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Alberto GE, Klorig DC, Goldstein AT, Godwin DW. Alcohol withdrawal produces changes in excitability, population discharge probability, and seizure threshold. ALCOHOL, CLINICAL & EXPERIMENTAL RESEARCH 2023; 47:211-218. [PMID: 36543333 PMCID: PMC10197957 DOI: 10.1111/acer.15004] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 12/15/2022] [Accepted: 12/19/2022] [Indexed: 12/24/2022]
Abstract
BACKGROUND Alcohol withdrawal syndrome (AWS) results from the sudden cessation of chronic alcohol use and is associated with high morbidity and mortality. Alcohol withdrawal-induced central nervous system (CNS) hyperexcitability results from complex, compensatory changes in synaptic efficacy and intrinsic excitability. These changes in excitability counteract the depressing effects of chronic ethanol on neural transmission and underlie symptoms of AWS, which range from mild anxiety to seizures and death. The development of targeted pharmacotherapies for treating AWS has been slow, due in part to the lack of available animal models that capture the key features of human AWS. Using a unique optogenetic method of probing network excitability, we examined electrophysiologic correlates of hyperexcitability sensitive to early changes in CNS excitability. This method is sensitive to pharmacologic treatments that reduce excitability and may represent a platform for AWS drug development. METHODS We applied a newly developed method, the optogenetic population discharge threshold (oPDT), which uses light intensity response curves to measure network excitability in chronically implanted mice. Excitability was tracked using the oPDT before, during, and after the chronic intermittent exposure (CIE) model of alcohol withdrawal (WD). RESULTS Alcohol withdrawal produced a dose-dependent leftward shift in the oPDT curve (denoting increased excitability), which was detectable in as few as three exposure cycles. This shift in excitability mirrored an increase in the number of spontaneous interictal spikes during withdrawal. In addition, Withdrawal lowered seizure thresholds and increased seizure severity in optogenetically kindled mice. CONCLUSION We demonstrate that the oPDT provides a sensitive measure of alcohol withdrawal-induced hyperexcitability. The ability to actively probe the progression of excitability without eliciting potentially confounding seizures promises to be a useful tool in the preclinical development of next-generation pharmacotherapies for AWS.
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Affiliation(s)
- Gregory E. Alberto
- Wake Forest School of Medicine; Department of Neurobiology and Anatomy; Winston-Salem, NC, USA
- Wake Forest School of Medicine; Department of Neurology; Winston-Salem, NC, USA
- Dartmouth-Hitchcock Medical Center; Department of Psychiatry; Lebanon, NH, USA
| | - David C. Klorig
- Wake Forest School of Medicine; Department of Neurobiology and Anatomy; Winston-Salem, NC, USA
- Wake Forest School of Medicine; Department of Neurology; Winston-Salem, NC, USA
- Wake Forest School of Medicine; Department of Physiology and Pharmacology; Winston-Salem, NC, USA
| | - Allison T. Goldstein
- Wake Forest School of Medicine; Department of Neurobiology and Anatomy; Winston-Salem, NC, USA
| | - Dwayne W. Godwin
- Wake Forest School of Medicine; Department of Neurobiology and Anatomy; Winston-Salem, NC, USA
- Wake Forest School of Medicine; Department of Neurology; Winston-Salem, NC, USA
- Research and Education Department, W.G. (Bill) Hefner Veterans Affairs Medical Center; Salisbury, NC, USA
- Wake Forest School of Medicine; Department of Physiology and Pharmacology; Winston-Salem, NC, USA
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Akinfiresoye LR, Newton J, Suman S, Datta K, N'Gouemo P. Targeted Inhibition of Upregulated Sodium-Calcium Exchanger in Rat Inferior Colliculus Suppresses Alcohol Withdrawal Seizures. Mol Neurobiol 2023; 60:292-302. [PMID: 36264435 PMCID: PMC10577795 DOI: 10.1007/s12035-022-03072-2] [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: 04/08/2022] [Accepted: 10/08/2022] [Indexed: 11/29/2022]
Abstract
The inferior colliculus (IC) is critical in initiating acoustically evoked alcohol withdrawal-induced seizures (AWSs). Recently, we reported that systemic inhibition of Ca2+ entry via the reverse mode activity of the Na+/Ca2+ exchanger (NCXrev) suppressed AWSs, suggesting remodeling of NCX expression and function, at least in the IC, the site of AWS initiation. Here, we probe putative changes in protein expression in the IC of NCX isoforms, including NCX type 1 (NCX1), 2 (NCX2), and 3 (NCX3). We also evaluated the efficacy of targeted inhibition of NCX1rev and NCX3rev activity in the IC on the occurrence and severity of AWSs using SN-6 and KB-R943, respectively. We used our well-characterized alcohol intoxication/withdrawal model associated with enhanced AWS susceptibility. IC tissues from the alcohol-treated group were collected 3 h (before the onset of AWS susceptibility), 24 h (when AWS susceptibility is maximal), and 48 h (when AWS susceptibility is resolved) following alcohol withdrawal; in comparison, IC tissues from the control-treated group were collected at 24 h after the last gavage. Analysis shows that NCX1 protein levels were markedly higher 3 and 24 h following alcohol withdrawal. However, NCX3 protein levels were only higher 3 h following alcohol withdrawal. The analysis also reveals that bilateral microinjections of SN-6 (but not KB-R7943) within the IC markedly suppressed the occurrence and severity of AWSs. Together, these findings indicate that NCX1 is a novel molecular target that may play an essential role in the pathogenesis and pathophysiology of AWSs.
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Affiliation(s)
- Luli R Akinfiresoye
- Department of Physiology and Biophysics, Howard University College of Medicine, Suite 2420, 520 W Street, NW, Washington, DC, 20059, USA
- Diversion Control Division, Drug Enforcement Administration, United States Department of Justice, Springfield, VA, USA
| | - Jamila Newton
- Department of Physiology and Biophysics, Howard University College of Medicine, Suite 2420, 520 W Street, NW, Washington, DC, 20059, USA
- California State University, Stanislaus, Turlock, CA, USA
| | - Shubhankar Suman
- Oncology and Department of Biochemistry and Molecular & Cellular Biology, Georgetown Lombardi Comprehensive Cancer Center (LCCC), Washington, DC, USA
| | - Kamal Datta
- Oncology and Department of Biochemistry and Molecular & Cellular Biology, Georgetown Lombardi Comprehensive Cancer Center (LCCC), Washington, DC, USA
| | - Prosper N'Gouemo
- Department of Physiology and Biophysics, Howard University College of Medicine, Suite 2420, 520 W Street, NW, Washington, DC, 20059, USA.
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Maxson SC. A genetic context for the study of audiogenic seizures. Epilepsy Behav 2017; 71:154-159. [PMID: 26907925 DOI: 10.1016/j.yebeh.2015.12.031] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Accepted: 12/26/2015] [Indexed: 11/28/2022]
Abstract
Here, the genetic context for the study of audiogenic seizures is four single-gene, spontaneous mutations that occurred in the Behavior Genetics Laboratory at the University of Chicago from 1959 to 1969. Three of these increased the incidence of audiogenic seizures, and one of these decreased the incidence of audiogenic seizures. The genetics of one of these mutants is described in detail, and the effect of diet on the same mutant is also described in detail. Research on genetic and environmental effects on the cortical EEG of audiogenic seizures is reviewed; this research included two of these mutants. The cortical EEG associated with audiogenic seizures in this study was consistent with audiogenic seizures being a type of brain stem epilepsy as had been proposed by others. Also, I proposed that brain stem pathophysiology is the same regardless of the genetic or environmental pathway to audiogenic seizure susceptibility. Research is also reviewed using these mutants to determine whether or not a strain association between glutamic acid decarboxylase (GAD) activity in whole brain and susceptibility to audiogenic seizures is pleiotropic and whether or not a strain association between nucleoside triphosphatase (NTPase) activity in the granule cell layer of the dentate fascia of the hippocampus and susceptibility to audiogenic seizures is a lineal or collateral pleiotropy. Lastly, pleiotropy as an explanation for strain comorbidities in aggressive behavior and audiogenic seizures is considered. This article is part of a Special Issue entitled "Genetic and Reflex Epilepsies, Audiogenic Seizures and Strains: From Experimental Models to the Clinic".
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Affiliation(s)
- Stephen C Maxson
- Department of Psychology, The University of Connecticut, Storrs, CT 06269-1020, USA.
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Cheaha D, Sawangjaroen K, Kumarnsit E. Characterization of fluoxetine effects on ethanol withdrawal-induced cortical hyperexcitability by EEG spectral power in rats. Neuropharmacology 2014; 77:49-56. [DOI: 10.1016/j.neuropharm.2013.09.020] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Revised: 08/18/2013] [Accepted: 09/16/2013] [Indexed: 11/29/2022]
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Vasudevan A, Ho MSP, Weiergräber M, Nischt R, Schneider T, Lie A, Smyth N, Köhling R. Basement membrane protein nidogen-1 shapes hippocampal synaptic plasticity and excitability. Hippocampus 2010; 20:608-20. [PMID: 19530222 DOI: 10.1002/hipo.20660] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The basement membrane (BM) is a specialized form of extracellular matrix (ECM) underlying epithelia and endothelia and surrounding many types of mesenchymal cells. Nidogen, along with collagen IV and laminin, is a major component of BMs. Although certain ECM proteins such as laminin or reelin influence neuronal function via interactions with cell-surface receptors such as integrins, behavioral neurological impairments due to deficits of BM components have been recognized only recently. Here, alterations in neuronal network function underlying these behavioral changes are revealed. Using nidogen-1 knockout mice, with or without additional heterozygous nidogen-2 knockout (NID1(-/-)/NID2(+/+) or NID1(-/-)/NID2(+/-)), we demonstrate that nidogen is essential for normal neuronal network excitability and plasticity. In nidogen-1 knockouts, seizurelike behavior occurs, and epileptiform spiking was seen in hippocampal in vivo EEG recordings. In vitro, hippocampal field potential recordings revealed that lack of nidogen-1, while not causing conspicuous morphological changes, led to the appearance of spontaneous and evoked epileptiform activity, significant increase of the input/output ratio of synaptically evoked responses in CA1 and dentate gyrus, as well as of paired pulse accentuation, and loss of perforant-path long-term synaptic potentiation. Nidogen-1 is thus essential for normal network excitability and plasticity.
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Affiliation(s)
- Anju Vasudevan
- Center for Biochemistry and Center for Molecular Medicine Cologne, University of Cologne, Joseph-Stelzmann-Str. 52, 50931 Köln, Germany
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Abstract
Abrupt cessation of alcohol intake after prolonged heavy drinking may trigger alcohol withdrawal seizures. Generalized tonic-clonic seizures are the most characteristic and severe type of seizure that occur in this setting. Generalized seizures also occur in rodent models of alcohol withdrawal. In these models, the withdrawal seizures are triggered by neuronal networks in the brainstem, including the inferior colliculus; similar brainstem mechanisms may contribute to alcohol withdrawal seizures in humans. Alcohol causes intoxication through effects on diverse ion channels and neurotransmitter receptors, including GABA(A) receptors--particularly those containing delta subunits that are localized extrasynaptically and mediate tonic inhibition--and N-methyl-D-aspartate (NMDA) receptors. Alcohol dependence results from compensatory changes during prolonged alcohol exposure, including internalization of GABA(A) receptors, which allows adaptation to these effects. Withdrawal seizures are believed to reflect unmasking of these changes and may also involve specific withdrawal-induced cellular events, such as rapid increases in alpha4 subunit-containing GABA(A) receptors that confer reduced inhibitory function. Optimizing approaches to the prevention of alcohol withdrawal seizures requires an understanding of the distinct neurobiologic mechanisms that underlie these seizures.
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Affiliation(s)
- Michael A Rogawski
- Epilepsy Research Section, Porter Neuroscience Research Center, NINDS, NIH, Bethesda, MD20892-3702, USA.
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Veatch LM, Gonzalez LP. Repeated Ethanol Withdrawal Delays Development of Focal Seizures in Hippocampal Kindling. Alcohol Clin Exp Res 1999. [DOI: 10.1111/j.1530-0277.1999.tb04271.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Sokomba E, Osuide G. Influence of acute and chronic administration of ethanol on photic-evoked response in rats. JAPANESE JOURNAL OF PHARMACOLOGY 1985; 39:285-90. [PMID: 4094178 DOI: 10.1254/jjp.39.285] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The effect of acute and chronic administration of ethanol on photic-evoked response was studied in rats. Acute administration of ethanol (1-3 g/kg, i.p.) produced behavioural depression, EEG synchronization and a biphasic effect on the amplitude of the photic evoked responses (PER) recorded from the frontal cortex (FC) and optic cortex (OC), while a reduction in amplitude was observed in the midbrain reticular formation (MBRF). The amplitude of the averaged PER in the FC and OC was increased in chronic ethanol-treated rats, while in the MBRF, a reduction in amplitude was observed. Abrupt discontinuation of ethanol produced behavioural excitation and increase in amplitude of the averaged evoked responses recorded from the three brain areas studied. These observations suggest that the neural hyperexcitability that characterizes ethanol withdrawal may affect both cortical and subcortical structures.
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Hunter BE, Boast CA, Walker DW, Zornetzer SF, Riley JN. Ethanol dependence in the rat: role of non-specific and limbic regions in the withdrawal reaction. ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY 1978; 45:483-95. [PMID: 81750 DOI: 10.1016/0013-4694(78)90292-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Chronic bipolar electrodes were implanted in cortical, limbic, diencephalic and mesencephalic regions of the rat. Following recovery from surgery the rats were maintained for 14--26 days on a liquid diet in which 35--42% of total calories were provided by ethanol. Following ethanol withdrawal, electrographic and behavioral monitoring was continued for 8--10 h. The withdrawal of ethanol resulted in the time-dependent appearance of a variety of withdrawal signs including tail arching, ataxia, rigidity, tremor and spontaneous and audiogenic convulsions. These behavioral signs were accompanied by the development of epileptiform abnormalities across wide-spread brain regions. Analysis of preconvulsive spike activity revealed a greater spike frequency in limbic, mesencephalic and non-specific diencephalic regions, as compared to those in cortex and specific diencephalon. Seizure discharge during the tonic-clonic phase of the primary audiogenic convulsion was initiated in the mesencephalon or amygdala, but spread rather extensively to the remainder of the brain. In those instances, however, where multiple convulsions occurred following the audiogenic convulsions, there was a marked decline in spread of seizure discharge to the cortex. These results were interpreted to support the notion that some degree of neuroanatomical specificity exists in the genesis of epileptiform abnormalities during ethanol withdrawal. A comparison of these results with those studying the neural mechanisms underlying other forms of generalized epilepsy was made. It is hypothesized that central pacemaking regions such as medial thalamus or reticular formation may serve to organize isolated epileptiform activity into coherent patterns of paroxysmal activity throughout the brain during the ethanol withdrawal syndrome.
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Abstract
In mice chronically treated with ethanol (in a liquid diet containing 6% ethanol ad libitum for 2 weeks), brain tryptophan hydroxylase (TPH) activity was increased (by 30-45% in whole brain), while brain tyrosine hydroxylase activity remained unchanged. Such chronic ethanol treatment also induced susceptibility to audiogenic seizures during withdrawal (60% incidence). When ethanol treatment was given to adrenalectomized (Adx) mice, the increase of brain TPH activity and the development of withdrawal audiogenic seizures were both prevented. In Adx mice receiving daily injections of corticosterone (0.5 mg/mouse), the ethanol-induced increase of brain TPH activity and the occurrence of withdrawal audiogenic seizures were both restored. Similarly, the ethanol-induced increase of liver alcohol dehydrogenase activity (by 60%) was prevented in Adx mice and restored by corticosterone replacement. It was noted that in all three cases replacement with such large doses of the corticoid did not enhance the ethanol effects, but merely restored the effects to the levels observed in intact mice. Apparently, glucocorticoids are required in a permissive role in order for the ethanol effects to occur.
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