Biochemical and neurotransmitter changes implicated in alcohol-induced brain damage in chronic or 'binge drinking' alcohol abuse

Influence of green tea on alcohol aggravated neurodegeneration of cortex, cerebellum and hippocampus of STZ-induced diabetic rats

The main aim of this study was to evaluate the cytotoxic effects of chronic alcohol consumption on various regions of diabetic brain and preventive role of GTE. Clinical, experimental and histopathological observations indicate chronic, excessive alcohol consumption aggravates the free radical-mediated oxidative and nitrosative stress in several tissues including brain. Treatment with Epigallocatechin gallate (EGCG) significantly reduced the levels of oxidative/nitrosative stress paradigms, increased glutathione (GSH) levels and enhanced the activities of antioxidant enzymes. Histopathology evaluation revealed the possible influence of EGCG in reversing alcohol exacerbated diabetes-induced damage in cortex, cerebellum and hippocampus of brain. Furthermore, these studies have provided evidence to show how EGCG can exactly occupy the position in functional sites of nNOS (neuronal nitric oxide synthase) and induce a conformational change, inhibition of enzymatic activity and prevention of neurodegeneration/necrotic changes of tissue, in comparison with the rosiglitazone and glibenclamide. To summarise, this research has offered useful information on the action of EGCG that would provide potential protection against ethanol exacerbated diabetic brain damageand additional evidence for the use of EGCG as a lead compound for drug discovery.

Neuropharmacology of Alcohol Addiction with Special Emphasis on Proteomic Approaches for Identification of Novel Therapeutic Targets

Alcohol is a generic pharmacological agent with only a few recognized primary targets. Nmethyl- D-aspartate, gamma-aminobutyric acid, glycine, 5-hydroxytryptamine 3 (serotonin), nicotinic acetylcholine receptors, and L-type Ca2+ channels and G-protein-activated inwardly rectifying K channels are all involved. Following the first hit of alcohol on specific brain targets, the second wave of indirect effects on various neurotransmitter/neuropeptide systems begins, leading to the typical acute behavioral effects of alcohol, which range from disinhibition to sedation and even hypnosis as alcohol concentrations rise. Recent research has revealed that gene regulation is significantly more complex than previously thought and does not fully explain changes in protein levels. As a result, studying the proteome directly, which differs from the genome/transcriptome in terms of complexity and dynamicity, has provided unique insights into extraordinary advances in proteomic techniques that have changed the way we can analyze the composition, regulation, and function of protein complexes and pathways underlying altered neurobiological conditions. Neuroproteomics has the potential to revolutionize alcohol research by allowing researchers to gain a better knowledge of how alcohol impacts protein structure, function, connections, and networks on a global scale. The amount of information collected from these breakthroughs can aid in identifying valuable biomarkers for early detection and improved prognosis of an alcohol use disorder and future pharmaceutical targets for the treatment of alcoholism.

Acute Administration of Ethanol and of a D1-Receptor Antagonist Affects the Behavior and Neurochemistry of Adult Zebrafish

Alcohol abuse represents major societal problems, an unmet medical need resulting from our incomplete understanding of the mechanisms underlying alcohol’s actions in the brain. To uncover these mechanisms, animal models have been proposed. Here, we explore the effects of acute alcohol administration in zebrafish, a promising animal model in alcohol research. One mechanism via which alcohol may influence behavior is the dopaminergic neurotransmitter system. As a proof-of-concept analysis, we study how D1 dopamine-receptor antagonism may alter the effects of acute alcohol on the behavior of adult zebrafish and on whole brain levels of neurochemicals. We conduct these analyses using a quasi-inbred strain, AB, and a genetically heterogeneous population SFWT. Our results uncover significant alcohol x D1-R antagonist interaction and main effects of these factors in shoaling, but only additive effects of these factors in measures of exploratory behavior. We also find interacting and main effects of alcohol and the D1-R antagonist on dopamine and DOPAC levels, but only alcohol effects on serotonin. We also uncover several strain dependent effects. These results demonstrate that acute alcohol may act through dopaminergic mechanisms for some but not all behavioral phenotypes, a novel discovery, and also suggest that strain differences may, in the future, help us identify molecular mechanisms underlying acute alcohol effects.

The neurobiological markers of acute alcohol's subjective effects in humans

The ingestion of alcohol yields acute biphasic subjective effects: stimulation before sedation. Despite their predictive relevance to the development of alcohol use disorders (AUD), the neurobiological markers accounting for the biphasic effects of alcohol remain poorly understood in humans. Informed by converging lines of evidence, this study tested the hypothesis that alcohol ingestion acutely increases gamma-aminobutyric acid (GABA)-mediated inhibition, which would positively and negatively predict the feeling of stimulation and sedation, respectively. To do so, healthy participants (n = 20) ingested a single dose of 94% ABV alcohol (males: 1.0 ml/kg; females: 0.85 ml/kg) in a randomized placebo-controlled cross-over design. The alcohol's biphasic effects were assessed with the Brief-Biphasic Alcohol Effects Scale, and non-invasive neurobiological markers were measured with transcranial magnetic stimulation, before and every 30 min (up to 120 min) after the complete ingestion of the beverage. Results showed that acute alcohol ingestion selectively increased the duration of the cortical silent period (CSP) as compared to placebo, suggesting that alcohol increases non-specific GABAergic inhibition. Importantly, CSP duration positively and negatively predicted increases in the feeling of stimulation and sedation, respectively, suggesting that stimulation emerges as GABAergic inhibition increases and that sedation emerges as GABAergic inhibition returns to baseline values. Overall, these results suggest that modulations of GABAergic inhibition are central to the acute biphasic subjective effects of alcohol, providing a potential preventive target to curb the progression of at-risk individuals to AUD.

New Paradigms of Old Psychedelics in Schizophrenia

Psychedelics such as lysergic acid diethylamide (LSD), psilocybin (magic mushrooms), and mescaline exhibit intense effects on the human brain and behaviour. In recent years, there has been a surge in studies investigating these drugs because clinical studies have shown that these once banned drugs are well tolerated and efficacious in medically supervised low doses called microdosing. Psychedelics have demonstrated efficacy in treating neuropsychiatric maladies such as difficult to treat anxiety, depression, mood disorders, obsessive compulsive disorders, suicidal ideation, posttraumatic stress disorder, and also in treating substance use disorders. The primary mode of action of psychedelics is activation of serotonin 5-HT_2A receptors affecting cognition and brain connectivity through the modulation of several downstream signalling pathways via complex molecular mechanisms. Some atypical antipsychotic drugs (APDs) primarily exhibit pharmacological actions through 5-HT_2A receptors, which are also the target of psychedelic drugs. Psychedelic drugs including the newer second generation along with the glutamatergic APDs are thought to mediate pharmacological actions through a common pathway, i.e., a complex serotonin-glutamate receptor interaction in cortical neurons of pyramidal origin. Furthermore, psychedelic drugs have been reported to act via a complex interplay between 5HT_2A, mGlu2/3, and NMDA receptors to mediate neurobehavioral and pharmacological actions. Findings from recent studies have suggested that serotoninergic and glutamatergic neurotransmissions are very closely connected in producing pharmacological responses to psychedelics and antipsychotic medication. Emerging hypotheses suggest that psychedelics work through brain resetting mechanisms. Hence, there is a need to dig deeply into psychedelic neurobiology to uncover how psychedelics could best be used as scientific tools to benefit psychiatric disorders including schizophrenia.

Limited evidence for a moderating effect of HIV status on brain age in heavy episodic drinkers

We set out to test the hypothesis that greater brain ageing will be observed in people with HIV (PWH) and those who engage in heavy episodic drinking (HED), with their combined effects being especially detrimental in cognitive control brain networks. We correlated measures of "brain age gap" (BAG) and neurocognitive impairment in participants with and without HIV and HED. Sixty-nine participants were recruited from a community health centre in Cape Town: HIV - /HED - (N = 17), HIV + /HED - (N = 14), HIV - /HED + (N = 21), and HIV + /HED + (N = 17). Brain age was modelled using structural MRI features from the whole brain or one of six brain regions. Linear regression models were employed to identify differences in BAG between patient groups and controls. Associations between BAG and clinical data were tested using bivariate statistical methods. Compared to controls, greater global BAG was observed in heavy drinkers, both with (Cohen's d = 1.52) and without (d = 1.61) HIV. Differences in BAG between HED participants and controls were observed for the cingulate and parietal cortex, as well as subcortically. A larger BAG was associated with higher total drinking scores but not nadir CD4 count or current HIV viral load. The association between heavy episodic drinking and BAG, independent of HIV status, points to the importance of screening for alcohol use disorders in primary care. The relatively large contribution of cognitive control brain regions to BAG highlights the utility of assessing the contribution of different brain regions to brain age.

Alcohol and the Brain

Alcohol works on the brain to produce its desired effects, e.g., sociability and intoxication, and hence the brain is an important organ for exploring subsequent harms. These come in many different forms such as the consequences of damage during intoxication, e.g., from falls and fights, damage from withdrawal, damage from the toxicity of alcohol and its metabolites and altered brain structure and function with implications for behavioral processes such as craving and addiction. On top of that are peripheral factors that compound brain damage such as poor diet, vitamin deficiencies leading to Wernicke-Korsakoff syndrome. Prenatal alcohol exposure can also have a profound impact on brain development and lead to irremediable changes of fetal alcohol syndrome. This chapter briefly reviews aspects of these with a particular focus on recent brain imaging results. Cardiovascular effects of alcohol that lead to brain pathology are not covered as they are dealt with elsewhere in the volume.

Changes in Brain Dopamine Extracellular Concentration after Ethanol Administration; Rat Microdialysis Studies

AIMS

The purpose of this review is to evaluate microdialysis studies where alterations in the dopaminergic system have been evaluated after different intoxication states, in animals showing preference or not for alcohol, as well as during alcohol withdrawal.

METHODS

Ethanol administration induces varying alterations in dopamine microdialysate concentrations, thereby modulating the functional output of the dopaminergic system.

RESULTS

Administration of low doses of ethanol, intraperitoneally, intravenously, orally or directly into the nucleus accumbens, NAc, increases mesolimbic dopamine, transmission, as shown by increases in dopamine content. Chronic alcohol administration to rats, which show alcohol-dependent behaviour, induced little change in basal dopamine microdialysis content. In contrast, reduced basal dopamine content occurred after ethanol withdrawal, which might be the stimulus to induce alcohol cravings and consumption. Intermittent alcohol consumption did not identify any consistent changes in dopamine transmission. Animals which have been selectively or genetically bred for alcohol preference did not show consistent changes in basal dopamine content although, exhibited a significant ethanol-evoked dopamine response by comparison to non-preference animals.

CONCLUSIONS

Microdialysis has provided valuable information about ethanol-evoked dopamine release in the different animal models of alcohol abuse. Acute ethanol administration increases dopamine transmission in the rat NAc whereas chronic ethanol consumption shows variable results which might reflect whether the rat is prior to or experiencing ethanol withdrawal. Ethanol withdrawal significantly decreases the extracellular dopamine content. Such changes in dopamine surges will contribute to both drug dependence, e.g. susceptibility to drug withdrawal, and addiction, by compromising the ability to react to normal dopamine fluctuations.

Primed for addiction: A critical review of the role of microglia in the neurodevelopmental consequences of adolescent alcohol drinking

Alcohol is one of the most widely used recreational substances worldwide, with drinking frequently initiated during adolescence. The developmental state of the adolescent brain makes it vulnerable to initiating alcohol use, often in high doses, and particularly susceptible to alcohol-induced brain changes. Microglia, the brain parenchymal macrophages, have been implicated in mediating some of these effects, though the role that these cells play in the progression from alcohol drinking to dependence remains unclear. Microglia are uniquely positioned to sense and respond to central nervous system insult, and are now understood to exhibit innate immune memory, or "priming," altering their future functional responses based on prior exposures. In alcohol use disorders (AUDs), the role of microglia is debated. Whereas microglial activation can be pathogenic, contributing to neuroinflammation, tissue damage, and behavioral changes, or protective, it can also engage protective functions, providing support and mediating the resolution of damage. Understanding the role of microglia in adolescent AUDs is complicated by the fact that microglia are thought to be involved in developmental processes such as synaptic refinement and myelination, which underlie the functional maturation of multiple brain systems in adolescence. Thus, the role microglia play in the impact of alcohol use in adolescence is likely multifaceted. Long-term sequelae may be due to a failure to recover from EtOH-induced tissue damage, altered neurodevelopmental trajectories, and/or persistent changes to microglial responsivity and function. Here, we review critically the literature surrounding the effects of alcohol on microglia in models of adolescent alcohol misuse. We attempt to disentangle what is known about microglia from other neuroimmune effectors, to which we apply recent discoveries on the role of microglia in development and plasticity. Considered altogether, these studies challenge assumptions that proinflammatory microglia drive addiction. Alcohol priming microglia and thereby perturbing their homeostatic roles in neurodevelopment, especially during critical periods of plasticity such as adolescence, may have more serious implications for the neuropathogenesis of AUDs in adolescents.

The relationship between alcohol consumption and dry eye

PURPOSE

To assess the association between dry eye disease (DED) and alcohol consumption using a large population-based cohort.

METHODS

77,145 participants (19-94 years, 59% female) from the Dutch Lifelines cohort were cross-sectionally assessed for DED using the Women's Health Study (WHS) dry eye questionnaire. Alcohol intake was assessed using self-reported food frequency questionnaires. The relationship between DED and alcohol use was analyzed using logistic regression, corrected for age, sex, BMI, smoking status, education, income, and 55 potentially confounding comorbidities.

RESULTS

Overall, 30.0% of participants had symptomatic dry eye. Alcohol use significantly increased the risk of symptomatic dry eye in females (odds ratio [OR] 1.095, 95%CI 1.045-1.148), but not in males (OR 0.988, 95%CI 0.900-1.084). Contrarily, in male drinkers, increasing alcohol intake (in 10 g/day) had a protective effect on symptomatic dry eye (OR 0.962, 95%CI 0.934-0.992), which was not seen in females (OR 0.986, 95%CI 0.950-1.023). Alcohol use and intake had a sex-specific effect on all outcomes of DED assessed: symptomatic dry eye, highly symptomatic dry eye, clinical diagnosis, and WHS definition dry eye.

CONCLUSIONS

This large population-based study found alcohol use to have a clear sex-specific effect on DED, presenting as a risk-factor only in females. This adds to the evidence of sex-specific pathophysiological mechanisms of dry eye and illustrates the importance of sex stratification in studies investigating DED. The mild protective effect of increased alcohol intake in male drinkers is advised to be interpreted with caution, as alcohol's other health effects might be of greater clinical significance.

MRI Analysis Of the Water Content Change In the Brain During Acute Ethanol Consumption Via Quantitative Water Mapping

AIMS

Alcohol consumption influences the water balance in the brain. While the impact of chronic alcohol misuse on cerebral water content has been the subject of several studies, less is known about the effects of acute alcohol misuse, with contradictory results in the literature. Therefore, we investigated the effects of acute alcohol intoxication on cerebral water content using a precise quantitative magnetic resonance imaging (MRI) sequence.

METHODS

In a prospective study, we measured cerebral water content in 20 healthy volunteers before alcohol consumption and after reaching a breath alcohol concentration of 1 ‰. A quantitative MRI water mapping sequence was conducted on a clinical 3 T system. Non-alcoholic fluid input and output were documented and accounted for. Water content was assessed for whole brain, grey and white matter and more specifically for regions known to be affected by acute or chronic alcohol misuse (occipital and frontal lobes, thalamus and pons). Changes in the volume of grey and white matter as well as the whole brain were examined.

RESULTS

Quantitative cerebral water content before and after acute alcohol consumption did not differ significantly (P ≥ 0.07), with changes often being within the range of measurement accuracy. Whole brain, white and grey matter volume did not change significantly (P ≥ 0.12).

CONCLUSION

The results of our study show no significant water content or volume change in the brain after recent alcohol intake in healthy volunteers. This accounts for the whole brain, grey and white matter, occipital and frontal lobes, thalamus and pons.

The possible role of CREB-BDNF signaling pathway in neuroprotective effects of minocycline against alcohol-induced neurodegeneration: molecular and behavioral evidences

Abuse of alcohol triggers neurodegeneration in human brain. Minocycline has characteristics conferring neuroprotection. Current study evaluates the role of the CREB-BDNF signaling pathway in mediating minocycline's neuroprotective effects against alcohol-induced neurodegeneration. Seventy adult male rats were randomly split into groups 1 and 2 that received saline and alcohol (2 g/kg/day by gavage, once daily), respectively, and groups 3, 4, 5, and 6 were treated simultaneously with alcohol and minocycline (10, 20, 30 and 40 mg/kg I.P, respectively) for 21 days. Group 7 received minocycline alone (40 mg/kg, i.p) for 21 days. Morris water maze (MWM) has been used to assess cognitive activity. Hippocampal neurodegenerative and histological parameters as well as cyclic AMP response element-binding protein (CREB) and brain-derived neurotrophic factor (BDNF) levels were assessed. Alcohol impaired cognition, and concurrent therapy with various minocycline doses attenuated alcohol-induced cognition disturbances. Additionally, alcohol administration boosted lipid peroxidation and levels of glutathione in oxidized form (GSSG), tumor necrosis factor alpha (TNF-α), interleukin 1 beta (IL-1β), and Bax protein, while decreased reducing type of glutathione (GSH), Bcl-2 protein, phosphorylated CREB, and BDNF levels in rat hippocampus. Alcohol also decreased the activity in the hippocampus of superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione reductase (GR). In comparison, minocycline attenuated alcohol-induced neurodegeneration; elevating expression levels of P-CREB and BDNF and inhibited alcohol induced histopathological changes in both dentate gyrus (DG) and CA1 of hippocampus. Thus, minocycline is likely to provide neuroprotection against alcohol-induced neurodegeneration through mediation of the P-CREB/BDNF signaling pathway.

Electroencephalographic signatures of the binge drinking pattern during adolescence and young adulthood: A PRISMA-driven systematic review

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Controls and binge drinkers (BDs) do not differ in their behavioral performance.

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BDs show increased neural activity during attention, working memory and inhibition.

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Augmented P3 amplitude in BDs was the most solid electrophysiological finding.

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Evidence does not support specific gender vulnerabilities to the effects of BD.

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Memory, emotional processing and decision-making processes need further exploration.

Research on neurophysiological impairments associated with binge drinking (BD), an excessive but episodic alcohol use pattern, has significantly increased over the last decade. This work is the first to systematically review –following PRISMA guidelines- the empirical evidence regarding the effects of BD on neural activity –assessed by electroencephalography- of adolescents and young adults. A systematic review was conducted in 34 studies (N = 1723). Results indicated that binge drinkers (BDs) showed similar behavioral performance as non/low drinkers. The most solid electrophysiological finding was an augmented P3 amplitude during attention, working memory and inhibition tasks. This increased neural activity suggests the recruitment of additional resources to perform the task at adequate/successful levels, which supports the neurocompensation hypothesis. Similar to alcoholics, BDs also displayed increased reactivity to alcohol-related cues, augmented resting-state electrophysiological signal and reduced activity during error detection –which gives support to the continuum hypothesis. Evidence does not seem to support greater vulnerability to BD in females. Replication and longitudinal studies are required to account for mixed results and to elucidate the extent/direction of the neural impairments associated with BD.

Jugend und Alkohol

Im vorliegenden Artikel wird auf die Rolle von Alkohol in unserer Gesellschaft sowie auf dessen Bedeutung für Jugendliche eingegangen. Spezifika der Wechselwirkung von Alkohol und dem adoleszenten Gehirn werden erläutert und die epidemiologische Entwicklung des Alkoholkonsums bei österreichischen Minderjährigen beschrieben. Es werden darüber hinaus relevanteRisiken für problematische Konsummuster und mögliche Wege zur Prävention erörtert.

Evolution of BDNF serum levels during the first six months after alcohol withdrawal

OBJECTIVES

Brain-Derived Neurotrophic Factor (BDNF) has been associated with alcohol dependence and appear to vary after withdrawal, although the link with the withdrawal outcome on the long term is unknown. We aimed to assess the evolution of BDNF levels during the six months following withdrawal and determine the association with the status of alcohol consumption.

METHODS

Serum BDNF levels of alcohol-dependent patients (n = 248) and biological and clinical parameters were determined at the time of alcohol cessation (D0), 14 days (D14), 28 days (D28), and 2, 4, and 6 months after (M2, M4, M6).

RESULTS

Abstinence decreased during follow-up and was 31.9% after six months. BDNF levels increased by 14 days after withdrawal and remained elevated throughout the six-month period, independently of alcohol consumption. Serum BDNF levels evolved over time (p < 0.0001), with a correlation between BDNF and GGT levels. The prescription of baclofen at the time of withdrawal was associated with higher serum BDNF levels throughout the follow-up and that of anti-inflammatory drugs with lower BDNF levels.

CONCLUSIONS

A link between BDNF levels, liver function, and the inflammatory state in the context of alcohol abuse and not only with alcohol dependence itself is proposed.

Association of Alcohol-Induced Loss of Consciousness and Overall Alcohol Consumption With Risk for Dementia

IMPORTANCE

Evidence on alcohol consumption as a risk factor for dementia usually relates to overall consumption. The role of alcohol-induced loss of consciousness is uncertain.

OBJECTIVE

To examine the risk of future dementia associated with overall alcohol consumption and alcohol-induced loss of consciousness in a population of current drinkers.

DESIGN, SETTING, AND PARTICIPANTS

Seven cohort studies from the UK, France, Sweden, and Finland (IPD-Work consortium) including 131 415 participants were examined. At baseline (1986-2012), participants were aged 18 to 77 years, reported alcohol consumption, and were free of diagnosed dementia. Dementia was examined during a mean follow-up of 14.4 years (range, 12.3-30.1). Data analysis was conducted from November 17, 2019, to May 23, 2020.

EXPOSURES

Self-reported overall consumption and loss of consciousness due to alcohol consumption were assessed at baseline. Two thresholds were used to define heavy overall consumption: greater than 14 units (U) (UK definition) and greater than 21 U (US definition) per week.

MAIN OUTCOMES AND MEASURES

Dementia and alcohol-related disorders to 2016 were ascertained from linked electronic health records.

RESULTS

Of the 131 415 participants (mean [SD] age, 43.0 [10.4] years; 80 344 [61.1%] women), 1081 individuals (0.8%) developed dementia. After adjustment for potential confounders, the hazard ratio (HR) was 1.16 (95% CI, 0.98-1.37) for consuming greater than 14 vs 1 to 14 U of alcohol per week and 1.22 (95% CI, 1.01-1.48) for greater than 21 vs 1 to 21 U/wk. Of the 96 591 participants with data on loss of consciousness, 10 004 individuals (10.4%) reported having lost consciousness due to alcohol consumption in the past 12 months. The association between loss of consciousness and dementia was observed in men (HR, 2.86; 95% CI, 1.77-4.63) and women (HR, 2.09; 95% CI, 1.34-3.25) during the first 10 years of follow-up (HR, 2.72; 95% CI, 1.78-4.15), after excluding the first 10 years of follow-up (HR, 1.86; 95% CI, 1.16-2.99), and for early-onset (<65 y: HR, 2.21; 95% CI, 1.46-3.34) and late-onset (≥65 y: HR, 2.25; 95% CI, 1.38-3.66) dementia, Alzheimer disease (HR, 1.98; 95% CI, 1.28-3.07), and dementia with features of atherosclerotic cardiovascular disease (HR, 4.18; 95% CI, 1.86-9.37). The association with dementia was not explained by 14 other alcohol-related conditions. With moderate drinkers (1-14 U/wk) who had not lost consciousness as the reference group, the HR for dementia was twice as high in participants who reported having lost consciousness, whether their mean weekly consumption was moderate (HR, 2.19; 95% CI, 1.42-3.37) or heavy (HR, 2.36; 95% CI, 1.57-3.54).

CONCLUSIONS AND RELEVANCE

The findings of this study suggest that alcohol-induced loss of consciousness, irrespective of overall alcohol consumption, is associated with a subsequent increase in the risk of dementia.

Ethanol-activated CaMKII signaling induces neuronal apoptosis through Drp1-mediated excessive mitochondrial fission and JNK1-dependent NLRP3 inflammasome activation

Background

Neurodegeneration is a representative phenotype of patients with chronic alcoholism. Ethanol-induced calcium overload causes NOD-like receptor protein 3 (NLRP3) inflammasome formation and an imbalance in mitochondrial dynamics, closely associated with the pathogenesis of neurodegeneration. However, how calcium regulates this process in neuronal cells is poorly understood. Therefore, the present study investigated the detailed mechanism of calcium-regulated mitochondrial dynamics and NLRP3 inflammasome formation in neuronal cells by ethanol.

Methods

In this study, we used the SK-N-MC human neuroblastoma cell line. To confirm the expression level of the mRNA and protein, real time quantitative PCR and western blot were performed. Co-immunoprecipitation and Immunofluorescence staining were conducted to confirm the complex formation or interaction of the proteins. Flow cytometry was used to analyze intracellular calcium, mitochondrial dysfunction and neuronal apoptosis.

Results

Ethanol increased cleaved caspase-3 levels and mitochondrial reactive oxygen species (ROS) generation associated with neuronal apoptosis. In addition, ethanol increased protein kinase A (PKA) activation and cAMP-response-element-binding protein (CREB) phosphorylation, which increased N-methyl-D-aspartate receptor (NMDAR) expression. Ethanol-increased NMDAR induced intracellular calcium overload and calmodulin-dependent protein kinase II (CaMKII) activation leading to phosphorylation of dynamin-related protein 1 (Drp1) and c-Jun N-terminal protein kinase 1 (JNK1). Drp1 phosphorylation promoted Drp1 translocation to the mitochondria, resulting in excessive mitochondrial fission, mitochondrial ROS accumulation, and loss of mitochondrial membrane potential, which was recovered by Drp1 inhibitor pretreatment. Ethanol-induced JNK1 phosphorylation activated the NLRP3 inflammasome that induced caspase-1 dependent mitophagy inhibition, thereby exacerbating ROS accumulation and causing cell death. Suppressing caspase-1 induced mitophagy and reversed the ethanol-induced apoptosis in neuronal cells.

Conclusions

Our results demonstrated that ethanol upregulated NMDAR-dependent CaMKII phosphorylation which is essential for Drp1-mediated excessive mitochondrial fission and the JNK1-induced NLRP3 inflammasome activation resulting in neuronal apoptosis.

24-Epibrassinolide protects against ethanol-induced behavioural teratogenesis in zebrafish embryo

Embryonic studies have demonstrated the neurotoxic, teratogenic, and neurobehavioral toxicity of ethanol (EtOH). Although multiple mechanisms may contribute to these effects, oxidative stress has been described as the major damage pathway. In this regard, natural antioxidants have the potential to counteract oxidative stress-induced cellular damage. Therefore, the present study aimed to investigate the potential protective role of 24-epibrassinolide (24-EPI), a natural brassinosteroid with proved antioxidant properties, in EtOH-induced teratogenic effects during early zebrafish development. Embryos (~2 h post-fertilization - hpf) were exposed to 1 % EtOH, co-exposed to 24-EPI (0.01, 0.1 and 1 μM) and to 24-EPI alone (1 μM) for 24 h. Following exposure, biochemical evaluations were made at 26 hpf, developmental analysis was made throughout the embryo-larval period, and behavioural responses were evaluated at 120 hpf. Exposure to 1 % EtOH caused an increase in the number of malformations, which were diminished by 24-EPI. In addition, EtOH induced an accumulation of GSSG and consequent reduction of GSH:GSSG ratio, indicating the involvement of oxidative mechanisms in the EtOH-induced effects. These were reverted by 24-EPI as proved by the GSSG levels and GSH:GSSG ratio that returned to control values. Furthermore, exposure to EtOH resulted in behavioural deficits at 120 hpf as observed by the disrupted response to an aversive stimulus, suggesting the involvement of neurotoxic mechanisms. 24-EPI restored the behavioural deficits observed in a dose-dependent manner. The absence of effects in the embryos exposed solely to 24-EPI showed its safety during the exposure period. In conclusion, EtOH caused developmental teratogenicity and behavioural toxicity by inducing glutathione changes, which were prevented by 24-EPI.

Biomarkers and neuromodulation techniques in substance use disorders

Addictive disorders are a severe health concern. Conventional therapies have just moderate success and the probability of relapse after treatment remains high. Brain stimulation techniques, such as transcranial Direct Current Stimulation (tDCS) and Deep Brain Stimulation (DBS), have been shown to be effective in reducing subjectively rated substance craving. However, there are few objective and measurable parameters that reflect neural mechanisms of addictive disorders and relapse. Key electrophysiological features that characterize substance related changes in neural processing are Event-Related Potentials (ERP). These high temporal resolution measurements of brain activity are able to identify neurocognitive correlates of addictive behaviours. Moreover, ERP have shown utility as biomarkers to predict treatment outcome and relapse probability. A future direction for the treatment of addiction might include neural interfaces able to detect addiction-related neurophysiological parameters and deploy neuromodulation adapted to the identified pathological features in a closed-loop fashion. Such systems may go beyond electrical recording and stimulation to employ sensing and neuromodulation in the pharmacological domain as well as advanced signal analysis and machine learning algorithms. In this review, we describe the state-of-the-art in the treatment of addictive disorders with electrical brain stimulation and its effect on addiction-related neurophysiological markers. We discuss advanced signal processing approaches and multi-modal neural interfaces as building blocks in future bioelectronics systems for treatment of addictive disorders.

Alcohol Hangover: Underlying Biochemical, Inflammatory and Neurochemical Mechanisms

AIM

To review current alcohol hangover research in animals and humans and evaluate key evidence for contributing biological factors.

METHOD

Narrative review with alcohol hangover defined as the state the day after a single episode of heavy drinking, when the alcohol concentration in the blood approaches zero.

RESULTS

Many of the human studies of hangover are not well controlled, with subjects consuming different concentrations of alcohol over variable time periods and evaluation not blinded. Also, studies have measured different symptoms and use varying methods of measurement. Animal studies show variations with respect to the route of administration (intragastric or intraperitoneal), the behavioural tests utilised and discrepancy in the timepoint used for hangover onset. Human studies have the advantage over animal models of being able to assess subjective hangover severity and its correlation with specific behaviours and/or biochemical markers. However, animal models provide valuable insight into the neural mechanisms of hangover. Despite such limitations, several hangover models have identified pathological changes which correlate with the hangover state. We review studies examining the contribution of alcohol's metabolites, neurotransmitter changes with particular reference to glutamate, neuroinflammation and ingested congeners to hangover severity.

CONCLUSION

Alcohol metabolites, neurotransmitter alterations, inflammatory factors and mitochondrial dysfunction are the most likely factors in hangover pathology. Future research should aim to investigate the relationship between these factors and their causal role.

Evaluation of the dopaminergic system with positron-emission tomography in alcohol abuse: A systematic review

OBJECTIVE

Performed a systematic review to evaluated the dopaminergic system in alcohol abuse in a systematic review in humans.

METHOD

A search of the electronic databases was proceeded, on MEDLINE, EMBASE, Cochrane Library, Insight and Gray literature (Google Scholar and the British Library) for studies published until August 2018. A search strategy was developed using the terms: "dopamine" and "ethanol" or ""alcohol"," and "positron-emission tomography" as text words and Medical Subject Headings (i.e., MeSH and EMTREE) and searched.

RESULTS

We found 293 studies. After reading titles and abstracts 235 were considered irrelevant, as they did not meet the inclusion criteria. For the reading of the full text, 50 studies were analyzed. Of these 41 were excluded with reasons by study design, patient population, intervention and outcomes. Nine studies were included in our qualitative synthesis. Four studies have resulted in a reduction in availability only at the D2 receptor in different brain regions. Concerning the D3 receptor alone only one study reported this finding and four studies reported a decrease in both receptors.

CONCLUSION

Changes in D2 receptors in several brain regions in human alcoholics were found in a systematic review.

Alcohol withdrawal is associated with poorer outcome in acute ischemic stroke

OBJECTIVE

To determine the association between alcohol abuse (AA) and alcohol withdrawal (AW) with acute ischemic stroke (AIS) outcomes.

METHODS

All adult AIS admissions in the United States from 2004 to 2014 were identified from the National Inpatient Sample (weighted n = 4,438,968). Multivariable-adjusted models were used to evaluate the association of AW with in-hospital medical complications, mortality, cost, and length of stay in patients with AIS.

RESULTS

Of the AA admissions, 10.6% of patients, representing 0.4% of all AIS, developed AW. The prevalence of AA and AW in AIS increased by 45.2% and 40.0%, respectively, over time (p for trend <0.001). Patients with AA were predominantly men (80.2%), white (65.9%), and in the 40- to 59-year (44.6%) and 60- to 79-year (45.6%) age groups. After multivariable adjustment, AIS admissions with AW had >50% increased odds of urinary tract infection, pneumonia, sepsis, gastrointestinal bleeding, deep venous thrombosis, and acute renal failure compared to those without AW. Patients with AW were also 32% more likely to die during their AIS hospitalization compared to those without AW (odds ratio 1.32, 95% confidence interval 1.11-1.58). AW was associated with ≈15-day increase in length of stay and ≈$5,000 increase in hospitalization cost (p < 0.001).

CONCLUSION

AW is associated with increased cost, longer hospitalizations, and higher odds of medical complications and in-hospital mortality after AIS. Proactive surveillance and management of AW may be important in improving outcomes in these patients.

Exercise-driven restoration of the alcohol-damaged brain

There are vast literatures on the neural effects of alcohol and the neural effects of exercise. Simply put, exercise is associated with brain health, alcohol is not, and the mechanisms by which exercise benefits the brain directly counteract the mechanisms by which alcohol damages it. Although a degree of brain recovery naturally occurs upon cessation of alcohol consumption, effective treatments for alcohol-induced brain damage are badly needed, and exercise is an excellent candidate from a mechanistic standpoint. In this chapter, we cover the small but growing literature on the interactive neural effects of alcohol and exercise, and the capacity of exercise to repair alcohol-induced brain damage. Increasingly, exercise is being used as a component of treatment for alcohol use disorders (AUD), not because it reverses alcohol-induced brain damage, but because it represents a rewarding, alcohol-free activity that could reduce alcohol cravings and improve comorbid conditions such as anxiety and depression. It is important to bear in mind, however, that multiple studies attest to a counterintuitive positive relationship between alcohol intake and exercise. We therefore conclude with cautionary notes regarding the use of exercise to repair the brain after alcohol damage.

Cholinergic system and exploratory behavior are changed after weekly-binge ethanol exposure in zebrafish

Binge drinking is characterized by excessive alcohol consumption in a short period of time and is associated with a poor quality of life. Zebrafish are commonly used to investigate neurochemical, behavioral, and genetic parameters associated with ethanol (EtOH) exposure. However, few studies have used zebrafish as a model to investigate binge EtOH exposure. In order to elucidate the potential neurobehavioral impairments evoked by binge EtOH exposure in zebrafish, animals were immersed in 1.4% EtOH for 30 min three consecutive times with intervals of one week. Neurobehavioral parameters were analyzed immediately following the third exposure, as well as 2 and 9 days later. Brain choline acetyltransferase (ChAT) and acetylcholinesterase (AChE) activities were reduced 9 days after the treatment. Thiobarbituric acid-reactive species and dichlorodihydrofluorescein levels were increased immediately after the treatment, but both returned to normal levels 2 days after the treatment. Catalase and glutathione reductase were impaired 2 and 9 days after the treatment. No alteration was observed in superoxide dismutase and glutathione peroxidase activities. EtOH treatment did not alter brain expression of inflammatory genes such as il-1β, il-10, and tnf-α. Zebrafish displayed anxiolytic-like behavior immediately after the last exposure, though there was no behavioral alteration observed 9 days after the treatment. Therefore, binge EtOH exposure in zebrafish leads to long lasting brain cholinergic alteration, probably related to oxidative stress immediately after the exposure, which is independent of classical inflammatory markers.

Imaging with mass spectrometry, the next frontier in sphingolipid research? A discussion on where we stand and the possibilities ahead

In the last ten years, mass spectrometry (MS) has become the favored analytical technique for sphingolipid (SPL) analysis and measurements. Indeed MS has the unique ability to both acquire sensitive and quantitative measurements and to resolve the molecular complexity characteristic of SPL molecules, both across the different SPL families and within the same SPL family. Currently, two complementary MS-based approaches are used for lipid research: analysis of lipid extracts, mainly by infusion electrospray ionization (ESI), and mass spectrometry imaging (MSI) from a sample surface (i.e. intact tissue sections, cells, model membranes, thin layer chromatography plates) (Fig. 1). The first allows for sensitive and quantitative information about total lipid molecular species from a given specimen from which lipids have been extracted and chromatographically separated prior to the analysis; the second, albeit generally less quantitative and less specific in the identification of molecular species due to the complexity of the sample, allows for spatial information of lipid molecules from biological specimens. In the field of SPL research, MS analysis of lipid extracts from biological samples has been commonly utilized to implicate the role of these lipids in specific biological functions. On the other hand, the utilization of MSI in SPL research represents a more recent development that has started to provide interesting descriptive observations regarding the distribution of specific classes of SPLs within tissues. Thus, it is the aim of this review to discuss how MSI technology has been employed to extend the study of SPL metabolism and the type of information that has been obtained from model membranes, single cells and tissues. We envision this discussion as a complementary compendium to the excellent technical reviews recently published about the specifics of MSI technologies, including their application to SPL analysis (Fuchs et al., 2010; Berry et al., 2011; Ellis et al., 2013; Eberlin et al., 2011; Kraft and Klitzing, 2014).

[Neurotransmitter disturbances in some parts of the rat brain and their correction under chronic and intermittent alcohol intoxication]

The pool of key neuromediators and some neurotransmitter amino acids in cerebellum, hypothalamus and midbrain of rats exposed to chronic and different variants of interrupted alcohol intoxication was investigated. The most pronounced changes were recorded in midbrain. Chronic alcohol intoxication caused an increase in the concentrations of tyrosine, dopamine, 3,4-dihydroxyphenylacetic acid (DOPAC), noradrenaline, tryptophan, serotonin, GABA and aspartate in this part of the rat brain. Interrupted alcohol intoxication with 4 days interval is accompanied by an increase in the content of tyrosine, and noradrenaline. Interrupted alcohol intoxication with 1 day interval leaded to an increase in the concentrations of tyrosine, DOPAC, noradrenalin, tryptophan, GABA, glycine and aspartate. The amino acids composition "Titacin" had a pronounced normalizing effect in the midbrain under interrupted alcohol intoxication with 1 day interval.

Neurobiological Effects of Binge Drinking Help in Its Detection and Differential Diagnosis from Alcohol Dependence

The prevalence of binge drinking in the general population is 3-4 times higher than that of alcohol dependence. Neuroimaging studies show that binge drinking in adolescence impairs brain development and white matter integrity. Regions with reduced functional activity include the limbic system, ventral diencephalon, frontal lobe, and middle and inferior temporal lobes, whereas the right superior frontal and parietal lobes are typically hyperactivated. The observed activation of the frontoparietal areas might reflect the alternative memory system operating, whereas the reduced occipito-hippocampal response is associated with impaired visual and linguistic processing/learning. Some other findings from literature research include a decrease of N-acetylaspartate (NAA) in the frontal lobe and its increase in the parietal lobes, as well as the reduced components of event-related potentials, reflecting deficit in attention, working memory, inhibition, and executive functioning. Animal studies show that even a single day of binge drinking results in a neurodegeneration and reactive gliosis in the limbic cortex as well as in gene expression dysregulation and histone acetylation. Another biological evidence on binge drinking effect include inflammatory response, oxidative stress, formation of toxic ceramides, activation of caspase 3, and secretion of corticoliberin. Some of the binge drinking-induced cognitive abnormalities can be reversible after three weeks of abstinence. Although binge drinkers have a similar pattern of neuropsychological deficits with chronic alcohol consumers (mainly memory deficits), binge drinkers have prominent impairment of inhibitory control, which may be a marker of binge pattern of alcohol drinking. The optimal therapeutic strategies should target the inhibitory control processes to facilitate discontinuation of alcohol consumption and to block its possible progression to the alcohol dependence syndrome.

Role of the innate immune system in the neuropathological consequences induced by adolescent binge drinking

Adolescence is a critical stage of brain maturation in which important plastic and dynamic processes take place in different brain regions, leading to development of the adult brain. Ethanol drinking in adolescence disrupts brain plasticity and causes structural and functional changes in immature brain areas (prefrontal cortex, limbic system) that result in cognitive and behavioral deficits. These changes, along with secretion of sexual and stress-related hormones in adolescence, may impact self-control, decision making, and risk-taking behaviors that contribute to anxiety and initiation of alcohol consumption. New data support the participation of the neuroimmune system in the effects of ethanol on the developing and adult brain. This article reviews the potential pathological bases that underlie the effects of alcohol on the adolescent brain, such as the contribution of genetic background, the perturbation of epigenetic programming, and the influence of the neuroimmune response. Special emphasis is given to the actions of ethanol in the innate immune receptor toll-like receptor 4 (TLR4), since recent studies have demonstrated that by activating the inflammatory TLR4/NFκB signaling response in glial cells, binge drinking of ethanol triggers the release of cytokines/chemokines and free radicals, which exacerbate the immune response that causes neuroinflammation/neural damage as well as short- and long-term neurophysiological, cognitive, and behavioral dysfunction. Finally, potential treatments that target the neuroimmune response to treat the neuropathological and behavioral consequences of adolescent alcohol abuse are discussed.

[Indices of the antioxidant system and dopamine in blood plasma in the dynamics of microwave resonance therapy in patients with alcoholism]

AIM

To study effects of microwave resonance therapy (MWRT) on the level of dopamine and some indices of the antioxidant system of blood plasma in patients with alcohol dependence.

MATERIAL AND METHODS

Dopamine, reduced glutathione, activities of catalase and superoxidismutase (SOD) were measured in blood plasma of alcoholic patients (50 men) before and after therapy. Plasma of 25 physically and mentally healthy men matched for age was used as control.

RESULTS

In alcoholic patients in withdrawal state, the significant increase in dopamine (p=0.03), activity of catalase and SOD (p<0.05) as well as a decrease in reduced glutathione (p<0.01) in blood plasma in comparison with controls were found. The level of dopamine decreased significantly as after conventional therapy, as well after the therapy with addition of MWRT. After MWRT, the level of glutathione in blood plasma increased significantly and activities of catalase and SOD decreased practically up to the control level while after conventional therapy (without MWRT), the indices of the antioxidant system did not change significantly.

CONCLUSION

The inclusion of MWRT in complex treatment of patients with alcoholism contributes to the normalization of the activity of catalase and SOD and increases the level of reduced glutathione, but has no significant effect on blood plasma dopamine level.

Alcohol and Alzheimer's Disease-Does Alcohol Dependence Contribute to Beta-Amyloid Deposition, Neuroinflammation and Neurodegeneration in Alzheimer's Disease?

Aims

To investigate the underlying neurobiology between alcohol use, misuse and dependence and cognitive impairment, particularly Alzheimer's disease (AD).

Methods

Review of the literature using searches of Medline, Pubmed, EMBASE, PsycInfo, and meeting abstracts and presentations.

Results

The role of alcohol as a risk factor and contributor for cognitive decline associated with AD has received little attention. This is despite the high prevalence of alcohol use, the potential reversibility of a degree of cognitive impairment and the global burden of AD. Until now the focus has largely been on the toxic effects of alcohol, neuronal loss and the role of thiamine.

Conclusion

We propose alcohol adds to the cognitive burden seen in dementia through additional mechanisms to neurodegenerative processes or may contribute at various mechanistic points in the genesis and sustenance of AD pathology via neuroinflammation. We describe the common underlying neurobiology in alcohol and AD, and examine ways alcohol likely contributes to neuroinflammation directly via stimulation of Toll-like receptors and indirectly from small bowel changes, hepatic changes, withdrawal and traumatic brain injury to the pathogenesis of AD.

Short Summary

Alcohol use, misuse and dependence cause cognitive impairment. We propose alcohol adds to the cognitive burden seen in dementia through additional mechanisms to neurodegenerative processes or may contribute at various mechanistic points in the genesis and sustenance of AD pathology via neuroinflammation.

Synaptoimmunology - roles in health and disease

Mounting evidence suggests that the nervous and immune systems are intricately linked. Many proteins first identified in the immune system have since been detected at synapses, playing different roles in normal and pathological situations. In addition, novel immunological functions are emerging for proteins typically expressed at synapses. Under normal conditions, release of inflammatory mediators generally represents an adaptive and regulated response of the brain to immune signals. On the other hand, when immune challenge becomes prolonged and/or uncontrolled, the consequent inflammatory response leads to maladaptive synaptic plasticity and brain disorders. In this review, we will first provide a summary of the cell signaling pathways in neurons and immune cells. We will then examine how immunological mechanisms might influence synaptic function, and in particular synaptic plasticity, in the healthy and pathological CNS. A better understanding of neuro-immune system interactions in brain circuitries relevant to neuropsychiatric and neurological disorders should provide specific biomarkers to measure the status of the neuroimmunological response and help design novel neuroimmune-targeted therapeutics.

Does history of substance use disorder predict acute traumatic brain injury rehabilitation outcomes?

BACKGROUND/OBJECTIVE

The study explored whether premorbid substance use disorder (SUD) predicts acute traumatic brain injury (TBI) outcomes.

METHODS

143 participants with moderate (34.2%) and severe (65.8%) TBI were enrolled at two Level 1 trauma center inpatient brain injury rehabilitation units. Acute outcomes were measured with the Disability Rating Scale (DRS), the FIMTM; self and informant ratings of the Patient Competency Rating Scale (PCRS); self and family rating of the Frontal Systems Behavioral Scale (FrSBe), and the Neurobehavioral Rating Scale-Revised (NRS-R).

RESULTS

Hierarchical linear modeling revealed that SUD history significantly predicted trajectories of PCRS clinician ratings, PCRS self-family and PCRS self-clinician discrepancy scores, and more negative FrSBE family ratings. These findings indicate comparatively greater post-injury executive functions (EF) impairments, particularly self-awareness (SA) of injury-related deficits, for those with SUD history. No significant SUD*time interaction effect was found for FIM or NRS-R scores.

CONCLUSIONS

SUD history and TBI are associated with impaired SA and EF but their co-occurrence is not a consistent predictor of acute post-injury functional outcomes. Pre-morbid patient characteristics and rater expectations and biases may moderate associations between SA and recovery after TBI.

Alcohol-Induced Molecular Dysregulation in Human Embryonic Stem Cell-Derived Neural Precursor Cells

Adverse effect of alcohol on neural function has been well documented. Especially, the teratogenic effect of alcohol on neurodevelopment during embryogenesis has been demonstrated in various models, which could be a pathologic basis for fetal alcohol spectrum disorders (FASDs). While the developmental defects from alcohol abuse during gestation have been described, the specific mechanisms by which alcohol mediates these injuries have yet to be determined. Recent studies have shown that alcohol has significant effect on molecular and cellular regulatory mechanisms in embryonic stem cell (ESC) differentiation including genes involved in neural development. To test our hypothesis that alcohol induces molecular alterations during neural differentiation we have derived neural precursor cells from pluripotent human ESCs in the presence or absence of ethanol treatment. Genome-wide transcriptomic profiling identified molecular alterations induced by ethanol exposure during neural differentiation of hESCs into neural rosettes and neural precursor cell populations. The Database for Annotation, Visualization and Integrated Discovery (DAVID) functional analysis on significantly altered genes showed potential ethanol’s effect on JAK-STAT signaling pathway, neuroactive ligand-receptor interaction, Toll-like receptor (TLR) signaling pathway, cytokine-cytokine receptor interaction and regulation of autophagy. We have further quantitatively verified ethanol-induced alterations of selected candidate genes. Among verified genes we further examined the expression of P2RX3, which is associated with nociception, a peripheral pain response. We found ethanol significantly reduced the level of P2RX3 in undifferentiated hESCs, but induced the level of P2RX3 mRNA and protein in hESC-derived NPCs. Our result suggests ethanol-induced dysregulation of P2RX3 along with alterations in molecules involved in neural activity such as neuroactive ligand-receptor interaction may be a molecular event associated with alcohol-related peripheral neuropathy of an enhanced nociceptive response.

Functional and structural brain connectivity of young binge drinkers: a follow-up study

Adolescence is a period of ongoing brain maturation characterized by hierarchical changes in the functional and structural networks. For this reason, the young brain is particularly vulnerable to the toxic effects of alcohol. Nowadays, binge drinking is a pattern of alcohol consumption increasingly prevalent among adolescents. The aim of the present study is to evaluate the evolution of the functional and anatomical connectivity of the Default Mode Network (DMN) in young binge drinkers along two years. Magnetoencephalography signal during eyes closed resting state as well as Diffusion Tensor Imaging (DTI) were acquired twice within a 2-year interval from 39 undergraduate students (22 controls, 17 binge drinkers) with neither personal nor family history of alcoholism. The group comparison showed that, after maintaining a binge drinking pattern along at least two years, binge drinkers displayed an increased brain connectivity of the DMN in comparison with the control group. On the other hand, the structural connectivity did not show significant differences neither between groups nor over the time. These findings point out that a continued pattern of binge drinking leads to functional alterations in the normal brain maturation process, even before anatomical changes can be detected.

Utilizing mutual information for detecting rare and common variants associated with a categorical trait

Background. Genome-wide association studies have succeeded in detecting novel common variants which associate with complex diseases. As a result of the fast changes in next generation sequencing technology, a large number of sequencing data are generated, which offers great opportunities to identify rare variants that could explain a larger proportion of missing heritability. Many effective and powerful methods are proposed, although they are usually limited to continuous, dichotomous or ordinal traits. Notice that traits having nominal categorical features are commonly observed in complex diseases, especially in mental disorders, which motivates the incorporation of the characteristics of the categorical trait into association studies with rare and common variants.

Methods. We construct two simple and intuitive nonparametric tests, MIT and aMIT, based on mutual information for detecting association between genetic variants in a gene or region and a categorical trait. MIT and aMIT can gauge the difference among the distributions of rare and common variants across a region given every categorical trait value. If there is little association between variants and a categorical trait, MIT or aMIT approximately equals zero. The larger the difference in distributions, the greater values MIT and aMIT have. Therefore, MIT and aMIT have the potential for detecting functional variants.

Results.We checked the validity of proposed statistics and compared them to the existing ones through extensive simulation studies with varied combinations of the numbers of variants of rare causal, rare non-causal, common causal, and common non-causal, deleterious and protective, various minor allele frequencies and different levels of linkage disequilibrium. The results show our methods have higher statistical power than conventional ones, including the likelihood based score test, in most cases: (1) there are multiple genetic variants in a gene or region; (2) both protective and deleterious variants are present; (3) there exist rare and common variants; and (4) more than half of the variants are neutral. The proposed tests are applied to the data from Collaborative Studies on Genetics of Alcoholism, and a competent performance is exhibited therein.

Discussion. As a complementary to the existing methods mainly focusing on quantitative traits, this study provides the nonparametric tests MIT and aMIT for detecting variants associated with categorical trait. Furthermore, we plan to investigate the association between rare variants and multiple categorical traits.

Evaluation of acute effects of melatonin on ethanol drinking in ethanol naïve rats

Objective:

The objective was to evaluate the acute effect of melatonin on ethanol drinking in ethanol naïve rats and to determine the specificity of the effect of melatonin on ethanol intake as compared to an intake of plain tap water or sugar water.

Materials and Methods:

A total of three experiments (2 weeks duration each) using different drinking solutions (ethanol, plain tap water, sugar water) was conducted in individually housed male wistar rats of 5 weeks age. Each animal had access to bottles containing drinking solutions for 2 h a day. In each experiment, on day 1, day 2, day 4, day 5, day 8, day 9, day 11, day 12 rats received drinking solutions. Each individual rat received single doses of saline, melatonin (50 mg and 100 mg/kg), and naltrexone on day 2, 5, 9, and 12, 1-h before receiving drinking solution. The order of drug administration is permuted such a way that each animal received the drugs in a different order in different experiments.

Results:

Melatonin has significantly decreased ethanol consumption by the rats and effect is dose-dependent. Naltrexone also has caused a significant reduction in the ethanol consumption. The maximum reduction in ethanol consumption was seen with melatonin 100 mg/kg dose compared to melatonin 50 mg/kg and naltrexone. There was no statistically significant effect of melatonin on plain water and sugar solution intake.

Conclusions:

Melatonin decreases ethanol consumption in ethanol naïve rats. The effect of melatonin is similar to naltrexone affecting selectively ethanol consumption, but not plain water and sugar water consumption.

Sustained alterations in neuroimmune gene expression after daily, but not intermittent, alcohol exposure

Acute ethanol intoxication is associated with Rapid Alterations in Neuroimmune Gene Expression (RANGE), including increased Interleukin (IL)-6 and Nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, alpha (IκBα), and suppressed IL-1β and Tumor necrosis factor (TNF) α, yet little is known about adaptations in cytokines across the first few ethanol exposures. Thus, the present studies examined central cytokines during intoxication (3h post-ethanol) following 2, 4 or 6 intragastric ethanol challenges (4g/kg) delivered either daily or every-other-day (EOD). Subsequent analyses of blood ethanol concentrations (BECs) and corticosterone were performed to determine whether the schedule of ethanol delivery would alter the pharmacokinetics of, or general sensitivity to, subacute ethanol exposure. As expected, ethanol led to robust increases in IL-6 and IκBα gene expression in hippocampus, amygdala and bed nucleus of the stria terminalis (BNST), whereas IL-1β and TNFα were suppressed, thereby replicating our prior work. Ethanol-dependent increases in IL-6 and IκBα remained significant in all structures - even after 6 days of ethanol. When these doses were administered EOD, modest IL-6 increases in BNST were observed, with TNFα and IL-1β suppressed exclusively in the hippocampus. Analysis of BECs revealed a small but significant reduction in ethanol after 4 EOD exposures - an effect which was not observed when ethanol was delivered after 6 daily intubations. These findings suggest that ethanol-induced RANGE effects are not simply a function of ethanol load per se, and underscore the critical role that ethanol dosing interval plays in determining the neuroimmune consequences of alcohol.

Drugs as instruments: a new framework for non-addictive psychoactive drug use

Most people who are regular consumers of psychoactive drugs are not drug addicts, nor will they ever become addicts. In neurobiological theories, non-addictive drug consumption is acknowledged only as a "necessary" prerequisite for addiction, but not as a stable and widespread behavior in its own right. This target article proposes a new neurobiological framework theory for non-addictive psychoactive drug consumption, introducing the concept of "drug instrumentalization." Psychoactive drugs are consumed for their effects on mental states. Humans are able to learn that mental states can be changed on purpose by drugs, in order to facilitate other, non-drug-related behaviors. We discuss specific "instrumentalization goals" and outline neurobiological mechanisms of how major classes of psychoactive drugs change mental states and serve non-drug-related behaviors. We argue that drug instrumentalization behavior may provide a functional adaptation to modern environments based on a historical selection for learning mechanisms that allow the dynamic modification of consummatory behavior. It is assumed that in order to effectively instrumentalize psychoactive drugs, the establishment of and retrieval from a drug memory is required. Here, we propose a new classification of different drug memory subtypes and discuss how they interact during drug instrumentalization learning and retrieval. Understanding the everyday utility and the learning mechanisms of non-addictive psychotropic drug use may help to prevent abuse and the transition to drug addiction in the future.

URB597 inhibits oxidative stress induced by alcohol binging in the prefrontal cortex of adolescent rats

Heavy episodic drinking (binging), which is highly prevalent among teenagers, results in oxidative damage. Because the prefrontal cortex (PFC) is not completely mature in adolescents, this brain region may be more vulnerable to the effects of alcohol during adolescence. As endocannabinoids may protect the immature PFC from the harmful effects of high doses of alcohol, this study investigated the effect of the fatty acid amide hydrolase (FAAH) inhibitor URB597 on oxidative stress induced by acute or chronic binge alcohol intake in adolescent rats. At 40min after intraperitoneal pre-treatment with URB597 (0.3mg/kg) or vehicle (Veh), ethanol (EtOH; 3 or 6g/kg, intragastrically) or distilled water (DW) was administered in 3 consecutive sessions (acute binging) or 3 consecutive sessions over 4 weeks (chronic binging). Oxidative stress in PFC slices in situ was measured by dihydroethidium fluorescence staining. At the higher EtOH dose (6g/kg), pre-treatment with URB597 significantly reduced (p<0.01) the production of superoxide anions in the PFC after acute (42.8% decrease) and chronic binge EtOH consumption (44.9% decrease) compared with pre-treatment with Veh. As URB597 decreases anandamide metabolism, this evidence shows an antioxidant effect of endocannabinoids to suppress acute and chronic binge alcohol intake-induced oxidative stress in the PFC of adolescent rats.

Interactions between chronic ethanol consumption and thiamine deficiency on neural plasticity, spatial memory, and cognitive flexibility

BACKGROUND

Many alcoholics display moderate to severe cognitive dysfunction accompanied by brain pathology. A factor confounded with prolonged heavy alcohol consumption is poor nutrition, and many alcoholics are thiamine deficient. Thus, thiamine deficiency (TD) has emerged as a key factor underlying alcohol-related brain damage (ARBD). TD in humans can lead to Wernicke Encephalitis that can progress into Wernicke-Korsakoff syndrome and these disorders have a high prevalence among alcoholics. Animal models are critical for determining the exact contributions of ethanol (EtOH)- and TD-induced neurotoxicity, as well as the interactions of those factors to brain and cognitive dysfunction.

METHODS

Adult rats were randomly assigned to 1 of 6 treatment conditions: chronic EtOH treatment (CET) where rats consumed a 20% v/v solution of EtOH over 6 months; severe pyrithiamine-induced TD (PTD-moderate acute stage); moderate PTD (PTD-early acute stage); moderate PTD followed by CET (PTD-CET); moderate PTD during CET (CET-PTD); and pair-fed (PF) control. After recovery from treatment, all rats were tested on spontaneous alternation and attentional set-shifting. After behavioral testing, brains were harvested for determination of mature brain-derived neurotrophic factor (BDNF) and thalamic pathology.

RESULTS

Moderate TD combined with CET, regardless of treatment order, produced significant impairments in spatial memory, cognitive flexibility, and reductions in brain plasticity as measured by BDNF levels in the frontal cortex and hippocampus. These alterations are greater than those seen in moderate TD alone, and the synergistic effects of moderate TD with CET lead to a unique cognitive profile. However, CET did not exacerbate thalamic pathology seen after moderate TD.

CONCLUSIONS

These data support the emerging theory that subclinical TD during chronic heavy alcohol consumption is critical for the development of significant cognitive impairment associated with ARBD.

Binge alcohol drinking elicits persistent negative affect in mice

Cessation from chronic alcohol abuse often produces a dysphoric state that can persist into protracted withdrawal. This dysphoric state is theorized to function as a negative reinforcer that maintains excessive alcohol consumption and/or precipitates relapse in those struggling to abstain from alcohol. However, we know relatively little regarding the impact of cessation from binge drinking on behavioral measures of negative affect and related neurobiology. Male C57BL/6J mice were given access to unsweetened 20% alcohol for 6 weeks under modified Drinking-in-the-dark procedures, followed by behavioral testing beginning either 1 or 21 days into withdrawal. Mice were administered a behavioral test battery consisting of: the elevated plus maze, light/dark box, novel object test, marble burying test, Porsolt forced swim test and sucrose preference test to assess anxiogenic and depressive signs. Egr1 immunostaining was used to quantify cellular activity within the central nucleus of the amygdala (CEA), basolateral amygdala (BLA), bed nucleus of the stria terminalis (BNST), and the nucleus accumbens (Acb) shell (AcbSh) and core (AcbC). Compared to water controls, alcohol-drinking mice exhibited higher indices of emotionality in the majority of behavioral assays. The hyper-emotionality exhibited by binge drinking mice was apparent at both withdrawal time-points and correlated with higher Egr1+ cell counts in the CEA and BNST, compared to controls. These data show that affective symptoms emerge very early after cessation of binge drinking and persist into protracted withdrawal. A history of binge drinking is capable of producing enduring neuroadaptations within brain circuits mediating emotional arousal.

Repeated Binge Drinking Increases Perineuronal Nets in the Insular Cortex

BACKGROUND

Alcohol exposure leads to changes in the extracellular matrix (ECM) in the brain, which profoundly impacts neuronal plasticity. Perineuronal nets (PNs) are specialized ECM structures that enclose subpopulations of neurons in the cortex. Adolescent exposure to alcohol induces long-lasting increases in the expression of PN components in the cortex in adult mice. However, it has not been determined whether binge alcohol exposure in young adults alters PNs. Here, we examined PNs and their core components in the insula and primary motor cortex after repeated binge-like ethanol (EtOH) consumption in adult mice.

METHODS

The 4-day drinking in the dark (DID) procedure was performed in mice for 1 or 6 weeks to model binge alcohol consumption. The impact of EtOH drinking on PNs was examined by fluorescent staining of brain sections using a marker for PNs, Wisteria floribunda agglutinin (WFA). In another set of experiments, cortex was dissected and Western blots and real-time quantitative polymerase chain reaction were performed to evaluate the expression of the PN proteins aggrecan, brevican, and phosphacan.

RESULTS

Binge-like EtOH drinking for 6 weeks caused a significant increase in PNs in the insula, as measured by WFA binding. Aggrecan, brevican, and phosphacan protein expression, and aggrecan mRNA expression, were also elevated in the insula after 6 weeks of EtOH drinking. In contrast, expression of PN components did not change after 1 week of DID. The increase in PNs appears to be specific to the insula, because alterations were not observed in the primary motor cortex.

CONCLUSIONS

Our results provide the first evidence that insular PNs increase after long-term binge drinking. The insula mediates compulsive alcohol use. As PNs influence neuronal firing and plasticity, increased PNs in the insula after multiple binge cycles may contribute to restricted neuronal plasticity and lead to the development of compulsive alcohol use.

Eyes on the price: Human culture and its teaching

Kline proposes an evolutionary framework for teaching as a major base of human culture, in which she outlines how different types of teaching may solve adaptive problems with a focus on human behavior. Here it is argued that the ability to teach and the different types of teaching behavior may not only solve adaptive problems, but also create them.

Impact of family history of alcoholism on glutamine/glutamate ratio in anterior cingulate cortex in substance-naïve adolescents

Neuroimaging studies of individuals with family histories of alcoholism provide evidence suggesting neurobiological risk factors for alcoholism. Youth family history positive (FH+) for alcoholism exhibit increased impulsivity compared to family history negative (FH-) peers in conjunction with altered functional activation in prefrontal cortex, including anterior cingulate cortex (ACC). This study examined glutamate (Glu) and glutamine (Gln), amino acids vital to protein synthesis, cellular metabolism and neurotransmission, acquired from ACC and parieto-occipital cortex (POC) using magnetic resonance spectroscopy (MRS) at 4T. Participants were 28 adolescents (13 male, 12-14 yrs) and 31 emerging adults (16 male, 18-25 yrs), stratified into FH- and FH+ groups. Significantly higher ACC Gln/Glu was observed in emerging adults versus adolescents in FH- but not FH+ groups. In FH- adolescents, higher impulsivity was significantly associated with higher ACC Gln/Glu. In FH+ emerging adults, higher impulsivity was negatively associated with ACC Gln/Glu. No differences or associations were observed for POC. These findings provide preliminary evidence that family history of alcoholism is associated with a neurochemical profile that may influence normative age differences in glutamatergic metabolites and their association with impulse control, which together could confer greater genetic risk of addiction later in life.