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1.  Dihydromyricetin As A Novel Anti-Alcohol Intoxication Medication 
The Journal of Neuroscience  2012;32(1):390-401.
Alcohol use disorders (AUD) constitute the most common form of substance abuse. The development of AUD involves repeated alcohol use leading to tolerance, alcohol withdrawal syndrome (AWS), physical and psychological dependence, with loss of ability to control excessive drinking. Currently there is no effective therapeutic agent for AUD without major side-effects. Dihydromyricetin (DHM, 1 mg/kg, i.p. injection), a flavonoid component of herbal medicines, counteracted acute alcohol (EtOH) intoxication, and also withdrawal signs in rats including tolerance, increased anxiety and seizure susceptibility; DHM greatly reduced EtOH consumption in an intermittent voluntary EtOH intake paradigm in rats. GABAA receptors (GABAARs) are major targets of acute and chronic EtOH actions on the brain. At the cellular levels, DHM (1 μM) antagonized both acute EtOH-induced potentiation of GABAARs and EtOH exposure/withdrawal-induced GABAAR plasticity, including alterations in responsiveness of extra- and post-synaptic GABAARs to acute EtOH, and most importantly, increases in GABAAR α4 subunit expression in hippocampus and cultured neurons. DHM anti-alcohol effects on both behavior and CNS neurons were antagonized by flumazenil (10 mg/kg in vivo, 10 μM in vitro), the benzodiazepine (BZ) antagonist. DHM competitively inhibited BZ-site [3H]flunitrazepam binding (IC50, 4.36 μM), suggesting DHM interaction with EtOH involves the BZ-sites on GABAARs. In summary, we determined DHM anti-alcoholic effects on animal models, and determined a major molecular target and cellular mechanism of DHM for counteracting alcohol intoxication and dependence. We demonstrated pharmacological properties of DHM consistent with those expected to underlie successful medical treatment of AUD; therefore DHM is a therapeutic candidate.
PMCID: PMC3292407  PMID: 22219299
2.  Enhanced tonic GABAA inhibition in typical absence epilepsy 
Nature medicine  2009;15(12):1392-1398.
The cellular mechanisms underlying typical absence seizures, which characterize various idiopathic generalized epilepsies, are not fully understood, but impaired GABAergic inhibition remains an attractive hypothesis. In contrast, we show here that extrasynaptic GABAA receptor–dependent ‘tonic’ inhibition is increased in thalamocortical neurons from diverse genetic and pharmacological models of absence seizures. Increased tonic inhibition is due to compromised GABA uptake by the GABA transporter GAT–1 in the genetic models tested, and GAT–1 is critical in governing seizure genesis. Extrasynaptic GABAA receptors are a requirement for seizures in two of the best characterized models of absence epilepsy, and the selective activation of thalamic extrasynaptic GABAA receptors is sufficient to elicit both electrographic and behavioural correlates of seizures in normal animals. These results identify an apparently common cellular pathology in typical absence seizures that may have epileptogenic significance, and highlight novel therapeutic targets for the treatment of absence epilepsy.
PMCID: PMC2824149  PMID: 19966779
extrasynaptic; tonic current; GAT–1; thalamus; spike–and–wave discharge; GAERS; stargazer; lethargic; GHB; THIP
3.  Evaluation of Un-Medicated, Self-Paced Alcohol Withdrawal 
PLoS ONE  2011;6(7):e22994.
It is currently unclear how effective un-medicated, self-paced alcohol withdrawal is in reducing alcohol consumption in alcohol dependent clients. To address this question, the current study examined the reduction in alcohol consumption, assessed by breath alcohol and drink diary self-report, of 405 alcohol-dependent clients over a 10-day, un-medicated, self-paced alcohol reduction program that included group discussion of strategies for titrating between withdrawal and intoxication. It was found that attendance at treatment sessions was associated with a reduction in alcohol consumption, reflected in both breath alcohol and diary measures, and these two measures were significantly correlated. Overall, 35% of clients achieved a zero breath alcohol reading by their final session, although this percentage increased to 56% of clients who attended all 10 sessions. Withdrawal seizures occurred in only 0.5% of clients despite 17.2% having a history of seizures in other settings. It is concluded that the alcohol reduction protocol outlined here provides an effective and safe method for reducing alcohol consumption in severely alcohol dependent clients, and that methods for augmenting attendance, such as contingency management, should enhance the effectiveness of this treatment.
PMCID: PMC3145777  PMID: 21829573
4.  Activation of brain NOP receptors attenuates acute and protracted alcohol withdrawal symptoms in the rat 
Alcohol withdrawal, refers to a cluster of symptoms that may occur from suddenly ceasing the use of alcohol after chronic or prolonged ingestion. These symptoms make alcohol abstinence difficult and increase the risk of relapse in recovering alcoholics. In previous studies, we demonstrated that treatment with N/OFQ significantly reduces alcohol consumption and attenuates alcohol-seeking behaviour induced by environmental conditioning factors or by stress in rats. In the present study we evaluated whether activation of brain NOP receptors may also attenuate alcohol withdrawal signs in rats.
For this purpose animals were subjected to a 6 day chronic alcohol intoxication (by intragastric administration) and at 8, 10 and 12 hours following cessation of alcohol exposure they were treated intracerebroventricularly (ICV) with N/OFQ (0.0, 1.0 and 3.0 μg/rat). Somatic withdrawal signs were scored after ICV treatment. In a subsequent experiment, to evaluate N/OFQ effects on alcohol withdrawal-induced anxiety another group of rats was subjected to ethanol intoxication and after one week was tested for anxiety behavior in the elevated plus maze (EPM). In the last experiment an additional group of rats was tested for anxiety elicited by acute ethanol intoxication (hangover anxiety). For this purpose, animals received an acute dose (3.0 g/kg) of 20% alcohol and 12-h later were tested in the EPM following ICV N/OFQ (0.0, 1.0 and 2.0μg/rat).
Results showed that N/OFQ significantly reduced the expression of somatic withdrawal signs and reversed anxiety-like behaviors associated with both chronic and acute alcohol intoxication. N/OFQ did not affect anxiety scores in nondependent animals.
The present findings suggest that the N/OFQ-NOP receptor system may represent a promising target for the development of new treatments to ameliorate alcohol withdrawal symptoms.
PMCID: PMC3066303  PMID: 21223310
Nociceptin; Orphanin FQ; Alcoholism; Withdrawal; Anxiety
5.  Alcohol Related Changes in Regulation of NMDA Receptor Functions 
Current Neuropharmacology  2008;6(1):39-54.
Long-term alcohol exposure may lead to development of alcohol dependence in consequence of altered neurotransmitter functions. Accumulating evidence suggests that the N-methyl-D-aspartate (NMDA) type of glutamate receptors is a particularly important site of ethanol’s action. Several studies showed that ethanol potently inhibits NMDA receptors (NMDARs) and prolonged ethanol exposition leads to a compensatory “up-regulation” of NMDAR mediated functions. Therefore, alterations in NMDAR function are supposed to contribute to the development of ethanol tolerance, dependence as well as to the acute and late signs of ethanol withdrawal.
A number of publications report alterations in the expression and phosphorylation states of NMDAR subunits, in their interaction with scaffolding proteins or other receptors in consequence of chronic ethanol treatment. Our knowledge on the regulatory processes, which modulate NMDAR functions including factors altering transcription, protein expression and post-translational modifications of NMDAR subunits, as well as those influencing their interactions with different regulatory proteins or other downstream signaling elements are incessantly increasing. The aim of this review is to summarize the complex chain of events supposedly playing a role in the up-regulation of NMDAR functions in consequence of chronic ethanol exposure.
PMCID: PMC2645546  PMID: 19305787
Alcohol dependence; NMDA receptor; subunit expression; post-translation modifications; phosphorylation/ dephosphorylation; compartmentalization.
6.  Regional neural activity within the substantia nigra during peri-ictal flurothyl generalized seizure stages 
Neurobiology of disease  2005;20(3):752-759.
Structures responsible for the onset, propagation, and cessation of generalized seizures are not known. Lesion and microinfusion studies suggest that the substantia nigra pars reticulata (SNR) seizure-controlling network could play a key role. However, the expression of neural activity within the SNR and its targets during discrete pre- and postictal periods has not been investigated. In rats, we used flurothyl to induce generalized seizures over a controlled time period and 2-deoxyglucose autoradiography mapping technique. Changes in neural activity within the SNR were region-specific. The SNRposterior was selectively active during the pre-clonic period and may represent an early gateway to seizure propagation. The SNRanterior and superior colliculus changed their activity during progression to tonic-clonic seizure, suggesting the involvement in coordinated regional activity that results in inhibitory effects on seizures. The postictal suppression state was correlated with changes in the SNR projection targets, specifically the pedunculopontine tegmental nucleus and superior colliculus.
PMCID: PMC1578684  PMID: 15950481
Autoradiography; Basal ganglia; Deoxyglucose; Flurothyl-induced primary generalized seizures; Seizure stages; Substantia nigra
7.  Molecular Pathology of Genetic Epilepsies Associated with GABAA Receptor Subunit Mutations 
Epilepsy Currents  2009;9(1):18-23.
Mutations in ligand-gated ion channel genes associated with idiopathic generalized epilepsies have been reported in excitatory acetylcholine receptor α4 and β2 subunit genes linked to autosomal dominant nocturnal frontal lobe epilepsy and in inhibitory GABAA receptor α1, β3, γ2, and δ subunit genes associated with childhood absence epilepsy, juvenile myoclonic epilepsy, pure febrile seizures, generalized epilepsy with febrile seizures plus, and generalized epilepsy with tonic–clonic seizures. Recent studies suggest that these mutations alter receptor function or biogenesis, including impaired receptor subunit messenger RNA stability, receptor subunit protein folding and stability, receptor assembly, and receptor trafficking.
PMCID: PMC2668111  PMID: 19396344
8.  Focal BOLD-fMRI changes in bicuculline-induced tonic-clonic seizures in the rat 
NeuroImage  2010;50(3):902-909.
Generalized tonic-clonic seizures cause widespread physiological changes throughout the cerebral cortex and subcortical structures in the brain. Using combined blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI) at 9.4 T and electroencephalography (EEG) these changes can be characterized with high spatiotemporal resolution. We studied BOLD changes in anesthetized Wistar rats during bicuculline-induced tonic-clonic seizures. Bicuculline, a GABAA receptor antagonist, was injected systemically and seizure activity was observed on EEG as high amplitude, high-frequency polyspike discharges followed by clonic paroxysmal activity of lower frequency, with mean electrographic seizure duration of 349 s. Our aim was to characterize the spatial localization, direction, and timing of BOLD signal changes during the pre-ictal, ictal and post-ictal periods. Group analysis was performed across seizures using paired t-maps of BOLD signal superimposed on high resolution anatomical images. Regional analysis was then performed using volumes of interest to quantify BOLD timecourses. In the pre-ictal period we found focal BOLD increases in specific areas of somatosensory cortex (S1, S2) and thalamus several seconds before seizure onset. During seizures we observed BOLD increases in cortex, brainstem and thalamus and BOLD decreases in the hippocampus. The largest ictal BOLD increases remained in the focal regions of somatosensory cortex showing pre-ictal increases. During the post-ictal period we observed widespread BOLD decreases. These findings support a model in which “generalized” tonic-clonic seizures begin with focal changes before electrographic seizure onset, which progress to non-uniform changes during seizures, possibly shedding light on the etiology and pathophysiology of similar seizures in humans.
PMCID: PMC2830359  PMID: 20079442
tonic-clonic seizure; fMRI; cortex; thalamus; bicuculline; cortical focus theory
9.  Neuroimaging Insights into the Role of Cortical GABA Systems and the Influence of Nicotine on the Recovery from Alcohol Dependence 
Neuropharmacology  2011;60(7-8):1318-1325.
This paper reviews evidence suggesting that nicotine and tobacco smoke profoundly modulate the effects of alcohol on γ-aminobutyric acid (GABA) neuronal function, specifically at the GABAA-benzodiazepine receptor (GABAA-BZR). The focus of this paper is on recent neuroimaging evidence in preclinical models as well as clinical experiments. First, we review findings implicating the role of alcohol at the GABAA-BZR and discuss the changes in GABAA-BZR availability during acute and prolonged alcohol withdrawal. Second, we discuss preclinical evidence that suggests nicotine affects GABA neuronal function indirectly by a primary action at neuronal nicotinic acetylcholine receptors. Third, we show how this evidence converges in studies that examine GABA levels and GABAA-BZRs in alcohol-dependent smokers and nonsmokers, suggesting that tobacco smoking attenuates the chemical changes that occur during alcohol withdrawal. Based on a comprehensive review of literature, we hypothesize that tobacco smoking minimizes the changes in GABA levels that typically occur during the acute cycles of drinking in alcohol-dependent individuals. Thus, during alcohol withdrawal, the continued tobacco smoking decreases the severity of the withdrawal-related changes in GABA chemistry.
PMCID: PMC3078950  PMID: 21276806
GABA; alcohol dependence; tobacco smoking; brain imaging
10.  Generalized epilepsy with febrile seizure plus (GEFS+) spectrum: Novel de novo mutation of SCN1A detected in a Malaysian patient 
In this report, we describe a 15-year-old Malaysian male patient with a de novo SCN1A mutation who experienced prolonged febrile seizures after his first seizure at 6 months of age. This boy had generalized tonic clonic seizure (GTCS) which occurred with and without fever. Sequencing analysis of voltage-gated sodium channel a1-subunit gene, SCN1A, confirmed a homozygous A to G change at nucleotide 5197 (c.5197A > G) in exon 26 resulting in amino acid substitution of asparagines to aspartate at codon 1733 of sodium channel. The mutation identified in this patient is located in the pore-forming loop of SCN1A and this case report suggests missense mutation in pore-forming loop causes generalized epilepsy with febrile seizure plus (GEFS+) with clinically more severe neurologic phenotype including intellectual disabilities (mental retardation and autism features) and neuropsychiatric disease (anxiety disorder).
PMCID: PMC3519070  PMID: 23248692
Anxiety disorder; GEFS+; GTCS; mental retardation; SCN1A
11.  Role of Altered Structure and Function of NMDA Receptors in Development of Alcohol Dependence 
Current Neuropharmacology  2005;3(4):281-297.
Long-term alcohol exposure gives rise to development of physical dependence on alcohol in consequence of changes in certain neurotransmitter functions. Accumulating evidence suggests that the glutamatergic neurotransmitter system, especially the N-methyl-D-aspartate (NMDA) type of glutamate receptors is a particularly important site of ethanol’s action, since ethanol is a potent inhibitor of the NMDA receptors (NMDARs) and prolonged ethanol exposition leads to a compensatory “upregulation” of NMDAR mediated functions supposedly contributing to the occurrence of ethanol tolerance, dependence as well as the acute and delayed signs of ethanol withdrawal.
Recently, expression of different types of NMDAR subunits was found altered after long-term ethanol exposure. Especially, the expression of the NR2B and certain splice variant forms of the NR1 subunits were increased in primary neuronal cultures treated intermittently with ethanol. Since NMDA ion channels with such an altered subunit composition have increased permeability for calcium ions, increased agonist sensitivity, and relatively slow closing kinetics, the abovementioned alterations may underlie the enhanced NMDAR activation observed after long-term ethanol exposure. In accordance with these changes, the inhibitory potential of NR2B subunit-selective NMDAR antagonists is also increased, demonstrating excellent potency against alcohol withdrawal-induced in vitro cytotoxicity. Although in vivo data are few with these compounds, according to the effectiveness of the classic NMDAR antagonists in attenuation, not only the physical symptoms, but also some affective and motivational components of alcohol withdrawal, novel NR2B subunit selective NMDAR antagonists may offer a preferable alternative in the pharmacotherapy of alcohol dependence.
PMCID: PMC2268999  PMID: 18369402
Alcohol; dependence; withdrawal; NMDA receptor; NR2B subunit selective antagonist; pharmacotherapy
12.  Importance of genetic background for risk of relapse shown in altered prefrontal cortex gene expression during abstinence following chronic alcohol intoxication 
Neuroscience  2010;173:57-75.
Alcoholism is a relapsing disorder associated with excessive consumption after periods of abstinence. Neuroadaptations in brain structure, plasticity and gene expression occur with chronic intoxication but are poorly characterized. Here we report identification of pathways altered during abstinence in prefrontal cortex, a brain region associated with cognitive dysfunction and damage in alcoholics. To determine the influence of genetic differences, an animal model was employed with widely divergent responses to alcohol withdrawal, the Withdrawal Seizure-Resistant (WSR) and Withdrawal Seizure-Prone (WSP) lines. Mice were chronically exposed to highly intoxicating concentrations of ethanol and withdrawn, then left abstinent for 21 days. Transcriptional profiling by microarray analyses identified a total of 562 genes as significantly altered during abstinence. Hierarchical cluster analysis revealed that the transcriptional response correlated with genotype/withdrawal phenotype rather than sex. Gene Ontology category overrepresentation analysis identified thyroid hormone metabolism, glutathione metabolism, axon guidance and DNA damage response as targeted classes of genes in low response WSR mice, with acetylation and histone deacetylase complex as highly dimorphic between WSR and WSP mice. Confirmation studies in WSR mice revealed both increased neurotoxicity by histopathologic examination and elevated T3 levels. Most importantly, relapse drinking was reduced by inhibition of thyroid hormone synthesis in dependent WSR mice compared to controls. These findings provide in vivo physiological and behavioral validation of the pathways identified. Combined, these results indicate a fundamentally distinct neuroadaptive response during abstinence in mice genetically selected for divergent withdrawal severity. Identification of pathways altered in abstinence may aid development of novel therapeutics for targeted treatment of relapse in abstinent alcoholics.
PMCID: PMC3014377  PMID: 21081154
alcoholism; chronic ethanol; abstinence; relapse; microarray; gene expression
13.  Pharmacotherapy for Alcohol Dependence: Anticraving Medications for Relapse Prevention 
Yonsei Medical Journal  2006;47(2):167-178.
Alcohol dependence is a chronic disorder that results from a variety of genetic, psychosocial, and environmental factors. Relapse prevention for alcohol dependence has traditionally involved psychosocial and psychotherapeutic interventions. Pharmacotherapy, however, in conjunction with behavioral therapy, is generating interest as another modality to prevent relapse and enhance abstinence. Naltrexone and acamprosate are at the forefront of the currently available pharmacological options. Naltrexone is an opioid receptor antagonist and is thought to reduce the rewarding effect of alcohol. Acamprosate normalizes the dysregulation of N-methyl-D-aspartate (NMDA)-mediated glutamatergic excitation that occurs in alcohol withdrawal and early abstinence. These different mechanisms of action and different target neurotransmitter systems may endow the two drugs with efficacy for different aspects of alcohol use behavior. Since not all patients seem to benefit from naltrexone and acamprosate, there are ongoing efforts to improve the treatment outcomes by examining the advantages of combined pharmacotherapy and exploring the variables that might predict the response of the medications. In addition, novel medications are being investigated to assess their efficacy in preventing relapse and increasing abstinence.
PMCID: PMC2687624  PMID: 16642544
Alcohol dependence; pharmacotherapy; naltrexone; acamprosate
14.  Alcohol-induced motor impairment caused by increased extrasynaptic GABAA receptor activity 
Nature neuroscience  2005;8(3):339-345.
Neuronal mechanisms underlying alcohol intoxication are unclear. We find that alcohol impairs motor coordination by enhancing tonic inhibition mediated by a specific subtype of extrasynaptic GABAA receptor (GABAR), α6β3δ, expressed exclusively in cerebellar granule cells. In recombinant studies, we characterize a naturally occurring single-nucleotide polymorphism that causes a single amino acid change (R100Q) in α6 (encoded in rats by the Gabra6 gene). We show that this change selectively increases alcohol sensitivity of α6β3δ GABARs. Behavioral and electrophysiological comparisons of Gabra6100R/100R and Gabra6100Q/100Q rats strongly suggest that alcohol impairs motor coordination by enhancing granule cell tonic inhibition. These findings identify extrasynaptic GABARs as critical targets underlying low-dose alcohol intoxication and demonstrate that subtle changes in tonic inhibition in one class of neurons can alter behavior.
PMCID: PMC2854077  PMID: 15696164
15.  Neurosteroid Replacement Therapy for Catamenial Epilepsy 
Perimenstural catamenial epilepsy, the cyclical occurrence of seizure exacerbations near the time of menstruation, affects a high proportion of women of reproductive age with drug refractory epilepsy. Enhanced seizure susceptibility in perimenstrual catamenial epilepsy is believed to be due to the withdrawal of the progesterone-derived GABAA receptor modulating neurosteroid allopregnanolone as a result of the fall in progesterone at the time of menstruation. Studies in a rat pseudopregnancy model of catamenial epilepsy indicate that following neurosteroid withdrawal there is enhanced susceptibility to chemoconvulsant seizures. There is also a transitory increase in the frequency of spontaneous seizures in epleptic rats that had experienced pilocarpine-induced status epilepticus. In the catamenial epilepsy model, there is a marked reduction in the antiseizure potency of anticonvulsant drugs, including benzodiazepines and valproate, but an increase in the anticonvulsant potency and protective index of neurosteroids such as allopregnanolone and the neurosteroid analog ganaxolone. The enhanced seizure susceptibility and benzodiazepine-resistance following neurosteroid withdrawal may be related to reduced expression and altered kinetics of synaptic GABAA receptors and increased expression of GABAA receptor subunits (such as α4) that confer benzodiazepine insensitivity. The enhanced potency of neurosteroids may be due to a relative increase following neurosteroid withdrawal in the expression of neurosteroid-sensitive δ-subunit-containing perisynaptic/extrasynaptic GABAA receptors. Positive allosteric modulatory neurosteroids and synthetic analogs such as ganaxolone may be administered to prevent catamenial seizure exacerbations, which we refer to as “neurosteroid replacement therapy.”
PMCID: PMC2682439  PMID: 19332335
catamenial epilepsy; progesterone; neurosteroid; allopregnanolone; ganaxolone; GABAA receptor
16.  Chronic Ethanol and Withdrawal Differentially Modulate Pre- and Post-synaptic Function at Glutamatergic Synapses in Rat Basolateral Amygdala 
Journal of neurophysiology  2007;98(6):3185-3196.
Withdrawal anxiety is a significant factor contributing to continued alcohol abuse in alcoholics. This anxiety is long lasting, can manifest well after the overt physical symptoms of withdrawal, and is frequently associated with relapse in recovering alcoholics. The neurobiological mechanisms governing these withdrawal-associated increases in anxiety are currently unknown. The basolateral amygdala is a major emotional center in the brain and regulates the expression of both learned-fear and anxiety. Neurotransmitter system alterations within this brain region may therefore contribute to withdrawal-associated anxiety. Since evidence suggests that glutamate-gated neurotransmitter receptors are sensitive to acute ethanol exposure, we examined the effect of chronic intermittent ethanol (CIE) and withdrawal (WD) on glutamatergic synaptic transmission in the basolateral amygdala. We found that slices prepared from CIE and WD animals had significantly increased contributions by synaptic NMDA-receptors. In addition, CIE increased the amplitude of AMPA receptor-mediated spontaneous excitatory postsynaptic currents (sEPSC), while only WD altered the amplitude and kinetics of tetrodotoxin-resistant spontaneous events (mEPSC). Similarly, the frequency of sEPSCs was increased in both CIE and WD neurons; but, only WD increased the frequency of mEPSCs. These data suggest that CIE and WD differentially alter both pre- and post-synaptic properties of BLA glutamatergic synapses. Finally, we show that microinjection of the AMPA receptor antagonist, DNQX, can attenuate withdrawal-related anxiety-like behavior. Together, our results suggest that increased glutamatergic function may contribute to anxiety expressed during withdrawal from chronic ethanol.
PMCID: PMC2269699  PMID: 17898152
17.  Protein expression of small conductance calcium-activated potassium channels is altered in inferior colliculus neurons of the genetically epilepsy-prone rat 
Brain research  2009;1270:107-111.
The genetically epilepsy-prone rat (GEPR) exhibits inherited predisposition to sound stimuli-induced generalized tonic-clonic seizures (audiogenic reflex seizures) and is a valid model to study the physiopathology of epilepsy. In this model, the inferior colliculus (IC) exhibits enhanced neuronal firing that is critical in the initiation of reflex audiogenic seizures. The mechanisms underlying IC neuronal hyperexcitability that leads to seizure susceptibility are not as yet fully understood. The present report shows that the levels of protein expression of SK1 and SK3 subtypes of the small conductance Ca2+-activated K+ channels were significantly decreased, while SK2 channel proteins were increased in IC neurons of seizure-naive GEPR-3s (SN-GEPR-3), as compared to control Sprague-Dawley rats. No significant change was found in the expression of BK channel proteins in IC neurons of SN-GEPR-3s. Single episode of reflex audiogenic seizures in the GEPR-3s did not significantly alter the protein expression of SK1-3 and BK channels in IC neurons compared to SN-GEPR-3s. Thus, downregulation of SK1 and SK3 channels and upregulation of SK2 channels provide direct evidence that these Ca2+-activated K+ channels play important roles in IC neuronal hyperexcitability that leads to inherited seizure susceptibility in the GEPR.
PMCID: PMC2697038  PMID: 19254702
Seizure susceptibility; Calcium-activated potassium channel; Protein; Inferior colliculus
18.  Targeting BK (big potassium) Channels in Epilepsy 
Expert opinion on therapeutic targets  2011;15(11):1283-1295.
Epilepsies are disorders of neuronal excitability characterized by spontaneous and recurrent seizures. Ion channels are critical for regulating neuronal excitability and, therefore, can contribute significantly to epilepsy pathophysiology. In particular, large conductance, Ca2+-activated K+ (BKCa) channels play an important role in seizure etiology. These channels are activated by both membrane depolarization and increased intracellular Ca2+. This unique coupling of Ca2+ signaling to membrane depolarization is important in controlling neuronal hyperexcitability, as outward K+ current through BKCa channels hyperpolarizes neurons.
Areas covered
This review focuses on BKCa channel structure-function and discusses the role of these channels in epilepsy pathophysiology.
Expert opinion
Loss-of-function BKCa channels contribute neuronal hyperexcitability that can lead to temporal lobe epilepsy, tonic-clonic seizures and alcohol withdrawal seizures. Similarly, BKCa channel blockade can trigger seizures and status epilepticus. Paradoxically, some mutations in BKCa channel subunit can give rise to the channel gain-of-function that leads to development of idiopathic epilepsy (primarily absence epilepsy). Seizures themselves also enhance BKCa channel currents associated with neuronal hyperexcitability, and blocking BKCa channels suppresses generalized tonic-clonic seizures. Thus, both loss-of-function and gain-of-function BKCa channels might serve as molecular targets for drugs to suppress certain seizure phenotypes including temporal lobe seizures and absence seizures, respectively.
PMCID: PMC3219529  PMID: 21923633
Anticonvulsant; Epileptogenesis; Gain-of-function; Gene mutation; Loss-of-function; Seizures
19.  Seizure induction by alcohol in patients with epilepsy experience in two hospital clinics. 
We surveyed 70 epileptic patients attending a general neurology clinic and 64 patients attending an epilepsy clinic to determine the incidence of alcohol-related seizures. Seven (10%) of the neurology clinic patients and 9 (15%) of the epilepsy clinic patients reported exacerbation of their seizures with alcohol. In the first group, two had been heavy drinkers when under-age, two had features of alcohol dependence, and three had experienced resolution of seizures following cessation of their drinking. In the second group, five drank 4 units/day or more, and one drank more heavily. The importance of alcohol in the causation of these patients' seizures had not previously been appreciated. The relationship of alcoholism to epilepsy has been recognized for many years, but the role of alcohol in the exacerbation of primary epilepsy, and in triggering seizures in epileptic patients is often not recognized. Control of alcohol ingestion is an important factor in the management of epilepsy.
PMCID: PMC1292453  PMID: 2106032
20.  Profile of lacosamide and its role in the long-term treatment of epilepsy: a perspective from the updated NICE guideline 
The goal of antiepileptic treatment is to achieve seizure freedom or seizure control. The aim of this paper is to review the evidence for the use of lacosamide for adjunctive treatment of refractory focal seizures with or without secondary generalization, within the scope of the 2012 update of the Clinical Guideline published by the National Institute for Health and Clinical Excellence (NICE).
Clinical evidence for the use of lacosamide and other antiepileptic drugs (AEDs) was systematically reviewed, evaluated, and presented to the Guideline Development Group. Only randomized clinical trials were included. Outcomes of clinical efficacy (seizure freedom, 50% reduction in seizure frequency, time to first seizure, time to 12-month remission, treatment withdrawal, and time to treatment withdrawal), experience of adverse events, and cognitive and quality of life outcomes were reviewed. A decision model was built to weigh the clinical benefits of each adjunctive AED, measured by seizure control and seizure reduction, compared with the harm from adverse events, as measured by withdrawals from treatment due to adverse events.
Lacosamide was included as part of the recommended AEDS to be used in tertiary epilepsy centers. The evidence review showed that more participants who received lacosamide as an adjunctive treatment had at least a 50% reduction in seizure frequency compared with those taking placebo. However, more participants on lacosamide were found to experience adverse events and withdrawal from treatment compared with those on placebo. The cost-effectiveness analysis showed that compared with placebo, the benefits gained from adjunctive lacosamide were modest and uncertain, whereas the costs were significantly high. Compared with other AEDs licensed for adjunctive therapy in focal seizures, lacosamide was associated with fewer quality-adjusted life years and higher costs. Therefore, the Guideline Development Group noted that the balance of benefit and harm needs to be carefully monitored in all patients.
PMCID: PMC3626368  PMID: 23630422
focal seizures; anti-epileptic drug; adjunctive therapy; clinical guideline
Alcohol (Fayetteville, N.Y.)  2009;43(1):25-33.
Withdrawal anxiety is a significant factor contributing to continued alcohol abuse in alcoholics. This anxiety is extensive, long-lasting, and develops well after the obvious physical symptoms of acute withdrawal. The neurobiological mechanisms underlying this prolonged withdrawal-induced anxiety are not well understood. The basolateral amygdala is a major emotional center in the brain and regulates the expression of anxiety. New evidence suggests that increased glutamatergic function in the basolateral amygdala may contribute to withdrawal-related anxiety following chronic ethanol exposure. Recent evidence also suggests that kainate-type ionotropic glutamate receptors are inhibited by intoxicating concentrations of acute ethanol. This acute sensitivity suggests potential contributions by these receptors to the increased glutamatergic function seen during chronic exposure. Therefore we examined the effect of chronic intermittent ethanol (CIE) and withdrawal (WD) on kainate receptor (KAR) mediated synaptic transmission in the basolateral amygdala (BLA) of Sprague Dawley rats. Our study showed that CIE, but not withdrawal, increased synaptic responses mediated by KARs. Interestingly, both CIE and WD occluded KAR-mediated synaptic plasticity. Finally, we found that BLA fEPSP responses were increased during CIE and WD via a mechanism that is independent from glutamate release from presynaptic terminals. Taken together, these data suggest that KARs might also contribute to postsynaptic increases in glutamatergic synaptic transmission during CIE and that the mechanisms responsible for the expression of KAR-dependent synaptic plasticity might be engaged by chronic ethanol exposure and withdrawal.
PMCID: PMC2662731  PMID: 19185207
basolateral amygdala; electrophysiology; kainite; anxiety; withdrawal
22.  Efficacy and safety of levetiracetam in pediatric epilepsy 
To evaluate the efficacy and tolerability of Levetiracetam (LEV) as an adjunctive therapy in pediatric patients with different generalized epilepsies.
Chart review of 22 consecutive children age 4–19 years who were treated with LEV for at least 1 year was observed retrospectively. The mean dose rang of LEV was from 250 to 2000 mg. Data were collected on epilepsy type, seizure frequency, concomitant antiepileptic drug and adverse effect.
Of the 22 patient reviewed, 13 (59%) were boys and 9 (41%) were girls. Predominant seizure types were generalized tonic–clonic seizures 13 (59%) and tonic seizure 6 (27%). Other seizure types included myoclonic seizures 2 (9%) and focal seizure 3 (5%). The results showed 10 (45%) had become free of seizure for almost 7 months to 1 year. Eight of these 10 patients (80%) had normalized EEG. Seizure frequency was reduced in 9 (41%) patients and 3 (14%) patients still had seizure. No side effects were reported related to LEV treated patients except for 1 patient.
Our results confirm that LEV may be an effective adjunctive therapy in treatment of childhood epilepsy, especially tonic–clonic seizure, with possible no evident side effect.
PMCID: PMC3744971  PMID: 23960780
Epilepsy; Seizure; Pediatric; Levetiracetam
23.  Disruption of the blood–brain barrier after generalized tonic-clonic seizures correlates with cerebrospinal fluid MMP-9 levels 
Increasing evidence suggests seizures cause blood–brain barrier (BBB) dysfunction including decreased seizure threshold and higher onset potential of future seizures. However, the mechanisms underlying BBB damage in seizures remains poorly understood. Evidence in human and animal models shows BBB disruption is associated with activation of matrix metalloproteinase-9 (MMP-9) after cerebral ischemia and inflammation. The objective of this study was to determine whether MMP-9 concentrations in cerebral spinal fluid (CSF) are associated with BBB disruption in patients after epileptic seizures.
Thirty-one patients with generalized tonic-clonic (GTC) seizures were included in the study: 20 had recurrent GTC seizures (RS), and 11 had a single GTC seizure (SS) episode. Twenty-five adult non-seizure patients were used as controls. CSF samples were collected by lumbar puncture within 24 h after seizure cessation (range: 3–15 h, mean 6.2 h). CSF MMP-9 levels were determined by an enzyme-linked immunosorbent assay (ELISA). MMP enzyme activity was measured by gelatin zymography. The CSF/serum albumin ratio (albumin quotient, QAlb) was used as a measure of blood–brain barrier permeability.
We found significantly higher CSF MMP-9 concentrations in seizure patients compared with controls (P < 0.001). CSF MMP-9 levels and QAlb values were higher in RS patients compared with SS and controls. Moreover, CSF MMP-9 concentration showed strong correlation between QAlb values (r = 0.76, P < 0.0001) and between CSF leukocyte counts (r = 0.77, P < 0.0001) in patients after seizures. Gelatin zymography showed MMP-9 proteolytic activity only in GTC seizure patients.
Our results suggest MMP-9 plays a role in BBB dysfunction, characterized by invasion of leukocytes into the CSF during seizures.
PMCID: PMC3706217  PMID: 23829879
Cerebrospinal fluid; Seizure; BBB; Metalloproteinase-9; Leukocytes
24.  Reversible posterior leukoencephalopathy syndrome during sunitinib therapy for metastatic renal cell carcinoma 
Oncology Letters  2012;3(6):1293-1296.
Sunitinib is an oral receptor tyrosine kinase inhibitor with potent antiangiogenic and antitumor activity that is approved for the treatment of advanced renal cell carcinoma (RCC), malignant gastrointestinal stromal tumors and pancreatic neuroendocrine tumors. Well-known side effects of sunitinib include hypertension, fatigue, thyroid dysfunction, cardiotoxicity, gastrointestinal toxicity and skin toxicity. In this study, we report the case of a 61-year-old male with papillary metastatic RCC who responded to sunitinib but developed generalized tonic-clonic seizures during the third cycle. Magnetic resonance imaging (MRI) was compatible with reversible posterior leukoencephalopathy syndrome (RPLS). After the administration of anti-epileptic drugs and the withdrawal of sunitinib there was rapid clinical improvement. Notably, radiological characteristics of RPLS persisted during second-line therapy with the mammalian target of rapamycin (mTOR) inhibitor everolimus and only resolved when everolimus was terminated due to disease progression. Although sunitinib-induced RPLS has been reported previously, our case is the first to additionally suggest that everolimus may sustain and therefore potentially contribute to the occurrence of RPLS.
PMCID: PMC3392579  PMID: 22783436
renal cell cancer; sunitinib; reversible posterior leukoencephalopathy syndrome
25.  The Role of GABAA Receptors in the Development of Alcoholism 
Alcoholism is a common, heritable, chronic relapsing disorder. GABAA receptors undergo allosteric modulation by ethanol, anesthetics, benzodiazepines and neurosteroids and have been implicated in the acute as well as the chronic effects of ethanol including tolerance, dependence and withdrawal. Medications targeting GABAA receptors ameliorate the symptoms of acute withdrawal. Ethanol induces plasticity in GABAA receptors: tolerance is associated with generally decreased GABAA receptor activation and differentially altered subunit expression. The dopamine (DA) mesolimbic reward pathway originating in the ventral tegmental area (VTA), and interacting stress circuitry play an important role in the development of addiction. VTA GABAergic interneurons are the primary inhibitory regulators of DA neurons and a subset of VTA GABAA receptors may be implicated in the switch from heavy drinking to dependence. GABAA receptors modulate anxiety and response to stress; important elements of sustained drinking and relapse. The GABAA receptor subunit genes clustered on chromosome 4 are highly expressed in the reward pathway. Several recent studies have provided strong evidence that one of these genes, GABRA2, is implicated in alcoholism in humans. The influence of the interaction between ethanol and GABAA receptors in the reward pathway on the development of alcoholism together with genetic and epigenetic vulnerabilities will be explored in this review.
PMCID: PMC2577853  PMID: 18440057
GABA; ethanol; neurosteroids; benzodiazepines; tolerance; withdrawal; reward; VTA; stress; anxiety genes; GABRA2

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