017-05-011010.3389/fnmol.2017.00125261576Voltage-Dependent Inhibition of Glycine Receptor Channels by Niflumic AcidGalyna Maleeva0Galyna Maleeva1Franck Peiretti2Boris S. Zhorov3Boris S. Zhorov4Piotr Bregestovski5Piotr Bregestovski6INSERM, INS, Institut de Neurosciences des Systèmes, Aix-Marseille UniversityMarseille, FranceDepartment of Cytology, Bogomoletz Institute of PhysiologyKyiv, UkraineINSERM 1062, INRA 1260, NORT, Aix-Marseille UniversityMarseille, FranceSechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of SciencesSt. Petersburg, RussiaDepartment of Biochemistry and Biomedical Sciences, McMaster UniversityHamilton, ON, CanadaINSERM, INS, Institut de Neurosciences des Systèmes, Aix-Marseille UniversityMarseille, FranceDepartment of Physiology, Kazan State Medical UniversityKazan, RussiaNiflumic acid (NFA) is a member of the fenamate class of nonsteroidal anti-inflammatory drugs. This compound and its derivatives are used worldwide clinically for the relief of chronic and acute pain. NFA is also a commonly used blocker of voltage-gated chloride channels. Here we present evidence that NFA is an efficient blocker of chloride-permeable glycine receptors (GlyRs) with subunit heterogeneity of action. Using the whole-cell configuration of patch-clamp recordings and molecular modeling, we analyzed the action of NFA on homomeric α1ΔIns, α2B, α3L, and heteromeric α1β and α2β GlyRs expressed in CHO cells. NFA inhibited glycine-induced currents in a voltage-dependent manner and its blocking potency in α2 and α3 GlyRs was higher than that in α1 GlyR. The Woodhull analysis suggests that NFA blocks α1 and α2 GlyRs at the fractional electrical distances of 0.16 and 0.65 from the external membrane surface, respectively. Thus, NFA binding site in α1 GlyR is closer to the external part of the membrane, while in α2 GlyR it is significantly deeper in the pore. Mutation G254A at the cytoplasmic part of the α1 GlyR pore-lining TM2 helix (level 2′) increased the NFA blocking potency, while incorporation of the β subunit did not have a significant effect. The Hill plot analysis suggests that α1 and α2 GlyRs are preferably blocked by two and one NFA molecules, respectively. Molecular modeling using Monte Carlo energy minimizations provides the structural rationale for the experimental data and proposes more than one interaction site along the pore where NFA can suppress the ion permeation.http://journal.frontiersin.org/article/10.3389/fnmol.2017.00125/fullchloride-permeable channelspatch-clamp recordingscys-loop receptorsWoodhull analysisMonte Carlo energy minimizations |
| spellingShingle | Galyna Maleeva Galyna Maleeva Franck Peiretti Boris S. Zhorov Boris S. Zhorov Piotr Bregestovski Piotr Bregestovski Voltage-Dependent Inhibition of Glycine Receptor Channels by Niflumic Acid Frontiers in Molecular Neuroscience chloride-permeable channels patch-clamp recordings cys-loop receptors Woodhull analysis Monte Carlo energy minimizations |
| title | Voltage-Dependent Inhibition of Glycine Receptor Channels by Niflumic Acid |
| title_full | Voltage-Dependent Inhibition of Glycine Receptor Channels by Niflumic Acid |
| title_fullStr | Voltage-Dependent Inhibition of Glycine Receptor Channels by Niflumic Acid |
| title_full_unstemmed | Voltage-Dependent Inhibition of Glycine Receptor Channels by Niflumic Acid |
| title_short | Voltage-Dependent Inhibition of Glycine Receptor Channels by Niflumic Acid |
| title_sort | voltage dependent inhibition of glycine receptor channels by niflumic acid |
| topic | chloride-permeable channels patch-clamp recordings cys-loop receptors Woodhull analysis Monte Carlo energy minimizations |
| url | http://journal.frontiersin.org/article/10.3389/fnmol.2017.00125/full |
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