1
|
Shan HQ, Smith T, Klorig DC, Godwin DW. Protein kinase C epsilon-mediated modulation of T-type calcium channels underlies alcohol withdrawal hyperexcitability in the midline thalamus. ALCOHOL, CLINICAL & EXPERIMENTAL RESEARCH 2024. [PMID: 38740544 DOI: 10.1111/acer.15342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 04/05/2024] [Accepted: 04/17/2024] [Indexed: 05/16/2024]
Abstract
BACKGROUND Millions of people struggle with alcohol use disorder (AUD). Abrupt abstinence after a period of chronic alcohol use can precipitate the alcohol withdrawal syndrome (AWS), which includes hyperexcitability and, potentially, seizures. We have shown that T-type Ca2+ channels are novel, sensitive targets of alcohol, an effect that is dependent upon protein kinase C (PKC). The purpose of this study was to (1) understand midline thalamic neuronal hyperexcitability during alcohol withdrawal and its dependence on PKC; (2) characterize T channel functional changes using both current clamp and voltage clamp methods; and (3) determine which PKC isoform may be responsible for alcohol withdrawal (WD) effects. METHODS Whole-cell patch clamp recordings were performed in midline thalamic neurons in brain slices prepared from C57bl/6 mice that underwent chronic intermittent alcohol exposure in a standard vapor chamber model. The recordings were compared to those from air-exposed controls. T-channel inactivation curves and burst responses were acquired through voltage-clamp and current-clamp recordings, respectively. RESULTS Whole-cell voltage clamp recordings of native T-type current exhibited a depolarizing shift in the voltage-dependency of inactivation during alcohol withdrawal compared to air-exposed controls. A PKCε translocation inhibitor peptide mitigated this change. Current clamp recordings demonstrated more spikes per burst during alcohol withdrawal. Consistent with voltage clamp findings, the PKCɛ translocation inhibitor peptide reduced the number of spikes per burst after WD. CONCLUSION We found that alcohol WD produces T channel-mediated hyperexcitability in the midline thalamus, produced in part by a shift in the inactivation curve consistent with greater availability of T current. WD effects on T current inactivation were reduced to control levels by blocking PKCε translocation. Our results demonstrate that PKCε translocation plays an important role in the regulation of alcohol withdrawal-induced hyperexcitability in midline thalamic circuitry.
Collapse
Affiliation(s)
- Hong Qu Shan
- Department of Translational Neuroscience, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA
| | - Thuy Smith
- Department of Translational Neuroscience, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA
| | - David C Klorig
- Department of Translational Neuroscience, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA
| | - Dwayne W Godwin
- Department of Translational Neuroscience, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA
- Department of Neurology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA
| |
Collapse
|
2
|
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.
Collapse
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
| |
Collapse
|
3
|
Yang H, Shan W, Zhu F, Yu T, Fan J, Guo A, Li F, Yang X, Wang Q. C-Fos mapping and EEG characteristics of multiple mice brain regions in pentylenetetrazol-induced seizure mice model. Neurol Res 2019; 41:749-761. [PMID: 31038018 DOI: 10.1080/01616412.2019.1610839] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Purpose: To confirm different local brain activities characterized in pentylenetetrazol (PTZ)-induced seizure model. Methods: we induced seizure response by a single dose of PTZ injection (45 mg/kg, i.p.). Local activity was recorded in different brain regions by EEG in time and c-Fos staining at different time points (0.5 h, 1 h, 2 h, 4 h) after PTZ treatment. Results: EEG recordings showed distinctive features of activation in different brain areas. With the aggravation of behavioral manifestations of seizures, the frequency and amplitude of the discharges on EEG were increasing gradually. The epileptic response on EEG immediately ended after reaching the maximum stage of seizures, followed by a short period of suppression. The labeling of c-Fos was enhanced in the medial prefrontal cortex, the piriform cortex, the amygdala, hippocampal CA1, CA3 and dentate gyrus, but inapparent in the striatum. The most potent changes in c-Fos were observed in cortex, amygdala nuclei, and dentate gyrus. EEG and c-Fos immunolabeling in neuronal activation showed discrepancies in the striatum. For each brain region, the maximum c-Fos labeling was observed at 2 h after injection and diminished at 4 h. The level of c-Fos immunoreactivity was even lower than the control group, which was accompanied by increased labeling of parvalbumin neurons (PVNs). Conclusions: These findings validated PTZ-induced seizure as a seizure model with a specific spatial-temporal profile. Neuronal activity was enhanced and then subsequently inhibited during seizure evolution. Abbreviations: AEDs: anti-epileptic drugs; AF: Alexa Fluor; CA1: Cornu Ammonis area 1; CA3: Cornu Ammonis area 3; DAB, 3: 3P-diaminobenzidine; DAPI: 4',6-diamidino-2-phenylindole; DG: dentate gyrus; EEG: electroencephalogram; GABA: gamma-aminobutyric acid; IEG: immediate early gene; mPFC: medial prefrontal cortex; NAc: nucleus accumbens; PB: phosphate buffer; PBS: phosphate buffered saline; PBST: phosphate buffered saline with Tween; PFA, paraformaldehyde; PTZ: pentylenetetrazol; PVN: parvalbumin neuron; ROI: regions of interest; SE: status epilepticus.
Collapse
Affiliation(s)
- Huajun Yang
- a Department of Neurology, Beijing Tiantan Hospital, Capital Medical University , Beijing , P.R.China.,b Beijing Institute for Brain Disorders , Beijing , P.R.China.,c National Center for Clinical Medicine of Neurological Diseases , Beijing , P.R.China
| | - Wei Shan
- a Department of Neurology, Beijing Tiantan Hospital, Capital Medical University , Beijing , P.R.China.,b Beijing Institute for Brain Disorders , Beijing , P.R.China.,c National Center for Clinical Medicine of Neurological Diseases , Beijing , P.R.China
| | - Fei Zhu
- a Department of Neurology, Beijing Tiantan Hospital, Capital Medical University , Beijing , P.R.China.,b Beijing Institute for Brain Disorders , Beijing , P.R.China.,c National Center for Clinical Medicine of Neurological Diseases , Beijing , P.R.China
| | - Tingting Yu
- a Department of Neurology, Beijing Tiantan Hospital, Capital Medical University , Beijing , P.R.China.,b Beijing Institute for Brain Disorders , Beijing , P.R.China.,c National Center for Clinical Medicine of Neurological Diseases , Beijing , P.R.China
| | - Jingjing Fan
- a Department of Neurology, Beijing Tiantan Hospital, Capital Medical University , Beijing , P.R.China.,b Beijing Institute for Brain Disorders , Beijing , P.R.China.,c National Center for Clinical Medicine of Neurological Diseases , Beijing , P.R.China
| | - Anchen Guo
- b Beijing Institute for Brain Disorders , Beijing , P.R.China.,c National Center for Clinical Medicine of Neurological Diseases , Beijing , P.R.China
| | - Fei Li
- d Beijing institute of pharmacology and toxicology , Beijing , P.R.China
| | - Xiaofeng Yang
- b Beijing Institute for Brain Disorders , Beijing , P.R.China
| | - Qun Wang
- a Department of Neurology, Beijing Tiantan Hospital, Capital Medical University , Beijing , P.R.China.,b Beijing Institute for Brain Disorders , Beijing , P.R.China.,c National Center for Clinical Medicine of Neurological Diseases , Beijing , P.R.China
| |
Collapse
|
4
|
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.
Collapse
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.
| |
Collapse
|
5
|
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.
Collapse
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
| |
Collapse
|
6
|
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.
Collapse
Affiliation(s)
- Prosper N'Gouemo
- Department of Pediatrics, Georgetown University Medical Center, Washington, DC, USA.
| |
Collapse
|