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Gimenez-Gomez P, Le T, Martin GE. Modulation of neuronal excitability by binge alcohol drinking. Front Mol Neurosci 2023; 16:1098211. [PMID: 36866357 PMCID: PMC9971943 DOI: 10.3389/fnmol.2023.1098211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Accepted: 01/19/2023] [Indexed: 02/16/2023] Open
Abstract
Drug use poses a serious threat to health systems throughout the world. The number of consumers rises every year being alcohol the drug of abuse most consumed causing 3 million deaths (5.3% of all deaths) worldwide and 132.6 million disability-adjusted life years. In this review, we present an up-to-date summary about what is known regarding the global impact of binge alcohol drinking on brains and how it affects the development of cognitive functions, as well as the various preclinical models used to probe its effects on the neurobiology of the brain. This will be followed by a detailed report on the state of our current knowledge of the molecular and cellular mechanisms underlying the effects of binge drinking on neuronal excitability and synaptic plasticity, with an emphasis on brain regions of the meso-cortico limbic neurocircuitry.
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Affiliation(s)
- Pablo Gimenez-Gomez
- Department of Neurobiology, University of Massachusetts Chan Medical School, Worcester, MA, United States
- The Brudnick Neuropsychiatric Research Institute, Worcester, MA, United States
| | - Timmy Le
- Department of Neurobiology, University of Massachusetts Chan Medical School, Worcester, MA, United States
- The Brudnick Neuropsychiatric Research Institute, Worcester, MA, United States
- Graduate Program in Neuroscience, Morningside Graduate School of Biomedical Sciences, UMass Chan Medical School, Worcester, MA, United States
| | - Gilles E. Martin
- Department of Neurobiology, University of Massachusetts Chan Medical School, Worcester, MA, United States
- The Brudnick Neuropsychiatric Research Institute, Worcester, MA, United States
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McCoy MT, Jayanthi S, Cadet JL. Potassium Channels and Their Potential Roles in Substance Use Disorders. Int J Mol Sci 2021; 22:1249. [PMID: 33513859 PMCID: PMC7865894 DOI: 10.3390/ijms22031249] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 01/19/2021] [Accepted: 01/22/2021] [Indexed: 01/12/2023] Open
Abstract
Substance use disorders (SUDs) are ubiquitous throughout the world. However, much remains to be done to develop pharmacotherapies that are very efficacious because the focus has been mostly on using dopaminergic agents or opioid agonists. Herein we discuss the potential of using potassium channel activators in SUD treatment because evidence has accumulated to support a role of these channels in the effects of rewarding drugs. Potassium channels regulate neuronal action potential via effects on threshold, burst firing, and firing frequency. They are located in brain regions identified as important for the behavioral responses to rewarding drugs. In addition, their expression profiles are influenced by administration of rewarding substances. Genetic studies have also implicated variants in genes that encode potassium channels. Importantly, administration of potassium agonists have been shown to reduce alcohol intake and to augment the behavioral effects of opioid drugs. Potassium channel expression is also increased in animals with reduced intake of methamphetamine. Together, these results support the idea of further investing in studies that focus on elucidating the role of potassium channels as targets for therapeutic interventions against SUDs.
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Affiliation(s)
| | | | - Jean Lud Cadet
- Molecular Neuropsychiatry Research Branch, NIDA Intramural Research Program, Baltimore, MD 21224, USA; (M.T.M.); (S.J.)
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Farhoodi R, Lansdell BJ, Kording KP. Quantifying How Staining Methods Bias Measurements of Neuron Morphologies. Front Neuroinform 2019; 13:36. [PMID: 31191283 PMCID: PMC6541099 DOI: 10.3389/fninf.2019.00036] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Accepted: 04/25/2019] [Indexed: 12/20/2022] Open
Abstract
The process through which neurons are labeled is a key methodological choice in measuring neuron morphology. However, little is known about how this choice may bias measurements. To quantify this bias we compare the extracted morphology of neurons collected from the same rodent species, experimental condition, gender distribution, age distribution, brain region and putative cell type, but obtained with 19 distinct staining methods. We found strong biases on measured features of morphology. These were largest in features related to the coverage of the dendritic tree (e.g., the total dendritic tree length). Understanding measurement biases is crucial for interpreting morphological data.
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Affiliation(s)
- Roozbeh Farhoodi
- Department of Mathematics, Sharif University of Technology, Tehran, Iran
| | | | - Konrad Paul Kording
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, United States.,Department of Neuroscience, University of Pennsylvania, Philadelphia, PA, United States
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Bray JG, Reyes KC, Roberts AJ, Gruol DL. Altered hippocampal synaptic function in transgenic mice with increased astrocyte expression of CCL2 after withdrawal from chronic alcohol. Neuropharmacology 2018; 135:113-125. [PMID: 29499275 DOI: 10.1016/j.neuropharm.2018.02.031] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Revised: 02/22/2018] [Accepted: 02/26/2018] [Indexed: 11/29/2022]
Abstract
CNS actions of the chemokine CCL2 are thought to play a role in a variety of conditions that can have detrimental consequences to CNS function, including alcohol use disorders. We used transgenic mice that express elevated levels of CCL2 in the CNS (CCL2-tg) and their non-transgenic (non-tg) littermate control mice to investigate long-term consequences of CCL2/alcohol/withdrawal interactions on hippocampal synaptic function, including excitatory synaptic transmission, somatic excitability, and synaptic plasticity. Two alcohol exposure paradigms were tested, a two-bottle choice alcohol (ethanol) drinking protocol (2BC drinking) and a chronic intermittent alcohol (ethanol) (CIE/2BC) protocol. Electrophysiological measurements of hippocampal function were made ex vivo, starting ∼0.6 months after termination of alcohol exposure. Both alcohol exposure/withdrawal paradigms resulted in CCL2-dependent interactions that altered the effects of alcohol on synaptic function. The synaptic alterations differed for the two alcohol exposure paradigms. The 2BC drinking/withdrawal treatment had no apparent long-term consequences on synaptic responses and long-term potentiation (LTP) in hippocampal slices from non-tg mice, whereas synaptic transmission was reduced but LTP was enhanced in hippocampal slices from CCL2-tg mice. In contrast, the CIE/2BC/withdrawal treatment enhanced synaptic transmission but reduced LTP in the non-tg hippocampus, whereas there were no apparent long-term consequences to synaptic transmission and LTP in hippocampus from CCL2-tg mice, although somatic excitability was enhanced. These results support the idea that alcohol-induced CCL2 production can modulate the effects of alcohol exposure/withdrawal on synaptic function and indicate that CCL2/alcohol interactions can vary depending on the alcohol exposure/withdrawal protocol used.
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Affiliation(s)
- Jennifer G Bray
- Molecular and Cellular Neuroscience Department, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Kenneth C Reyes
- Molecular and Cellular Neuroscience Department, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Amanda J Roberts
- Molecular and Cellular Neuroscience Department, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Donna L Gruol
- Molecular and Cellular Neuroscience Department, The Scripps Research Institute, La Jolla, CA 92037, USA.
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N'Gouemo P. Voltage-Sensitive Calcium Channels in the Brain: Relevance to Alcohol Intoxication and Withdrawal. Handb Exp Pharmacol 2018; 248:263-280. [PMID: 29500720 DOI: 10.1007/164_2018_93] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Voltage-sensitive Ca2+ (CaV) channels are the primary route of depolarization-induced Ca2+ entry in neurons and other excitable cells, leading to an increase in intracellular Ca2+ concentration ([Ca2+]i). The resulting increase in [Ca2+]i activates a wide range of Ca2+-dependent processes in neurons, including neurotransmitter release, gene transcription, activation of Ca2+-dependent enzymes, and activation of certain K+ channels and chloride channels. In addition to their key roles under physiological conditions, CaV channels are also an important target of alcohol, and alcohol-induced changes in Ca2+ signaling can disturb neuronal homeostasis, Ca2+-mediated gene transcription, and the function of neuronal circuits, leading to various neurological and/or neuropsychiatric symptoms and disorders, including alcohol withdrawal induced-seizures and alcoholism.
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Affiliation(s)
- Prosper N'Gouemo
- Department of Pediatrics, Georgetown University Medical Center, Washington, DC, USA.
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Rinker JA, Fulmer DB, Trantham-Davidson H, Smith ML, Williams RW, Lopez MF, Randall PK, Chandler LJ, Miles MF, Becker HC, Mulholland PJ. Differential potassium channel gene regulation in BXD mice reveals novel targets for pharmacogenetic therapies to reduce heavy alcohol drinking. Alcohol 2017; 58:33-45. [PMID: 27432260 DOI: 10.1016/j.alcohol.2016.05.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 04/12/2016] [Accepted: 05/03/2016] [Indexed: 12/22/2022]
Abstract
Alcohol (ethanol) dependence is a chronic relapsing brain disorder partially influenced by genetics and characterized by an inability to regulate harmful levels of drinking. Emerging evidence has linked genes that encode KV7, KIR, and KCa2 K+ channels with variation in alcohol-related behaviors in rodents and humans. This led us to experimentally test relations between K+ channel genes and escalation of drinking in a chronic-intermittent ethanol (CIE) exposure model of dependence in BXD recombinant inbred strains of mice. Transcript levels for K+ channel genes in the prefrontal cortex (PFC) and nucleus accumbens (NAc) covary with voluntary ethanol drinking in a non-dependent cohort. Transcripts that encode KV7 channels covary negatively with drinking in non-dependent BXD strains. Using a pharmacological approach to validate the genetic findings, C57BL/6J mice were allowed intermittent access to ethanol to establish baseline consumption before they were treated with retigabine, an FDA-approved KV7 channel positive modulator. Systemic administration significantly reduced drinking, and consistent with previous evidence, retigabine was more effective at reducing voluntary consumption in high-drinking than low-drinking subjects. We evaluated the specific K+ channel genes that were most sensitive to CIE exposure and identified a gene subset in the NAc and PFC that were dysregulated in the alcohol-dependent BXD cohort. CIE-induced modulation of nine genes in the NAc and six genes in the PFC covaried well with the changes in drinking induced by ethanol dependence. Here we identified novel candidate genes in the NAc and PFC that are regulated by ethanol dependence and correlate with voluntary drinking in non-dependent and dependent BXD mice. The findings that Kcnq expression correlates with drinking and that retigabine reduces consumption suggest that KV7 channels could be pharmacogenetic targets to treat individuals with alcohol addiction.
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Spencer KB, Mulholland PJ, Chandler LJ. FMRP Mediates Chronic Ethanol-Induced Changes in NMDA, Kv4.2, and KChIP3 Expression in the Hippocampus. Alcohol Clin Exp Res 2016; 40:1251-61. [PMID: 27147118 DOI: 10.1111/acer.13060] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 03/04/2016] [Indexed: 11/30/2022]
Abstract
BACKGROUND Exposure to chronic ethanol (EtOH) results in changes in the expression of proteins that regulate neuronal excitability. This study examined whether chronic EtOH alters the hippocampal expression and function of fragile X mental retardation protein (FMRP) and the role of FMRP in the modulation of chronic EtOH-induced changes in the expression of NMDA receptors and Kv4.2 channels. METHODS For in vivo studies, C57BL/6J mice underwent a chronic intermittent EtOH (CIE) vapor exposure procedure. After CIE, hippocampal tissue was collected and subjected to immunoblot blot analysis of NMDA receptor subunits (GluN1, GluN2B), Kv4.2, and its accessory protein KChIP3. For in vitro studies, hippocampal slice cultures were exposed to 75 mM EtOH for 8 days. Following EtOH exposure, mRNAs bound to FMRP was measured. In a separate set of studies, cultures were exposed to an inhibitor of S6K1 (PF-4708671 [PF], 6 μM) in order to assess whether EtOH-induced homeostatic changes in protein expression depend upon changes in FMRP activity. RESULTS Immunoblot blot analysis revealed increases in GluN1 and GluN2B but reductions in Kv4.2 and KChIP3. Analysis of mRNAs bound to FMRP revealed a similar bidirectional change observed as reduction of GluN2B and increase in Kv4.2 and KChIP3 mRNA transcripts. Analysis of FMRP further revealed that while chronic EtOH did not alter the expression of FMRP, it significantly increased phosphorylation of FMRP at the S499 residue that is known to critically regulate its activity. Inhibition of S6K1 prevented the chronic EtOH-induced increase in phospho-FMRP and changes in NMDA subunits, Kv4.2, and KChIP3. In contrast, PF had no effect in the absence of alcohol, indicating it was specific for the chronic EtOH-induced changes. CONCLUSIONS These findings demonstrate that chronic EtOH exposure enhances translational control of plasticity-related proteins by FMRP, and that S6K1 and FMRP activities are required for expression of chronic EtOH-induced homeostatic plasticity at glutamatergic synapses in the hippocampus.
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Affiliation(s)
- Kathryn B Spencer
- Department of Neurosciences, Medical University of South Carolina, Charleston, South Carolina
| | - Patrick J Mulholland
- Department of Neurosciences, Medical University of South Carolina, Charleston, South Carolina
| | - L Judson Chandler
- Department of Neurosciences, Medical University of South Carolina, Charleston, South Carolina
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Burnett EJ, Chandler LJ, Trantham-Davidson H. Glutamatergic plasticity and alcohol dependence-induced alterations in reward, affect and cognition. Prog Neuropsychopharmacol Biol Psychiatry 2016; 65:309-20. [PMID: 26341050 PMCID: PMC4679411 DOI: 10.1016/j.pnpbp.2015.08.012] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2015] [Revised: 07/29/2015] [Accepted: 08/27/2015] [Indexed: 12/21/2022]
Abstract
INTRODUCTION Alcohol dependence is characterized by a reduction in reward threshold, development of a negative affective state, and significant cognitive impairments. Dependence-induced glutamatergic neuroadaptations in the neurocircuitry mediating reward, affect and cognitive function are thought to underlie the neural mechanism for these alterations. These changes serve to promote increased craving for alcohol and facilitate the development of maladaptive behaviors that promote relapse to alcohol drinking during periods of abstinence. OBJECTIVE To review the extant literature on the effects of chronic alcohol exposure on glutamatergic neurotransmission and its impact on reward, affect and cognition. RESULTS Evidence from a diverse set of studies demonstrates significant enhancement of glutamatergic activity following chronic alcohol exposure. In particular, up-regulation of GluN2B-containing NMDA receptor expression and function is a commonly observed phenomenon that likely reflects activity-dependent adaptive homeostatic plasticity. However, this observation as well as other glutamatergic neuroadaptations are often circuit and cell-type specific. DISCUSSION Dependence-induced alterations in glutamate signaling contribute to many of the symptoms experienced in addicted individuals and can persist well into abstinence. This suggests that they play an important role in the development of behaviors that increase the probability for relapse. As our understanding of the complexity of the neurocircuitry involved in the addictive process has advanced, it has become increasingly clear that investigations of cell-type and circuit-specific effects are required to gain a more comprehensive understanding of the glutamatergic adaptations and their functional consequences in alcohol addiction. CONCLUSION While pharmacological treatments for alcohol dependence and relapse targeting the glutamatergic system have shown great promise in preclinical models, more research is needed to uncover novel, possibly circuit-specific, therapeutic targets that exhibit improved efficacy and reduced side effects.
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Affiliation(s)
- Elizabeth J Burnett
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC 29425.
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Hernandez RV, Puro AC, Manos JC, Huitron-Resendiz S, Reyes KC, Liu K, Vo K, Roberts AJ, Gruol DL. Transgenic mice with increased astrocyte expression of IL-6 show altered effects of acute ethanol on synaptic function. Neuropharmacology 2015; 103:27-43. [PMID: 26707655 DOI: 10.1016/j.neuropharm.2015.12.015] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Revised: 11/21/2015] [Accepted: 12/14/2015] [Indexed: 11/29/2022]
Abstract
A growing body of evidence has revealed that resident cells of the central nervous system (CNS), and particularly the glial cells, comprise a neuroimmune system that serves a number of functions in the normal CNS and during adverse conditions. Cells of the neuroimmune system regulate CNS functions through the production of signaling factors, referred to as neuroimmune factors. Recent studies show that ethanol can activate cells of the neuroimmune system, resulting in the elevated production of neuroimmune factors, including the cytokine interleukin-6 (IL-6). Here we analyzed the consequences of this CNS action of ethanol using transgenic mice that express elevated levels of IL-6 through increased astrocyte expression (IL-6-tg) to model the increased IL-6 expression that occurs with ethanol use. Results show that increased IL-6 expression induces neuroadaptive changes that alter the effects of ethanol. In hippocampal slices from non-transgenic (non-tg) littermate control mice, synaptically evoked dendritic field excitatory postsynaptic potential (fEPSP) and somatic population spike (PS) at the Schaffer collateral to CA1 pyramidal neuron synapse were reduced by acute ethanol (20 or 60 mM). In contrast, acute ethanol enhanced the fEPSP and PS in hippocampal slices from IL-6 tg mice. Long-term synaptic plasticity of the fEPSP (i.e., LTP) showed the expected dose-dependent reduction by acute ethanol in non-tg hippocampal slices, whereas LTP in the IL-6 tg hippocampal slices was resistant to this depressive effect of acute ethanol. Consistent with altered effects of acute ethanol on synaptic function in the IL-6 tg mice, EEG recordings showed a higher level of CNS activity in the IL-6 tg mice than in the non-tg mice during the period of withdrawal from an acute high dose of ethanol. These results suggest a potential role for neuroadaptive effects of ethanol-induced astrocyte production of IL-6 as a mediator or modulator of the actions of ethanol on the CNS, including persistent changes in CNS function that contribute to cognitive dysfunction and the development of alcohol dependence.
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Affiliation(s)
- Ruben V Hernandez
- Molecular and Cellular Neuroscience Department, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Alana C Puro
- Molecular and Cellular Neuroscience Department, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Jessica C Manos
- Molecular and Cellular Neuroscience Department, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Salvador Huitron-Resendiz
- Molecular and Cellular Neuroscience Department, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Kenneth C Reyes
- Molecular and Cellular Neuroscience Department, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Kevin Liu
- Molecular and Cellular Neuroscience Department, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Khanh Vo
- Molecular and Cellular Neuroscience Department, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Amanda J Roberts
- Molecular and Cellular Neuroscience Department, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Donna L Gruol
- Molecular and Cellular Neuroscience Department, The Scripps Research Institute, La Jolla, CA 92037, USA.
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