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Evlanenkov KK, Nikolaev MV, Potapieva NN, Bolshakov KV, Tikhonov DB. Probing the Proton-Gated ASIC Channels Using Tetraalkylammonium Ions. Biomolecules 2023; 13:1631. [PMID: 38002313 PMCID: PMC10669046 DOI: 10.3390/biom13111631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 11/04/2023] [Accepted: 11/05/2023] [Indexed: 11/26/2023] Open
Abstract
The action of tetraalkylammonium ions, from tetrametylammonium (TMA) to tetrapentylammonium (TPtA), on the recombinant and native acid-sensing ion channels (ASICs) was studied using the patch-clamp approach. The responses of ASIC1a, ASIC2a, and native heteromeric ASICs were inhibited by TPtA. The peak currents through ASIC3 were unaffected, whereas the steady-state currents were significantly potentiated. This effect was characterized by an EC50 value of 1.22 ± 0.12 mM and a maximal effect of 3.2 ± 0.5. The effects of TPtA were voltage-independent but significantly decreased under conditions of strong acidification, which caused saturation of ASIC responses. Molecular modeling predicted TPtA binding in the acidic pocket of closed ASICs. Bound TPtA can prevent acidic pocket collapse through a process involving ASIC activation and desensitization. Tetraethylammonium (TEA) inhibited ASIC1a and native ASICs. The effect was independent of the activating pH but decreased with depolarization, suggesting a pore-blocking mechanism.
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Affiliation(s)
| | | | | | | | - Denis B. Tikhonov
- Sechenov Institute of Evolutionary Physiology and Biochemistry RAS, St. Petersburg 194223, Russia or (K.K.E.); (M.V.N.); or (N.N.P.); or (K.V.B.)
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Mikhailova MM, Surin AM, Sobolevsky A, Yelshanskaya M, Bolshakov AP. Boris Izrailevich Khodorov: Scientist and Teacher. NEUROCHEM J+ 2022. [DOI: 10.1134/s1819712422040171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Phillips MB, Nigam A, Johnson JW. Interplay between Gating and Block of Ligand-Gated Ion Channels. Brain Sci 2020; 10:brainsci10120928. [PMID: 33271923 PMCID: PMC7760600 DOI: 10.3390/brainsci10120928] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 11/21/2020] [Accepted: 11/26/2020] [Indexed: 02/03/2023] Open
Abstract
Drugs that inhibit ion channel function by binding in the channel and preventing current flow, known as channel blockers, can be used as powerful tools for analysis of channel properties. Channel blockers are used to probe both the sophisticated structure and basic biophysical properties of ion channels. Gating, the mechanism that controls the opening and closing of ion channels, can be profoundly influenced by channel blocking drugs. Channel block and gating are reciprocally connected; gating controls access of channel blockers to their binding sites, and channel-blocking drugs can have profound and diverse effects on the rates of gating transitions and on the stability of channel open and closed states. This review synthesizes knowledge of the inherent intertwining of block and gating of excitatory ligand-gated ion channels, with a focus on the utility of channel blockers as analytic probes of ionotropic glutamate receptor channel function.
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Affiliation(s)
- Matthew B. Phillips
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA 15260, USA; (M.B.P.); (A.N.)
- Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Aparna Nigam
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA 15260, USA; (M.B.P.); (A.N.)
| | - Jon W. Johnson
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA 15260, USA; (M.B.P.); (A.N.)
- Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA 15260, USA
- Correspondence: ; Tel.: +1-(412)-624-4295
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Chen YS, Tu YC, Lai YC, Liu E, Yang YC, Kuo CC. Desensitization of NMDA channels requires ligand binding to both GluN1 and GluN2 subunits to constrict the pore beside the activation gate. J Neurochem 2019; 153:549-566. [PMID: 31821563 DOI: 10.1111/jnc.14939] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 12/04/2019] [Accepted: 12/04/2019] [Indexed: 11/27/2022]
Abstract
N-methyl-D-aspartate (NMDA) receptor channels are activated by glutamate (or NMDA) and glycine. The channels also undergo desensitization, which denotes decreased channel availability, after prolonged exposure to the activating ligands. Glycine apparently has a paradoxical negative effect on desensitization, as the increase in ambient glycine in concentrations required for channel activation would increase sustained NMDA receptor currents. We hypothesized that this classical "glycine-dependent desensitization" could be glycine-dependent activation in essence. By performing electrophysiological recordings and biophysical analyses with rat brain NMDA receptors heterogeneously expressed in Xenopus laevis oocytes, we characterized that the channel opened by "only" NMDA (in nominally glycine-free condition probably with the inevitable nanomolar glycine) would undergo a novel form of deactivation rather than desensitization, and is thus fully available for subsequent activation. Moreover, external tetrapentylammonium ions (TPentA), tetrabutylammonium ions, and tetrapropylammonium ions (TPA, in higher concentrations) block the pore and prohibit channel desensitization with a simple "foot-in-the-door" hindrance effect. TpentA and TPA have the same voltage dependence but show different flow dependence in binding affinity, revealing a common binding site at an electrical distance of ~0.7 from the outside yet differential involvement of the flux-coupling region in the external pore mouth. The smaller tetraethylammonium ion and the larger tetrahexylammonium and tetraheptylammonium ions may block the channel but could not affect desensitization. We conclude that NMDA receptor desensitization requires concomitant binding of both glycine and glutamate, and thus movement of both GluN1 and GluN2 subunits. Desensitization gate itself embodies a highly restricted pore reduction with a physical distance of ~4 Å from the charged nitrogen atom of bound tetraalkylammonium ions, and is located very close to the activation gate in the bundle-crossing region in the external pore vestibule.
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Affiliation(s)
- Yu-Shian Chen
- Department of Physiology, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Ya-Chi Tu
- Department of Physiology, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Yi-Chen Lai
- Department of Biomedical Sciences, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan
| | - Erin Liu
- Department of Physiology, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Ya-Chin Yang
- Department of Biomedical Sciences, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan.,Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan.,Neuroscience Research Center, Chang Gung Memorial Hospital, Linkou Medical Center, Tao-Yuan, Taiwan
| | - Chung-Chin Kuo
- Department of Physiology, National Taiwan University College of Medicine, Taipei, Taiwan.,Department of Neurology, National Taiwan University Hospital, Taipei, Taiwan
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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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Amygdaloid administration of tetrapentylammonium attenuates development of pain and anxiety-like behavior following peripheral nerve injury. Pharmacol Rep 2019; 71:54-60. [DOI: 10.1016/j.pharep.2018.08.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 06/28/2018] [Accepted: 08/16/2018] [Indexed: 02/07/2023]
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Rossokhin AV, Sharonova IN, Bukanova JV, Kolbaev SN, Skrebitsky VG. Block of GABA(A) receptor ion channel by penicillin: electrophysiological and modeling insights toward the mechanism. Mol Cell Neurosci 2014; 63:72-82. [PMID: 25305478 DOI: 10.1016/j.mcn.2014.10.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Revised: 09/29/2014] [Accepted: 10/07/2014] [Indexed: 11/26/2022] Open
Abstract
GABA(A) receptors (GABA(A)R) mainly mediate fast inhibitory neurotransmission in the central nervous system. Different classes of modulators target GABA(A)R properties. Penicillin G (PNG) belongs to the class of noncompetitive antagonists blocking the open GABA(A)R and is a prototype of β-lactam antibiotics. In this study, we combined electrophysiological and modeling approaches to investigate the peculiarities of PNG blockade of GABA-activated currents recorded from isolated rat Purkinje cells and to predict the PNG binding site. Whole-cell patch-сlamp recording and fast application system was used in the electrophysiological experiments. PNG block developed after channel activation and increased with membrane depolarization suggesting that the ligand binds within the open channel pore. PNG blocked stationary component of GABA-activated currents in a concentration-dependent manner with IC50 value of 1.12mM at -70mV. The termination of GABA and PNG co-application was followed by a transient tail current. Protection of the tail current from bicuculline block and dependence of its kinetic parameters on agonist affinity suggest that PNG acts as a sequential open channel blocker that prevents agonist dissociation while the channel remains blocked. We built the GABA(A)R models based on nAChR and GLIC structures and performed an unbiased systematic search of the PNG binding site. Monte-Carlo energy minimization was used to find the lowest energy binding modes. We have shown that PNG binds close to the intracellular vestibule. In both models the maximum contribution to the energy of ligand-receptor interactions revealed residues located on the level of 2', 6' and 9' rings formed by a bundle of M2 transmembrane segments, indicating that these residues most likely participate in PNG binding. The predicted structural models support the described mechanism of PNG block.
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Affiliation(s)
- Alexey V Rossokhin
- Research Center of Neurology, Russian Academy of Medical Sciences, 105064 Moscow, Russia.
| | - Irina N Sharonova
- Research Center of Neurology, Russian Academy of Medical Sciences, 105064 Moscow, Russia
| | - Julia V Bukanova
- Research Center of Neurology, Russian Academy of Medical Sciences, 105064 Moscow, Russia
| | - Sergey N Kolbaev
- Research Center of Neurology, Russian Academy of Medical Sciences, 105064 Moscow, Russia
| | - Vladimir G Skrebitsky
- Research Center of Neurology, Russian Academy of Medical Sciences, 105064 Moscow, Russia
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Kopanitsa MV, Yakubovska LM, Rudenko OP, Krishtal OA. Modulation of GABA(A) receptor-mediated currents by benzophenone derivatives in isolated rat Purkinje neurones. Neuropharmacology 2002; 43:764-77. [PMID: 12367621 DOI: 10.1016/s0028-3908(02)00120-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We investigated modulation of GABA(A) receptor-mediated whole-cell currents in cerebellar Purkinje neurones by several derivatives of benzophenone. A metabolite of phenazepam, 5-bromo-2'-chloro-2-aminobenzophenone (I), caused dual modification of peak amplitudes of GABA-gated currents that depended upon the concentration of applied GABA and incubation time. Following short 10 s pre-incubations, 1-30 microM I facilitated activation and delayed deactivation of currents evoked by 500 ms pulses of 20 microM GABA. In addition, 10 microM I prominently enhanced desensitisation of currents during applications of 500 microM GABA mainly by decreasing the value of the fast time constant of the desensitisation. Continuous 6 min incubation with 10 microM I during GABA stimulation or its administration between but not during 1 s pulses of 500 microM GABA led to a gradual, partly reversible attenuation of GABA-activated currents. This inhibition was not observed when I was applied only during pulses of GABA, indicating that the blockade was not use-dependent. One of the possible mechanisms of this down-modulation could be an intracellular effect of I, because when applied intracellularly it caused slow inhibition of responses to consecutive GABA pulses. When 3-30 microM I was applied on the background of small 'plateau'-like current 5-7 s after application of 500 microM GABA, it was able to block open channels with on and off rates similar to those observed with 30 microM picrotoxin but much slower than in the case of 500 microM benzylpenicillin. At a concentration of 10 microM, 5-substituted benzophenones, but not 2-aminobenzophenone or benzophenone itself, exhibited modulatory properties similar to I and distinct from those of picrotoxin and benzylpenicillin. Therefore, we conclude that derivatives of benzophenone are a novel class of GABA(A) receptor modulators with a unique pharmacological profile.
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Affiliation(s)
- M V Kopanitsa
- Department of Cellular Membranology, Bogomoletz Institute of Physiology, 4 Bogomoletz Street, Kyiv 01024, Ukraine.
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Sobolevsky AI, Yelshansky MV. The trapping block of NMDA receptor channels in acutely isolated rat hippocampal neurones. J Physiol 2000; 526 Pt 3:493-506. [PMID: 10922002 PMCID: PMC2270033 DOI: 10.1111/j.1469-7793.2000.t01-2-00493.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2000] [Accepted: 04/25/2000] [Indexed: 11/28/2022] Open
Abstract
N-methyl-D-aspartate (NMDA) receptor responses were recorded from acutely isolated rat hippocampal neurones using the whole-cell patch-clamp technique. A rapid perfusion system was used to study the voltage-dependent block of NMDA channels by Mg2+, amantadine (AM) and N-2-(adamantyl)-hexamethylenimine (A-7). Mg2+, AM and A-7-induced stationary blockade of NMDA channels increased with the blocker concentration but did not depend on the agonist (aspartate; Asp) concentration. Blockade by AM and A-7, but not Mg2+, was weakly use dependent. 'Hooked' tail currents were observed after coapplication of Asp and Mg2+, AM or A-7. The hooked tail current kinetics, amplitude and carried charge indicated that Mg2+, AM and A-7 did not prevent closure and desensitization of NMDA channels nor agonist dissociation. Tail currents following Asp application in the absence and continuous presence of Mg2+, AM or A-7 had similar kinetics. Application of multiple stationary and kinetic criteria to the Mg2+, AM and A-7 blockade led us to conclude that their effects on NMDA channels can be described in terms of a 'trapping' model, which is fully symmetrical with respect to the blocking transition. In general, the apparent blocking/recovery kinetics predicted by the fully symmetrical trapping model differ significantly from the microscopic kinetics and depend on the rate of binding and unbinding of the blocker, the NMDA channel open probability and the rate of solution exchange.
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Affiliation(s)
- A I Sobolevsky
- Institute of General Pathology 1s1sandand1 Pathophysiology, Baltiyskaya 8, 125315 Moscow, Russia.
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