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Yarotskyy V, Lark ARS, Nass SR, Hahn YK, Marone MG, McQuiston AR, Knapp PE, Hauser KF. Chloride channels with ClC-1-like properties differentially regulate the excitability of dopamine receptor D1- and D2-expressing striatal medium spiny neurons. Am J Physiol Cell Physiol 2022; 322:C395-C409. [PMID: 35080921 PMCID: PMC8917939 DOI: 10.1152/ajpcell.00397.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Dynamic chloride (Cl-) regulation is critical for synaptic inhibition. In mature neurons, Cl- influx and extrusion are primarily controlled by ligand-gated anion channels (GABAA and glycine receptors) and the potassium chloride cotransporter K+-Cl- cotransporter 2 (KCC2), respectively. Here, we report for the first time, to our knowledge, a presence of a new source of Cl- influx in striatal neurons with properties similar to chloride voltage-gated channel 1 (ClC-1). Using whole cell patch-clamp recordings, we detected an outwardly rectifying voltage-dependent current that was impermeable to the large anion methanesulfonate (MsO-). The anionic current was sensitive to the ClC-1 inhibitor 9-anthracenecarboxylic acid (9-AC) and the nonspecific blocker phloretin. The mean fractions of anionic current inhibition by MsO-, 9-AC, and phloretin were not significantly different, indicating that anionic current was caused by active ClC-1-like channels. In addition, we found that Cl- current was not sensitive to the transmembrane protein 16A (TMEM16A; Ano1) inhibitor Ani9 and that the outward Cl- rectification was preserved even at a very high intracellular Ca2+ concentration (2 mM), indicating that TMEM16B (Ano2) did not contribute to the total current. Western blotting and immunohistochemical analyses confirmed the presence of ClC-1 channels in the striatum mainly localized to the somata of striatal neurons. Finally, we found that 9-AC decreased action potential firing frequencies and increased excitability in medium spiny neurons (MSNs) expressing dopamine type 1 (D1) and type 2 (D2) receptors in the brain slices, respectively. We conclude that ClC-1-like channels are preferentially located at the somata of MSNs, are functional, and can modulate neuronal excitability.
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Affiliation(s)
- Viktor Yarotskyy
- 1Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia
| | - Arianna R. S. Lark
- 1Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia
| | - Sara R. Nass
- 1Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia
| | - Yun K. Hahn
- 2Department of Anatomy and Neurobiology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia
| | - Michael G. Marone
- 1Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia
| | - A. Rory McQuiston
- 2Department of Anatomy and Neurobiology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia
| | - Pamela E. Knapp
- 1Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia,2Department of Anatomy and Neurobiology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia,3Institute for Drug and Alcohol Studies, School of Medicine, Virginia Commonwealth University, Richmond, Virginia
| | - Kurt F. Hauser
- 1Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia,2Department of Anatomy and Neurobiology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia,3Institute for Drug and Alcohol Studies, School of Medicine, Virginia Commonwealth University, Richmond, Virginia
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Chizhov AV, Amakhin DV, Zaitsev AV. Mathematical model of Na-K-Cl homeostasis in ictal and interictal discharges. PLoS One 2019; 14:e0213904. [PMID: 30875397 PMCID: PMC6420042 DOI: 10.1371/journal.pone.0213904] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 03/04/2019] [Indexed: 12/22/2022] Open
Abstract
Despite big experimental data on the phenomena and mechanisms of the generation of ictal and interictal discharges (IDs and IIDs), mathematical models that can describe the synaptic interactions of neurons and the ionic dynamics in biophysical detail are not well-established. Based on experimental recordings of combined hippocampal-entorhinal cortex slices from rats in a high-potassium and a low-magnesium solution containing 4-aminopyridine as well as previous observations of similar experimental models, this type of mathematical model has been developed. The model describes neuronal excitation through the application of the conductance-based refractory density approach for three neuronal populations: two populations of glutamatergic neurons with hyperpolarizing and depolarizing GABAergic synapses and one GABAergic population. The ionic dynamics account for the contributions of voltage-gated and synaptic channels, active and passive transporters, and diffusion. The relatively slow dynamics of potassium, chloride, and sodium ion concentrations determine the transitions from pure GABAergic IIDs to IDs and GABA-glutamatergic IIDs. The model reproduces different types of IIDs, including those initiated by interneurons; repetitive IDs; tonic and bursting modes of an ID composed of clustered IID-like events. The simulations revealed contributions from different ionic channels to the ion concentration dynamics before and during ID generation. The proposed model is a step forward to an optimal mathematical description of the mechanisms of epileptic discharges.
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Affiliation(s)
- Anton V. Chizhov
- Computational Physics Laboratory, Ioffe Institute, Saint Petersburg, Russia
- Laboratory of Molecular Mechanisms of Neural Interactions, Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences, Saint Petersburg, Russia
- * E-mail:
| | - Dmitry V. Amakhin
- Laboratory of Molecular Mechanisms of Neural Interactions, Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences, Saint Petersburg, Russia
| | - Aleksey V. Zaitsev
- Laboratory of Molecular Mechanisms of Neural Interactions, Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences, Saint Petersburg, Russia
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Yelhekar TD, Druzin M, Johansson S. Contribution of Resting Conductance, GABA A-Receptor Mediated Miniature Synaptic Currents and Neurosteroid to Chloride Homeostasis in Central Neurons. eNeuro 2017; 4:ENEURO.0019-17.2017. [PMID: 28374007 PMCID: PMC5362935 DOI: 10.1523/eneuro.0019-17.2017] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2017] [Revised: 02/27/2017] [Accepted: 03/12/2017] [Indexed: 01/20/2023] Open
Abstract
Maintenance of a low intraneuronal Cl- concentration, [Cl-]i, is critical for inhibition in the CNS. Here, the contribution of passive, conductive Cl- flux to recovery of [Cl-]i after a high load was analyzed in mature central neurons from rat. A novel method for quantifying the resting Cl- conductance, important for [Cl-]i recovery, was developed and the possible contribution of GABAA and glycine receptors and of ClC-2 channels to this conductance was analyzed. The hypothesis that spontaneous, action potential-independent release of GABA is important for [Cl-]i recovery was tested. [Cl-]i was examined by gramicidin-perforated patch recordings in medial preoptic neurons. Cells were loaded with Cl- by combining GABA or glycine application with a depolarized voltage, and the time course of [Cl-]i was followed by measurements of the Cl- equilibrium potential, as obtained from the current recorded during voltage ramps combined with GABA or glycine application. The results show that passive Cl- flux contributes significantly, in the same order of magnitude as does K+-Cl- cotransporter 2 (KCC2), to [Cl-]i recovery and that Cl- conductance accounts for ∼ 6% of the total resting conductance. A major fraction of this resting Cl- conductance is picrotoxin (PTX)-sensitive and likely due to open GABAA receptors, but ClC-2 channels do not contribute. The results also show that when the decay of GABAA receptor-mediated miniature postsynaptic currents (minis) is slowed by the neurosteroid allopregnanolone, such minis may significantly quicken [Cl-]i recovery, suggesting a possible steroid-regulated role for minis in the control of Cl- homeostasis.
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Affiliation(s)
- Tushar D Yelhekar
- Department of Integrative Medical Biology, Umeå University , Umeå, SE-901 87, Sweden
| | - Michael Druzin
- Department of Integrative Medical Biology, Umeå University , Umeå, SE-901 87, Sweden
| | - Staffan Johansson
- Department of Integrative Medical Biology, Umeå University , Umeå, SE-901 87, Sweden
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