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Jung ME, Mallet RT. Intermittent hypoxia training: Powerful, non-invasive cerebroprotection against ethanol withdrawal excitotoxicity. Respir Physiol Neurobiol 2018; 256:67-78. [PMID: 28811138 PMCID: PMC5825251 DOI: 10.1016/j.resp.2017.08.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2017] [Revised: 07/24/2017] [Accepted: 08/08/2017] [Indexed: 12/12/2022]
Abstract
Ethanol intoxication and withdrawal exact a devastating toll on the central nervous system. Abrupt ethanol withdrawal provokes massive release of the excitatory neurotransmitter glutamate, which over-activates its postsynaptic receptors, causing intense Ca2+ loading, p38 mitogen activated protein kinase activation and oxidative stress, culminating in ATP depletion, mitochondrial injury, amyloid β deposition and neuronal death. Collectively, these mechanisms produce neurocognitive and sensorimotor dysfunction that discourages continued abstinence. Although the brain is heavily dependent on blood-borne O2 to sustain its aerobic ATP production, brief, cyclic episodes of moderate hypoxia and reoxygenation, when judiciously applied over the course of days or weeks, evoke adaptations that protect the brain from ethanol withdrawal-induced glutamate excitotoxicity, mitochondrial damage, oxidative stress and amyloid β accumulation. This review summarizes evidence from ongoing preclinical research that demonstrates intermittent hypoxia training to be a potentially powerful yet non-invasive intervention capable of affording robust, sustained neuroprotection during ethanol withdrawal.
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Affiliation(s)
- Marianna E Jung
- Center for Neuroscience Discovery, University of North Texas Health Science Center, 3500 Camp Bowie Boulevard, Fort Worth, TX 76107-2699, USA.
| | - Robert T Mallet
- Institute for Cardiovascular and Metabolic Diseases, University of North Texas Health Science Center, 3500 Camp Bowie Boulevard, Fort Worth, TX 76107-2699, USA.
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Masicampo ML, Shan HQ, Xu V, Speagle M, Godwin DW. Selective Blockade of T-Type Ca2+ Channels is Protective Against Alcohol-Withdrawal Induced Seizure and Mortality. Alcohol Alcohol 2018; 53:526-531. [PMID: 29912275 DOI: 10.1093/alcalc/agy042] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 06/04/2018] [Indexed: 11/13/2022] Open
Abstract
AIMS We have previously demonstrated that blockade of T-type calcium channels by the non-selective antagonist, ethosuximide (ETX), is effective at reducing electrographical and behavioral correlates of alcohol-withdrawal (WD) seizure. Here, we investigated whether blockade of these calcium channels with the selective antagonist TTA-P2 also reduces alcohol-WD seizure. SHORT SUMMARY The non-specific T-type calcium channel antagonist, ETX, is protective against alcohol-WD seizure. However, the mechanism of this effect is unclear. Here, we provide evidence that further suggests selective blockade of T-type calcium channels are protective against alcohol-WD seizure and WD-related mortality. METHODS We used an intermittent ethanol exposure model to produce WD-induced hyperexcitability in DBA/2 J mice. Seizure severity was intensified with the chemoconvulsant pentylenetetrazole (PTZ). RESULTS TTA-P2 (10 mg/kg) reduced seizure severity in mice undergoing alcohol WD with concurrent PTZ treatment (20 mg/kg). Moreover, TTA-P2 (20 and 40 mg/kg) was also protective against PTZ-induced (40 mg/kg) seizure and mortality. CONCLUSIONS These results are consistent with prior results using ETX, and suggest that the protective effects of ETX and TTA-P2 against EtOH WD seizures are mediated by T-type calcium channels.
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Affiliation(s)
- Melissa L Masicampo
- Department of Neurobiology and Anatomy, Wake Forest University School of Medicine, 1 Medical Center Boulevard, Winston-Salem, NC, USA.,Department of Physiology and Pharmacology, Wake Forest School of Medicine, 1 Medical Center Boulevard, Winston-Salem, NC, USA
| | - Hong Qu Shan
- Department of Neurobiology and Anatomy, Wake Forest University School of Medicine, 1 Medical Center Boulevard, Winston-Salem, NC, USA
| | - Victoria Xu
- Department of Neurobiology and Anatomy, Wake Forest University School of Medicine, 1 Medical Center Boulevard, Winston-Salem, NC, USA
| | - Merritt Speagle
- Department of Neurobiology and Anatomy, Wake Forest University School of Medicine, 1 Medical Center Boulevard, Winston-Salem, NC, USA
| | - Dwayne W Godwin
- Department of Neurobiology and Anatomy, Wake Forest University School of Medicine, 1 Medical Center Boulevard, Winston-Salem, NC, USA.,Department of Physiology and Pharmacology, Wake Forest School of Medicine, 1 Medical Center Boulevard, Winston-Salem, NC, USA
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Gruol DL, Huitron-Resendiz S, Roberts AJ. Altered brain activity during withdrawal from chronic alcohol is associated with changes in IL-6 signal transduction and GABAergic mechanisms in transgenic mice with increased astrocyte expression of IL-6. Neuropharmacology 2018; 138:32-46. [PMID: 29787738 DOI: 10.1016/j.neuropharm.2018.05.024] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Revised: 04/25/2018] [Accepted: 05/17/2018] [Indexed: 10/16/2022]
Abstract
Interleukin-6 (IL-6) is an important neuroimmune factor that is increased in the brain by alcohol exposure/withdrawal and is thought to play a role in the actions of alcohol on the brain. To gain insight into IL-6/alcohol/withdrawal interactions and how these interactions affect the brain, we are studying the effects of chronic binge alcohol exposure on transgenic mice that express elevated levels of IL-6 in the brain due to increased astrocyte expression (IL-6 tg) and their non-transgenic (non-tg) littermate controls. IL-6/alcohol/withdrawal interactions were identified by genotypic differences in spontaneous brain activity in electroencephalogram (EEG) recordings from the mice, and by Western blot analysis of protein activation or expression in hippocampus obtained from the mice after the final alcohol withdrawal period. Results from EEG studies showed frequency dependent genotypic differences in brain activity during withdrawal. For EEG frequencies that were affected by alcohol exposure/withdrawal in both genotypes, the nature of the effect was similar, but differed across withdrawal cycles. Differences between IL-6 tg and non-tg mice were also observed in Western blot studies of the activated form of STAT3 (phosphoSTAT3), a signal transduction partner of IL-6, and subunits of GABAA receptors (GABAAR). Regression analysis revealed that pSTAT3 played a more prominent role during withdrawal in the IL-6 tg mice than in the non-tg mice, and that the role of GABAAR alpha-5 and GABAAR alpha-1 in brain activity varied across genotype and withdrawal. Taken together, our results suggest that IL-6 can significantly impact mechanisms involved in alcohol withdrawal.
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Affiliation(s)
- Donna L Gruol
- Neuroscience Department, The Scripps Research Institute, La Jolla, CA, 92037, USA.
| | | | - Amanda J Roberts
- Animal Models Core Facility, The Scripps Research Institute, La Jolla, CA, 92037, USA
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Riegle MA, Masicampo ML, Shan HQ, Xu V, Godwin DW. Ethosuximide Reduces Mortality and Seizure Severity in Response to Pentylenetetrazole Treatment During Ethanol Withdrawal. Alcohol Alcohol 2015; 50:501-8. [PMID: 25870316 DOI: 10.1093/alcalc/agv033] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Accepted: 03/12/2015] [Indexed: 11/13/2022] Open
Abstract
AIMS We recently demonstrated that T-type calcium channels are affected by alcohol abuse and withdrawal. Treatment with ethosuximide, an antiepileptic drug that blocks T-type calcium channels, reduces seizure activity induced by intermittent ethanol exposures and withdrawals. Here, we expand on these findings to test whether ethosuximide can reduce the sensitivity to pentylenetetrazole-induced seizures during ethanol withdrawal. METHODS We used an intermittent ethanol exposure model to produce withdrawal-induced hyperexcitability in DBA/2J mice. RESULTS Ethosuximide (250 mg/kg) reduced seizure severity in mice undergoing ethanol withdrawal with concurrent PTZ treatment (20 mg/kg). Importantly, ethosuximide did not produce rebound excitability and protected against ethanol withdrawal-induced mortality produced by concurrent PTZ treatment (40 mg/kg). CONCLUSION These results, in addition to previous preclinical findings, suggest that ethosuximide should be further evaluated as a safe, effective alternative to benzodiazepines for the treatment of alcohol withdrawal.
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Affiliation(s)
- Melissa A Riegle
- Neuroscience Program, Wake Forest School of Medicine Department of Neurobiology and Anatomy, Wake Forest School of Medicine, 1 Medical Center Boulevard, Winston-Salem, NC 27157, USA
| | - Melissa L Masicampo
- Department of Neurobiology and Anatomy, Wake Forest School of Medicine, 1 Medical Center Boulevard, Winston-Salem, NC 27157, USA
| | - Hong Qu Shan
- Department of Neurobiology and Anatomy, Wake Forest School of Medicine, 1 Medical Center Boulevard, Winston-Salem, NC 27157, USA
| | - Victoria Xu
- Department of Neurobiology and Anatomy, Wake Forest School of Medicine, 1 Medical Center Boulevard, Winston-Salem, NC 27157, USA
| | - Dwayne W Godwin
- Neuroscience Program, Wake Forest School of Medicine Department of Neurobiology and Anatomy, Wake Forest School of Medicine, 1 Medical Center Boulevard, Winston-Salem, NC 27157, USA
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Knapp CM, Ciraulo DA, Datta S. Mechanisms underlying sleep-wake disturbances in alcoholism: focus on the cholinergic pedunculopontine tegmentum. Behav Brain Res 2014; 274:291-301. [PMID: 25151622 DOI: 10.1016/j.bbr.2014.08.029] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Revised: 08/11/2014] [Accepted: 08/13/2014] [Indexed: 12/24/2022]
Abstract
Sleep-wake (S-W) disturbances are frequently associated with alcohol use disorders (AUD), occurring during periods of active drinking, withdrawal, and abstinence. These S-W disturbances can persist after months or even years of abstinence, suggesting that chronic alcohol consumption may have enduring negative effects on both homeostatic and circadian sleep processes. It is now generally accepted that S-W disturbances in alcohol-dependent individuals are a significant cause of relapse in drinking. Although significant progress has been made in identifying the socio-economic burden and health risks of alcohol addiction, the underlying neurobiological mechanisms that lead to S-W disorders in AUD are poorly understood. Marked progress has been made in understanding the basic neurobiological mechanisms of how different sleep stages are normally regulated. This review article in seeking to explain the neurobiological mechanisms underlying S-W disturbances associated with AUD, describes an evidence-based, easily testable, novel hypothesis that chronic alcohol consumption induces neuroadaptive changes in the cholinergic cell compartment of the pedunculopontine tegmentum (CCC-PPT). These changes include increases in N-methyl-d-aspartate (NMDA) and kainate receptor sensitivity and a decrease in gamma-aminobutyric acid (GABAB)-receptor sensitivity in the CCC-PPT. Together these changes are the primary pathophysiological mechanisms that underlie S-W disturbances in AUD. This review is targeted for both basic neuroscientists in alcohol addiction research and clinicians who are in search of new and more effective therapeutic interventions to treat and/or eliminate sleep disorders associated with AUD.
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Affiliation(s)
- Clifford M Knapp
- Laboratory of Sleep and Cognitive Neuroscience, Boston University Psychiatry Associates Clinical Studies Unit, Department of Psychiatry, Boston University School of Medicine, 85 East Newton Street, Boston, MA 02118, USA
| | - Domenic A Ciraulo
- Laboratory of Sleep and Cognitive Neuroscience, Boston University Psychiatry Associates Clinical Studies Unit, Department of Psychiatry, Boston University School of Medicine, 85 East Newton Street, Boston, MA 02118, USA
| | - Subimal Datta
- Laboratory of Sleep and Cognitive Neuroscience, Boston University Psychiatry Associates Clinical Studies Unit, Department of Psychiatry, Boston University School of Medicine, 85 East Newton Street, Boston, MA 02118, USA.
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Ethosuximide reduces electrographical and behavioral correlates of alcohol withdrawal seizure in DBA/2J mice. Alcohol 2014; 48:445-53. [PMID: 24933286 DOI: 10.1016/j.alcohol.2014.01.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Revised: 01/24/2014] [Accepted: 01/24/2014] [Indexed: 11/20/2022]
Abstract
Chronic alcohol abuse depresses the nervous system and, upon cessation, rebound hyperexcitability can result in withdrawal seizure. Withdrawal symptoms, including seizures, may drive individuals to relapse, thus representing a significant barrier to recovery. Our lab previously identified an upregulation of the thalamic T-type calcium (T channel) isoform CaV3.2 as a potential contributor to the generation and propagation of seizures in a model of withdrawal. In the present study, we examined whether ethosuximide (ETX), a T-channel antagonist, could decrease the severity of ethanol withdrawal seizures by evaluating electrographical and behavioral correlates of seizure activity. DBA/2J mice were exposed to an intermittent ethanol exposure paradigm. Mice were treated with saline or ETX in each withdrawal period, and cortical EEG activity was recorded to determine seizure severity. We observed a progression in seizure activity with each successive withdrawal period. Treatment with ETX reduced ethanol withdrawal-induced spike and wave discharges (SWDs), in terms of absolute number, duration of events, and contribution to EEG power in the 6-10 Hz frequency range. We also evaluated the effects of ETX on handling-induced convulsions. Overall, we observed a decrease in handling-induced convulsion severity in mice treated with ETX. Our findings suggest that ETX may be a useful pharmacological agent for studies of alcohol withdrawal and treatment of resulting seizures.
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Abstract
Alcohol dependence encompasses a serious medical and societal problem that constitutes a major public health concern. A serious consequence of dependence is the emergence of symptoms associated with the alcohol withdrawal syndrome when drinking is abruptly terminated or substantially reduced. Clinical features of alcohol withdrawal include signs of central nervous system hyperexcitability, heightened autonomic nervous system activation, and a constellation of symptoms contributing to psychologic discomfort and negative affect. The development of alcohol dependence is a complex and dynamic process that ultimately reflects a maladaptive neurophysiologic state. Perturbations in a wide range of neurochemical systems, including glutamate, γ-aminobutyric acid, monoamines, a host of neuropeptide systems, and various ion channels produced by the chronic presence of alcohol ultimately compromise the functional integrity of the brain. These neuroadaptations not only underlie the emergence and expression of many alcohol withdrawal symptoms, but also contribute to enhanced relapse vulnerability as well as perpetuation of uncontrolled excessive drinking. This chapter highlights the hallmark features of the alcohol withdrawal syndrome, and describes neuroadaptations in a wide array of neurotransmitter and neuromodulator systems (amino acid and monoamine neurotransmitter, neuropeptide systems, and various ion channels) as they relate to the expression of various signs and symptoms of alcohol withdrawal, as well as their relationship to the significant clinical problem of relapse and uncontrolled dangerous drinking.
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