1
|
Burman RJ, Diviney T, Călin A, Gothard G, Jouhanneau JSM, Poulet JFA, Sen A, Akerman CJ. Optogenetic Determination of Dynamic and Cell-Type-Specific Inhibitory Reversal Potentials. J Neurosci 2024; 44:e1392232024. [PMID: 38604778 PMCID: PMC11097265 DOI: 10.1523/jneurosci.1392-23.2024] [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: 07/24/2023] [Revised: 03/31/2024] [Accepted: 04/03/2024] [Indexed: 04/13/2024] Open
Abstract
The reversal potential refers to the membrane potential at which the net current flow through a channel reverses direction. The reversal potential is determined by transmembrane ion gradients and, in turn, determines how the channel's activity will affect the membrane potential. Traditional investigation into the reversal potential of inhibitory ligand-gated ion channels (EInh) has relied upon the activation of endogenous receptors, such as the GABA-A receptor (GABAAR). There are, however, challenges associated with activating endogenous receptors, including agonist delivery, isolating channel responses, and the effects of receptor saturation and desensitization. Here, we demonstrate the utility of using a light-gated anion channel, stGtACR2, to probe EInh in the rodent brain. Using mice of both sexes, we demonstrate that the properties of this optically activated channel make it a suitable proxy for studying GABAAR receptor-mediated inhibition. We validate this agonist-independent optogenetic strategy in vitro and in vivo and further show how it can accurately capture differences in EInh dynamics following manipulations of endogenous ion fluxes. This allows us to explore distinct resting EInh differences across genetically defined neuronal subpopulations. Using this approach to challenge ion homeostasis mechanisms in neurons, we uncover cell-specific EInh dynamics that are supported by the differential expression of endogenous ion handling mechanisms. Our findings therefore establish an effective optical strategy for revealing novel aspects of inhibitory reversal potentials and thereby expand the repertoire of optogenetics.
Collapse
Affiliation(s)
- Richard J Burman
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
- Oxford Epilepsy Research Group, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, United Kingdom
| | - Tara Diviney
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
| | - Alexandru Călin
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
| | - Gemma Gothard
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
| | - Jean-Sébastien M Jouhanneau
- Max-Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin 13125, Germany
- Neuroscience Research Center, Charité-Universitätsmedizin, Berlin 10117, Germany
| | - James F A Poulet
- Max-Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin 13125, Germany
- Neuroscience Research Center, Charité-Universitätsmedizin, Berlin 10117, Germany
| | - Arjune Sen
- Oxford Epilepsy Research Group, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, United Kingdom
| | - Colin J Akerman
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
| |
Collapse
|
2
|
Xue J, Brawner AT, Thompson JR, Yelhekar TD, Newmaster KT, Qiu Q, Cooper YA, Yu CR, Ahmed-Braima YH, Kim Y, Lin Y. Spatiotemporal Mapping and Molecular Basis of Whole-brain Circuit Maturation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.03.572456. [PMID: 38260331 PMCID: PMC10802351 DOI: 10.1101/2024.01.03.572456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Brain development is highly dynamic and asynchronous, marked by the sequential maturation of functional circuits across the brain. The timing and mechanisms driving circuit maturation remain elusive due to an inability to identify and map maturing neuronal populations. Here we create DevATLAS (Developmental Activation Timing-based Longitudinal Acquisition System) to overcome this obstacle. We develop whole-brain mapping methods to construct the first longitudinal, spatiotemporal map of circuit maturation in early postnatal mouse brains. Moreover, we uncover dramatic impairments within the deep cortical layers in a neurodevelopmental disorders (NDDs) model, demonstrating the utility of this resource to pinpoint when and where circuit maturation is disrupted. Using DevATLAS, we reveal that early experiences accelerate the development of hippocampus-dependent learning by increasing the synaptically mature granule cell population in the dentate gyrus. Finally, DevATLAS enables the discovery of molecular mechanisms driving activity-dependent circuit maturation.
Collapse
Affiliation(s)
- Jian Xue
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Andrew T Brawner
- Department of Psychiatry and Behavioral Sciences, SUNY Upstate Medical University, Syracuse, NY 13210, USA
- Neuroscience Graduate Program, SUNY Upstate Medical University, Syracuse, NY 13210, USA
- Equal contribution
| | - Jacqueline R Thompson
- Department of Psychiatry and Behavioral Sciences, SUNY Upstate Medical University, Syracuse, NY 13210, USA
- Neuroscience Graduate Program, SUNY Upstate Medical University, Syracuse, NY 13210, USA
- Equal contribution
| | - Tushar D Yelhekar
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Kyra T Newmaster
- Department of Neural and Behavioral Sciences, The Pennsylvania State University, Hershey, PA 17033, USA
| | - Qiang Qiu
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, MO 66160, USA
| | - Yonatan A Cooper
- Current address: Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
| | - C Ron Yu
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, MO 66160, USA
| | | | - Yongsoo Kim
- Department of Neural and Behavioral Sciences, The Pennsylvania State University, Hershey, PA 17033, USA
| | - Yingxi Lin
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
- Lead contact
| |
Collapse
|
3
|
Alharbi KS, Almalki WH, Alzarea SI, Kazmi I, Al-Abbasi FA, Afzal O, Altamimi ASA, Albratty M, Najmi A, Gupta G. Anaesthesia-induced Changes in Genomic Expression Leading to Neurodegeneration. CNS & NEUROLOGICAL DISORDERS DRUG TARGETS 2024; 23:411-419. [PMID: 37157197 DOI: 10.2174/1871527322666230508123558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 02/21/2023] [Accepted: 02/23/2023] [Indexed: 05/10/2023]
Abstract
General anaesthetics (GA) have been in continuous clinical use for more than 170 years, with millions of young and elderly populations exposed to GA to relieve perioperative discomfort and carry out invasive examinations. Preclinical studies have shown that neonatal rodents with acute and chronic exposure to GA suffer from memory and learning deficits, likely due to an imbalance between excitatory and inhibitory neurotransmitters, which has been linked to neurodevelopmental disorders. However, the mechanisms behind anaesthesia-induced alterations in late postnatal mice have yet to be established. In this narrative review, we present the current state of knowledge on early life anaesthesia exposure-mediated alterations of genetic expression, focusing on insights gathered on propofol, ketamine, and isoflurane, as well as the relationship between network effects and subsequent biochemical changes that lead to long-term neurocognitive abnormalities. Our review provides strong evidence and a clear picture of anaesthetic agents' pathological events and associated transcriptional changes, which will provide new insights for researchers to elucidate the core ideas and gain an in-depth understanding of molecular and genetic mechanisms. These findings are also helpful in generating more evidence for understanding the exacerbated neuropathology, impaired cognition, and LTP due to acute and chronic exposure to anaesthetics, which will be beneficial for the prevention and treatment of many diseases, such as Alzheimer's disease. Given the many procedures in medical practice that require continuous or multiple exposures to anaesthetics, our review will provide great insight into the possible adverse impact of these substances on the human brain and cognition.
Collapse
Affiliation(s)
- Khalid Saad Alharbi
- Department of Pharmacology, College of Pharmacy, Jouf University, Sakaka, Al-Jouf, Saudi Arabia
| | - Waleed Hassan Almalki
- Department of Pharmacology, College of Pharmacy, Umm Al-Qura University, Makkah, Saudi Arabia
| | - Sami I Alzarea
- Department of Pharmacology, College of Pharmacy, Jouf University, Sakaka, Al-Jouf, Saudi Arabia
| | - Imran Kazmi
- Department of Biochemistry, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Fahad A Al-Abbasi
- Department of Biochemistry, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Obaid Afzal
- Department of Pharmaceutical Chemistry, College of Pharmacy, Prince Sattam Bin Abdulaziz University, Al Kharj, 11942, Saudi Arabia
| | | | - Mohammed Albratty
- Department of Pharmaceutical Chemistry and Pharmacognosy, College of Pharmacy, Jazan University, P.O. Box. 114, Jazan 45142, Saudi Arabia
| | - Asim Najmi
- Department of Pharmaceutical Chemistry and Pharmacognosy, College of Pharmacy, Jazan University, P.O. Box. 114, Jazan 45142, Saudi Arabia
| | - Gaurav Gupta
- School of Pharmacy, Suresh Gyan Vihar University, Mahal Road, Jagatpura, 302017, Jaipur, India
- Department of Pharmacology, Saveetha Dental College, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai, India
| |
Collapse
|
4
|
Burman RJ, Brodersen PJN, Raimondo JV, Sen A, Akerman CJ. Active cortical networks promote shunting fast synaptic inhibition in vivo. Neuron 2023; 111:3531-3540.e6. [PMID: 37659408 DOI: 10.1016/j.neuron.2023.08.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 07/03/2023] [Accepted: 08/04/2023] [Indexed: 09/04/2023]
Abstract
Fast synaptic inhibition determines neuronal response properties in the mammalian brain and is mediated by chloride-permeable ionotropic GABA-A receptors (GABAARs). Despite their fundamental role, it is still not known how GABAARs signal in the intact brain. Here, we use in vivo gramicidin recordings to investigate synaptic GABAAR signaling in mouse cortical pyramidal neurons under conditions that preserve native transmembrane chloride gradients. In anesthetized cortex, synaptic GABAARs exert classic hyperpolarizing effects. In contrast, GABAAR-mediated synaptic signaling in awake cortex is found to be predominantly shunting. This is due to more depolarized GABAAR equilibrium potentials (EGABAAR), which are shown to result from the high levels of synaptic activity that characterize awake cortical networks. Synaptic EGABAAR observed in awake cortex facilitates the desynchronizing effects of inhibitory inputs upon local networks, which increases the flexibility of spiking responses to external inputs. Our findings therefore suggest that GABAAR signaling adapts to optimize cortical functions.
Collapse
Affiliation(s)
- Richard J Burman
- Department of Pharmacology, University of Oxford, Oxford, OX1 3QT, UK; Oxford Epilepsy Research Group, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, OX3 9DU, UK
| | | | - Joseph V Raimondo
- Division of Cell Biology, Department of Human Biology, Neuroscience Institute and Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Cape Town, 7935, South Africa
| | - Arjune Sen
- Oxford Epilepsy Research Group, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, OX3 9DU, UK
| | - Colin J Akerman
- Department of Pharmacology, University of Oxford, Oxford, OX1 3QT, UK.
| |
Collapse
|
5
|
Egawa K, Watanabe M, Shiraishi H, Sato D, Takahashi Y, Nishio S, Fukuda A. Imbalanced expression of cation-chloride cotransporters as a potential therapeutic target in an Angelman syndrome mouse model. Sci Rep 2023; 13:5685. [PMID: 37069177 PMCID: PMC10110603 DOI: 10.1038/s41598-023-32376-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 03/27/2023] [Indexed: 04/19/2023] Open
Abstract
Angelman syndrome is a neurodevelopmental disorder caused by loss of function of the maternally expressed UBE3A gene. Treatments for the main manifestations, including cognitive dysfunction or epilepsy, are still under development. Recently, the Cl- importer Na+-K+-Cl- cotransporter 1 (NKCC1) and the Cl- exporter K+-Cl- cotransporter 2 (KCC2) have garnered attention as therapeutic targets for many neurological disorders. Dysregulation of neuronal intracellular Cl- concentration ([Cl-]i) is generally regarded as one of the mechanisms underlying neuronal dysfunction caused by imbalanced expression of these cation-chloride cotransporters (CCCs). Here, we analyzed the regulation of [Cl-]i and the effects of bumetanide, an NKCC1 inhibitor, in Angelman syndrome models (Ube3am-/p+ mice). We observed increased NKCC1 expression and decreased KCC2 expression in the hippocampi of Ube3am-/p+ mice. The average [Cl-]i of CA1 pyramidal neurons was not significantly different but demonstrated greater variance in Ube3am-/p+ mice. Tonic GABAA receptor-mediated Cl- conductance was reduced, which may have contributed to maintaining the normal average [Cl-]i. Bumetanide administration restores cognitive dysfunction in Ube3am-/p+ mice. Seizure susceptibility was also reduced regardless of the genotype. These results suggest that an imbalanced expression of CCCs is involved in the pathophysiological mechanism of Ube3am-/p+ mice, although the average [Cl-]i is not altered. The blockage of NKCC1 may be a potential therapeutic strategy for patients with Angelman syndrome.
Collapse
Affiliation(s)
- Kiyoshi Egawa
- Department of Pediatrics, Hokkaido University Graduate School of Medicine, Kita 15, Nishi 7, Kita-Ku, Sapporo, 060-8638, Japan.
| | - Miho Watanabe
- Department of Neurophysiology, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-Ku, Hamamatsu City, Shizuoka, 431-3192, Japan
| | - Hideaki Shiraishi
- Department of Pediatrics, Hokkaido University Graduate School of Medicine, Kita 15, Nishi 7, Kita-Ku, Sapporo, 060-8638, Japan
| | - Daisuke Sato
- Department of Pediatrics, Hokkaido University Graduate School of Medicine, Kita 15, Nishi 7, Kita-Ku, Sapporo, 060-8638, Japan
| | - Yukitoshi Takahashi
- Department of Clinical Research, National Epilepsy Center, NHO, Shizuoka Institute of Epilepsy and Neurological Disorders, Urushiyama 886, Aoi-Ku, Shizuoka, 420-8688, Japan
| | - Saori Nishio
- Department of Rheumatology, Endocrinology, and Nephrology, Hokkaido University Graduate School of Medicine, Kita 15, Nishi 7, Kita-Ku, Sapporo, 060-8638, Japan
| | - Atsuo Fukuda
- Department of Neurophysiology, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-Ku, Hamamatsu City, Shizuoka, 431-3192, Japan
| |
Collapse
|
6
|
Das R, Ragagnin G, Sjöstedt J, Johansson M, Haage D, Druzin M, Johansson S, Bäckström T. Medroxyprogesterone acetate positively modulates specific GABA A-receptor subtypes - affecting memory and cognition. Psychoneuroendocrinology 2022; 141:105754. [PMID: 35395561 DOI: 10.1016/j.psyneuen.2022.105754] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 02/14/2022] [Accepted: 03/28/2022] [Indexed: 11/28/2022]
Abstract
Medroxyprogesterone acetate (MPA) is a progestin widely used in humans as hormone replacement therapy and at other indications. Many progestin metabolites, as the progesterone metabolite allopregnanolone, have GABAA-receptor modulatory effects and are known to affect memory, learning, appetite, and mood. In women, 4 years chronic treatment with MPA doubles the frequency of dementia and in rats, MPA causes cognitive impairment related to the GABAergic system. Activation of the membrane bound GABAA receptor results in a chloride ion flux that can be studied by whole-cell patch-clamp electrophysiological recordings. The purpose of this study was to clarify the modulatory effects of MPA and specific MPA metabolites, with structures like known GABAA-receptor modulators, on different GABAA-receptor subtypes. An additional aim was to verify the results as steroid effects on GABA response in single cells taken from rat hypothalamus. HEK-293 cell-lines permanently expressing the recombinant human GABAA-receptor subtype α1β2γ2L or α5β3γ2L or α2β3γ2S were created. The MPA metabolites 3α5α-MPA,3β5α-MPA and 3β5β-MPA were synthesised and purified for electrophysiological patch-clamp measurements with a Dynaflow system. The effects of MPA and tetrahydrodeoxycorticosterone were also studied. None of the studied MPA metabolites affected the responses mediated by α1β2γ2L or α5β3γ2L GABAA receptors. Contrary, MPA clearly acted both as a positive modulator and as a direct activator of the α5β3γ2L and α2β3γ2S GABAA receptors. However, in concentrations up to 10 μM, MPA was inactive at the α1β2γ2L GABAA receptor. In the patch-clamp recordings from dissociated cells of the preoptic area in rats, MPA increased the amplitude of responses to GABA. In addition, MPA alone without added GABA, evoked a current response. In conclusion, MPA acts as a positive modulator of specific GABAA receptor subtypes expressed in HEK cells and at native GABA receptors in single cells from the hypothalamic preoptic area.
Collapse
Affiliation(s)
- Roshni Das
- Department of Integrative medical biology, Umeå University, SE-901 87 Umeå, Sweden; Umecrine AB, Norrlands University Hospital Umeå, Building 6 M 4th floor, Sweden
| | - Gianna Ragagnin
- Umeå Neurosteroid Research Center, Department of Clinical sciences, Umeå University, SE-901 85 Umeå, Sweden
| | - Jessica Sjöstedt
- Umeå Neurosteroid Research Center, Department of Clinical sciences, Umeå University, SE-901 85 Umeå, Sweden
| | - Maja Johansson
- Umeå Neurosteroid Research Center, Department of Clinical sciences, Umeå University, SE-901 85 Umeå, Sweden; Umecrine AB, Norrlands University Hospital Umeå, Building 6 M 4th floor, Sweden
| | - David Haage
- Umeå Neurosteroid Research Center, Department of Clinical sciences, Umeå University, SE-901 85 Umeå, Sweden; Department of Nursing Sciences, Mid Sweden University, Sundsvall, Sweden; Umecrine AB, Norrlands University Hospital Umeå, Building 6 M 4th floor, Sweden
| | - Michael Druzin
- Department of Integrative medical biology, Umeå University, SE-901 87 Umeå, Sweden
| | - Staffan Johansson
- Department of Integrative medical biology, Umeå University, SE-901 87 Umeå, Sweden
| | - Torbjörn Bäckström
- Umeå Neurosteroid Research Center, Department of Clinical sciences, Umeå University, SE-901 85 Umeå, Sweden; Umecrine AB, Norrlands University Hospital Umeå, Building 6 M 4th floor, Sweden.
| |
Collapse
|
7
|
Chizhov AV, Amakhin DV, Smirnova EY, Zaitsev AV. Ictal wavefront propagation in slices and simulations with conductance-based refractory density model. PLoS Comput Biol 2022; 18:e1009782. [PMID: 35041661 PMCID: PMC8797236 DOI: 10.1371/journal.pcbi.1009782] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 01/28/2022] [Accepted: 12/21/2021] [Indexed: 12/04/2022] Open
Abstract
The mechanisms determining ictal discharge (ID) propagation are still not clear. In the present study, we aimed to examine these mechanisms in animal and mathematical models of epileptiform activity. Using double-patch and extracellular potassium ion concentration recordings in rat hippocampal-cortical slices, we observed that IDs moved at a speed of about 1 mm/s or less. The mechanisms of such slow propagation have been studied with a mathematical, conductance-based refractory density (CBRD) model that describes the GABA- and glutamatergic neuronal populations’ interactions and ion dynamics in brain tissue. The modeling study reveals two main factors triggerring IDs: (i) increased interneuronal activity leading to chloride ion accumulation and a consequent depolarizing GABAergic effect and (ii) the elevation of extracellular potassium ion concentration. The local synaptic transmission followed by local potassium ion extrusion and GABA receptor-mediated chloride ion accumulation underlies the ID wavefront’s propagation. In contrast, potassium ion diffusion in the extracellular space is slower and does not affect ID’s speed. The short discharges, constituting the ID, propagate much faster than the ID front. The accumulation of sodium ions inside neurons due to their hyperactivity and glutamatergic currents boosts the Na+/K+ pump, which terminates the ID. Knowledge of the mechanism of ID generation and propagation contributes to the development of new treatments against epilepsy. During an epileptic seizure, neuronal excitation spreads across the brain tissue and is accompanied by significant changes in ionic concentrations. Ictal discharge front spreads at low speeds, less than 1 mm/s. Mechanisms underlying this phenomenon are not yet well understood. We study these mechanisms using electrophysiological recordings in brain slices and computer simulations. Our detailed biophysical model describing neuronal populations’ interaction, spatial propagation, and ionic dynamics reproduces the generation and propagation of spontaneously repeating ictal discharges. The simulations are consistent with our recordings of the electrical activity and the extracellular potassium ion concentration. We distinguished between the two alternative mechanisms of the ictal wavefront propagation: (i) the diffusion of potassium ions released from excited neurons, which depolarizes distant neurons and thus supports excitation, and (ii) the axonal spread of excitation followed by the local extracellular potassium ion accumulation that supports the excitation. Our simulations provide evidence in favor of the latter mechanism. Our experiment-based modeling contributes to a mathematical description of brain tissue functioning and potentially contributes to developing new treatments against epilepsy.
Collapse
Affiliation(s)
- Anton V. Chizhov
- Laboratory of Molecular Mechanisms of Neural Interactions, Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences, Saint Petersburg, Russia
- Computational Physics Laboratory, Ioffe Institute, 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
| | - Elena Yu. Smirnova
- Laboratory of Molecular Mechanisms of Neural Interactions, Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences, Saint Petersburg, Russia
- Computational Physics Laboratory, Ioffe Institute, Saint Petersburg, Russia
- Institute of Experimental Medicine, Almazov National Medical Research Centre, 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
| |
Collapse
|
8
|
Bernardina NRD, de Lima RMS, Ronchi SN, Wan Der Mass EM, Souza GJ, Rodrigues LC, Bissoli NS, Brasil GA. Oxandrolone treatment in juvenile rats induced anxiety-like behavior in young adult animals. Neurosci Lett 2021; 761:136104. [PMID: 34256105 DOI: 10.1016/j.neulet.2021.136104] [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: 09/16/2020] [Revised: 06/29/2021] [Accepted: 07/05/2021] [Indexed: 10/20/2022]
Abstract
AIMS Oxandrolone (OXA) is a synthetic steroid used for the treatment of clinical conditions associated with catabolic states in humans, including children. However, its behavioral effects are not well known. Our goal was to evaluate the anxiety-like behavior induced in young adult rats after the treatment of juvenile animals with OXA. METHODS Four-week-old male rats were separated into three groups: Control (CON), therapeutic-like OXA dose (TD), and excessive OXA dose (ED), in which 2.5 and 37.5 mg/kg/day of OXA were administered via gavage for four weeks for TD and ED, respectively. Behavior was evaluated through the elevated plus maze (EPM) and open field (OF) tests. Protein expression of catalase (CAT), superoxide dismutase (SOD), Tumor necrosis factor-α (TNF-α), and dopamine receptor 2 (DrD2) were analyzed in tissue samples of the hippocampus, amygdala, and prefrontal cortex by Western Blot. RESULTS OXA induced anxiety-like behaviors in both TD and ED animals; it decreased the time spent in the open arms of the EPM in both groups and reduced the time spent in the central zone of the OF in the TD group. In the hippocampus, CAT expression was higher in TD compared with both control and ED animals. No differences were found in the amygdala and prefrontal cortex. TNF-α, SOD, and DrD2 levels were not altered in any of the assessed areas. CONCLUSIONS Treatment of juvenile rats with OXA led to anxiety-like behavior in young adult animals regardless of the dose used, with minor changes in the antioxidant machinery located in the hippocampus.
Collapse
Affiliation(s)
- Nara Rubia D Bernardina
- Department of Physiological Sciences, Federal University of Espírito Santo, Vitória, ES, Brazil
| | | | - Silas N Ronchi
- Department of Physiological Sciences, Federal University of Espírito Santo, Vitória, ES, Brazil
| | - Edgar M Wan Der Mass
- Department of Physiological Sciences, Federal University of Espírito Santo, Vitória, ES, Brazil
| | - Glauciene J Souza
- Department of Physiological Sciences, Federal University of Espírito Santo, Vitória, ES, Brazil
| | - Livia C Rodrigues
- Department of Physiological Sciences, Federal University of Espírito Santo, Vitória, ES, Brazil
| | - Nazaré S Bissoli
- Department of Physiological Sciences, Federal University of Espírito Santo, Vitória, ES, Brazil
| | - Girlandia A Brasil
- Pharmaceutical Sciences Graduate Program, University Vila Velha, Vila Velha, ES, Brazil.
| |
Collapse
|
9
|
Akita T, Fukuda A. Intracellular Cl - dysregulation causing and caused by pathogenic neuronal activity. Pflugers Arch 2020; 472:977-987. [PMID: 32300887 DOI: 10.1007/s00424-020-02375-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 03/23/2020] [Accepted: 03/27/2020] [Indexed: 02/06/2023]
Abstract
The intracellular Cl- concentration ([Cl-]i) is tightly regulated in brain neurons for stabilizing brain performance. The [Cl-]i in mature neurons is determined by the balance between the rate of Cl- extrusion mainly mediated by the neuron-specific type 2 K+-Cl- cotransporter (KCC2) and the rate of Cl- entry through various Cl- channels including GABAA receptors during neuronal activity. Disturbance of the balance causes instability of brain circuit performance and may lead to epileptic seizures. In the first part of this review, we discuss how genetic alterations in KCC2 in humans cause infantile migrating focal seizures, based on our previous report and others. Depolarization of the membrane potential increases the driving force for Cl- entry into neurons. Thus, the duration of action potential spike generation and the frequency of excitatory synaptic inputs are the crucial factors for determining the total amount of Cl- entry and the equilibrium [Cl-]i in neurons. Moreover, there is also a significant interdependence between the neuronal activity and the KCC2 expression. In the second part, we discuss plausible mechanisms by which excessive neuronal activity due to excitotoxic brain insults or other epilepsy-associated gene mutations may cause the Cl- imbalance in neurons and lead to epileptic discharges over the brain, using the schematic "unifying foci" model based on literature.
Collapse
Affiliation(s)
- Tenpei Akita
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu, 431-3192, Japan.
| | - Atsuo Fukuda
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu, 431-3192, Japan
| |
Collapse
|
10
|
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.
Collapse
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
| |
Collapse
|
11
|
Glykys J, Duquette E, Rahmati N, Duquette K, Staley KJ. Mannitol decreases neocortical epileptiform activity during early brain development via cotransport of chloride and water. Neurobiol Dis 2019; 125:163-175. [PMID: 30711483 DOI: 10.1016/j.nbd.2019.01.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 01/28/2019] [Accepted: 01/30/2019] [Indexed: 12/31/2022] Open
Abstract
Seizures and brain injury lead to water and Cl- accumulation in neurons. The increase in intraneuronal Cl- concentration ([Cl-]i) depolarizes the GABAA reversal potential (EGABA) and worsens seizure activity. Neocortical neuronal membranes have a low water permeability due to the lack of aquaporins necessary to move free water. Instead, neurons use cotransport of ions including Cl- to move water. Thus, increasing the extracellular osmolarity during seizures should result in an outward movement of water and salt, reducing [Cl-]i and improving GABAA receptor-mediated inhibition. We tested the effects of hyperosmotic therapy with a clinically relevant dose of mannitol (20 mM) on epileptiform activity, spontaneous multiunit activity, spontaneous inhibitory post-synaptic currents (sIPSCs), [Cl-]i, and neuronal volume in layer IV/V of the developing neocortex of C57BL/6 and Clomeleon mice. Using electrophysiological techniques and multiphoton imaging in acute brain slices (post-natal day 7-12) and organotypic neocortical slice cultures (post-natal day 14), we observed that mannitol: 1) decreased epileptiform activity, 2) decreased neuronal volume and [Cl-]i through CCCs, 3) decreased spontaneous multi-unit activity frequency but not amplitude, and 4) restored the anticonvulsant efficacy of the GABAA receptor modulator diazepam. Increasing extracellular osmolarity by 20 mOsm with hypertonic saline did not decrease epileptiform activity. We conclude that an increase in extracellular osmolarity by mannitol mediates the efflux of [Cl-]i and water through CCCs, which results in a decrease in epileptiform activity and enhances benzodiazepine actions in the developing neocortex in vitro. Novel treatments aimed to decrease neuronal volume may concomitantly decrease [Cl-]i and improve seizure control.
Collapse
Affiliation(s)
- J Glykys
- Department of Neurology, Massachusetts General Hospital, Boston 02114, United States; Harvard Medical School, Boston, MA 02115, United States.
| | - E Duquette
- Department of Neurology, Massachusetts General Hospital, Boston 02114, United States
| | - N Rahmati
- Department of Neurology, Massachusetts General Hospital, Boston 02114, United States; Harvard Medical School, Boston, MA 02115, United States
| | - K Duquette
- Department of Neurology, Massachusetts General Hospital, Boston 02114, United States; Northeastern University, Boston 02115, United States
| | - K J Staley
- Department of Neurology, Massachusetts General Hospital, Boston 02114, United States; Harvard Medical School, Boston, MA 02115, United States
| |
Collapse
|
12
|
Nesterov SV, Skorobogatova YA, Panteleeva AA, Pavlik LL, Mikheeva IB, Yaguzhinsky LS, Nartsissov YR. NMDA and GABA receptor presence in rat heart mitochondria. Chem Biol Interact 2018; 291:40-46. [PMID: 29883723 DOI: 10.1016/j.cbi.2018.06.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 05/30/2018] [Accepted: 06/05/2018] [Indexed: 11/19/2022]
Abstract
The purpose of this study is to demonstrate the presence of three more receptors in mitochondria. Two N-methyl-d-aspartate receptor (NMDAR) subunits (NR1 and NR2B) are found by protein immunoblot and immunogold labeling in mitochondria fraction isolated from rat heart. These data allow supposing NMDAR presence and functioning in the inner mitochondrial membrane. There are no signs of receptor presence obtained in heart tissue lysate, that indicates the receptor localization exactly in mitochondria. The possible receptor functions discussed are its participation in calcium transport and in excitation-metabolism coupling. Besides, preliminary evidence is obtained of GABAA and GABAB receptors presence in heart mitochondria. One can surmise their role in metabolism regulation and their possible co-operation with NMDAR just as in the nervous system.
Collapse
Affiliation(s)
- Semen V Nesterov
- Moscow Institute of Physics and Technology, Institutskiy pereulok, 9, Dolgoprudny, 141700, Russia.
| | - Yulia A Skorobogatova
- Moscow Institute of Physics and Technology, Institutskiy pereulok, 9, Dolgoprudny, 141700, Russia.
| | - Alisa A Panteleeva
- Belozersky Research Institute for Physico Chemical Biology, Lomonosov Moscow State University, Moscow, 119992, Russia.
| | - Lyubov L Pavlik
- Institute of Theoretical and Experimental Biophisics Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia.
| | - Irina B Mikheeva
- Institute of Theoretical and Experimental Biophisics Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia.
| | - Lev S Yaguzhinsky
- Institute of Cytochemistry and Molecular Pharmacology, 6-th Radialnaya str. 24-14, Moscow, 115404, Russia; Belozersky Research Institute for Physico Chemical Biology, Lomonosov Moscow State University, Moscow, Russia.
| | - Yaroslav R Nartsissov
- Institute of Cytochemistry and Molecular Pharmacology, 6-th Radialnaya str. 24-14, Moscow, 115404, Russia.
| |
Collapse
|
13
|
Computational model of interictal discharges triggered by interneurons. PLoS One 2017; 12:e0185752. [PMID: 28977038 PMCID: PMC5627938 DOI: 10.1371/journal.pone.0185752] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Accepted: 09/19/2017] [Indexed: 11/19/2022] Open
Abstract
Interictal discharges (IIDs) are abnormal waveforms registered in the periods before or between seizures. IIDs that are initiated by GABAergic interneurons have not been mathematically modeled yet. In the present study, a mathematical model that describes the mechanisms of these discharges is proposed. The model is based on the experimental recordings of IIDs in pyramidal neurons of the rat entorhinal cortex and estimations of synaptic conductances during IIDs. IIDs were induced in cortico-hippocampal slices by applying an extracellular solution with 4-aminopyridine, high potassium, and low magnesium concentrations. Two different types of IIDs initiated by interneurons were observed. The first type of IID (IID1) was pure GABAergic. The second type of IID (IID2) was induced by GABAergic excitation and maintained by recurrent interactions of both GABA- and glutamatergic neuronal populations. The model employed the conductance-based refractory density (CBRD) approach, which accurately approximates the firing rate of a population of similar Hodgkin-Huxley-like neurons. The model of coupled excitatory and inhibitory populations includes AMPA, NMDA, and GABA-receptor-mediated synapses and gap junctions. These neurons receive both arbitrary deterministic input and individual colored Gaussian noise. Both types of IIDs were successfully reproduced in the model by setting two different depolarized levels for GABA-mediated current reversal potential. It was revealed that short-term synaptic depression is a crucial factor in ceasing each of the discharges, and it also determines their durations and frequencies.
Collapse
|