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Principal Investigator: DWAYNE W GODWIN
Organization: WAKE FOREST UNIVERSITY HEALTH SCIENCES
Fiscal Year: 2022
Award: $429,825
Funding agency: National Institute on Alcohol Abuse and Alcoholism
PROJECT SUMMARY
Alcohol withdrawal (WD) produces a range of dangerous clinical symptoms, including intense seizures.
Hyperexcitability underlying seizures is produced by an array of intrinsic membrane properties that are
disrupted by ethanol (EtOH). Prior work has demonstrated that chronic EtOH exposure and WD produce an
up-regulation of ion channel proteins and a gain of function that promotes WD seizure. A remaining gap in
our understanding of WD-related seizure is a testable model that places cellular changes in a network
context. WD produces upregulation and increased bursting in midline thalamic nuclei. In hippocampus,
mammalian target of rapamycin Complex 1 (mTORC1) is activated in CA1 neurons during WD, represses
translation of Kv1.1, and results in reduced inhibition that we hypothesize will allow invasion of thalamic
bursts and increased epileptiform population discharges. We have developed a new model of network
excitability that will allow us to study the emergence, time course and molecular underpinnings of EtOH WD
hyperexcitability and seizure. We will address the following aims: In Aim 1, we will determine the intrinsic
properties contributing to membrane hyperexcitability in midline thalamus and CA1 due to ethanol WD
seizure. Using voltage clamp recordings in an in vitro preparation coupled with pharmacological approaches,
we will determine whether epileptiform discharges in WD are ultimately dependent on a progressive
imbalance between excitatory burst discharges in thalamus (which depend on PKC), and reduced K+ currents
in CA1 pyramidal cells (which are controlled by mTOR). In Aim 2, we will Determine important regulators of
dendritic excitability in thalamus and CA1 in EtOH WD seizure. mTOR signaling is implicated in the
development of spontaneous seizures in epilepsy, and we show data that it is active during WD. Using
molecular approaches, we will toggle mTOR activity in the presence and absence of protein synthesis
inhibitors. We will test whether mTORC represses translation of Kv1.1, as suggested by our preliminary data.
In Aim 3, we bring together the cellular and molecular findings to determine the effects of WD-mediated
changes to network excitability and seizure susceptibility in vivo. Using a novel optogenetic approach, we will
test whether stimulation of the thalamo-HC pathway during WD will elicit enhanced epileptiform activity
compared to controls that will depend on patterned activity at facilitated CA1 synapses. We expect that
disruptions of mTORC1 will modify or reverse WD-mediated excitability. Seizure threshold is significantly
reduced during repeated EtOH WD and we will use this fact to test the hypothesis that drugs effective against
WD-induced hyper-excitability will also be effective at raising seizure thresholds to baseline levels. Success in
these experiments will provide a more comprehensive understanding of how brief spindle episodes and spike
wave complexes promote or support tonic-clonic WD seizures – which could lead to the identification of novel
pathways and associated drug targets that will provide a means to prevent WD seizure, and to more effectively
treat it.
Terms: <Absolute ethanol><Action Potentials><Address><Alcohol Chemical Class><Alcohol withdrawal syndrome><Alcohols><Ammon Horn><Animal Model><Animal Models and Related Studies><Apical><Behavior><Behavioral><Benzodiazepine Compounds><Benzodiazepines><Brain><Brain Nervous System><Cell Communication and Signaling><Cell Signaling><Chronic><Clinical><Complex><Cornu Ammonis><Coupled><Dangerousness><Data><Dendrites><Dependence><Development><Diagnosis><Dose><Drug Metabolic Detoxication><Drug Metabolic Detoxification><Drug Targeting><Drugs><ETOH><Encephalon><Epilepsy><Epileptic Seizures><Epileptics><Ethanol><Ethyl Alcohol><FK506 Binding Protein 12-Rapamycin Associated Protein 1><FKBP12 Rapamycin Complex Associated Protein 1><FRAP1><FRAP1 gene><FRAP2><Grain Alcohol><Grant><Hippocampus><Hippocampus (Brain)><In Vitro><Incidence><Intracellular Communication and Signaling><Ion Channel Protein><Ion Channel Protein Gene><K channel><Knock-out><Knockout><Knowledge><Lead><Length of Life><Longevity><Mechanistic Target of Rapamycin><Mediating><Medication><Membrane><Messenger RNA><Metabolic Drug Detoxications><Metabolism of Toxic Agents><Methylcarbinol><Midline Nuclear Group><Midline Nuclei of Thalamus><Midline Thalamic Nuclei><Mission><Modeling><Molecular><Mouse Strains><NIH><National Institutes of Health><Nature><Nerve Cells><Nerve Unit><Nervous System Diseases><Neural Cell><Neurocyte><Neurologic Disorders><Neurological Disorders><Neurons><Organism><Outcome><Pathway interactions><Pattern><Pb element><Periventricular Nuclei of Thalamus><Pharmaceutic Preparations><Pharmaceutical Preparations><Pharmacology><Population><Potassium Channel><Potassium Ion Channels><Predisposition><Preparation><Prevention><Procedures><Property><Protein Synthesis Antagonists><Protein Synthesis Inhibitors><Proteins><Public Health><Pyramidal Cells><RAFT1><Rapamune><Rapamycin><Research><Seizure Disorder><Seizures><Signal Transduction><Signal Transduction Systems><Signaling><Sirolimus><Structure><Substance Withdrawal Syndrome><Substance abuse problem><Susceptibility><Symptoms><Synapses><Synaptic><T-Type Calcium Channels><T-Type VDCC><T-Type Voltage-Dependent Calcium Channels><Testing><Thalamic structure><Thalamus><Time><Toxic effect><Toxicities><Transient-Type Calcium Channels><Translations><Transmission><United States National Institutes of Health><Up-Regulation><Upregulation><Withdrawal><Withdrawal Symptom><Withdrawal Syndrome><Work><abuse of substances><addiction liability><addiction potential><alcohol abuse therapy><alcohol abuse treatment><alcohol effect><alcohol exposed><alcohol exposure><alcohol related problem><alcohol treatment><alcohol use disorder><alcohol withdrawal><biological signal transduction><detoxification><developmental><drinking><drug/agent><epilepsia><epileptiform><epileptogenic><ethanol effect><ethanol exposed><ethanol exposure><ethanol use disorder><ethanol withdrawal><experience><experiment><experimental research><experimental study><exposed to alcohol><exposed to ethanol><exposure to alcohol><exposure to ethanol><gain of function><heavy metal Pb><heavy metal lead><hippocampal><improved><in vivo><life span><lifespan><living system><mRNA><mTOR><mammalian target of rapamycin><membrane structure><model of animal><model organism><nervous system disorder><network models><neural cell body><neural circuit><neural circuitry><neurocircuitry><neurological disease><neuronal><neuronal cell body><novel><optogenetics><pathway><prevent><preventing><response><soma><substance abuse><success><synapse><synaptic circuit><synaptic circuitry><thalamic><transmission process><voltage><voltage clamp><withdrawal from alcohol>