Alcohol use disorders and current pharmacological therapies: the role of GABA(A) receptors

Baseline gut microbiome and metabolites are correlated with changes in alcohol consumption in participants in a randomized Zonisamide clinical trial

Development and severity of alcohol use disorder (AUD) has been linked to variations in gut microbiota and their associated metabolites in both animal and human studies. However, the involvement of the gut microbiome in alcohol consumption of individuals with AUD undergoing treatment remains unclear. To address this, stool samples (n = 32) were collected at screening (baseline) and trial completion from a double-blind, placebo-controlled trial of zonisamide in individuals with AUD. Alcohol consumption was measured both at baseline and endpoint of 16-week trial period. Fecal microbiome was analyzed via 16 S rRNA sequencing and metabolome via untargeted LC-MS. Both sex (p = 0.003) and psychotropic medication usage (p = 0.025) are associated with baseline microbiome composition. The relative abundance of 11 genera at baseline was correlated with percent drinking reduction (p.adj < 0.1). Overall microbiome community structure at baseline differed between high and low reducers of alcohol drinking (67-100% and 0-33% drinking reduction, respectively; p = 0.034). A positive relationship between baseline fecal GABA levels and percent drinking reduction (R = 0.43, p.adj < 0.07) was identified by microbiome function prediction and confirmed by ELISA and metabolomics. Metabolomics analysis also found 3-hydroxykynurenine, a neurotoxic intermediate metabolite of tryptophan, was negatively correlated with drinking reduction (p.adj = 0.047), and was over-represented in low reducers. These findings highlight importance of baseline microbiome and amino acid metabolites in drinking reduction in AUD participants undergoing zonisamide treatment. It may hold significant value as a predictive tool in clinical settings to better personalize intervention and improve reduction in alcohol consumption in future.

Oleanolic acid protects ethanol-induced memory impairments

A moderate amount of ethanol (EtOH) intake can lower the incidence of various cardiovascular disease but can result in neuropsychiatric issues during adolescence. EtOH acts on GABAA receptor, which can slow down neurotransmission and lead to changes in synaptic functions. These neurological changes due to EtOH can result in transient memory loss and may increase the risk of developing various neurological and psychiatric disorders such as dementia. Therefore, there is a need for strategies to overcome EtOH-induced brain dysfunctions. In this study, we investigated the effects of oleanolic acid (OA) on EtOH-induced memory impairment. OA blocked functional impairment of N-methyl-D-aspartate receptors (NMDAR), which are a key mechanism in EtOH-induced memory impairments. OA inhibited the removal of the major subunit of NMDAR, NR2a, from synapses induced by EtOH. Based on this, OA inhibited the impairment of object recognition memory caused by EtOH. Although OA failed to modulate the blood alcohol and acetaldehyde levels in EtOH-treated mice, OA blocked EtOH-induced increase in brain allopregnalone level with reducing 5α-reductase level. These results indicate that OA inhibits EtOH-induced memory impairment by regulating NMDAR function and passably modulates neurosteroid system.

Expecting medication misuse: a proactive approach to drug discovery to prevent fatal overdose

Misuse of central nervous system (CNS) depressants (alprazolam, fentanyl, etc.) is a major cause of fatal overdose, with a high prevalence of deaths involving polydrug interactions from the victim's own prescriptions. Thus, there is an urgent need to improve the safety of CNS depressants to prevent fatalities. Pharmacological pursuits aiming to prevent harm through the design of non-addictive alternatives have either failed before clinical trials or produced mediocre treatment alternatives. Therefore, we propose a new perspective for medicinal chemists: rather than aiming to prevent misuse, we must design new central nervous system (CNS) depressants under the expectation of misuse. By shifting the design focus to partial modulators rather than full agonists, we can develop novel chemical entities (NCEs) that intrinsically minimize physical harm caused by misuse without sacrificing therapeutic efficacy. In this perspective, we provide an overview of the two most widely misused classes of medications (opioid and GABAA receptor modulators) in relation to pharmacodynamic properties and clinical outcomes. We then suggest a drug discovery pathway focused on physiological parameters. It is our opinion that this approach would dramatically decrease the lethality of overdose and improve outcomes of treatments for pain, anxiety, and withdrawal from alcohol, benzodiazepines, and opioids.

Role of Nanomedicine in Transforming Pharmacotherapy for Substance Use Disorder (SUD)

The field of nanomedicine offers revolutionary potential to reshape the discovery and development of therapeutics for diverse human diseases. However, its application has been limited in improving Substance Use Disorders (SUDs), which represent a profound public health crisis, including major types such as opioid, alcohol, stimulant, and cannabis use disorders. Pharmacotherapy, a cornerstone of SUD management, has reduced morbidity, mortality, and the societal impact of addiction, though its efficacy has ranged from none to moderate. Thus, there is a major unmet need to transform SUD pharmacotherapy to curb the epidemic of addiction. This article explores the potential roles of nanomedicine-inspired precision-targeted drug delivery, sustained release, and combination therapies to increase therapeutic efficacy and minimize side effects. Additionally, it discusses innovative mechanisms that align with the neurobiological complexities of addiction and synergistic approaches that integrate nanomedicine with behavioral interventions, device-based therapies, and emerging modalities such as immunotherapy and neurostimulation. Despite these advancements, barriers such as treatment accessibility, adherence challenges, and inequitable resource distribution persist, particularly in underserved populations. By harnessing the transformative capabilities of nanomedicine and integrating it into holistic, equitable, and personalized care frameworks, this review highlights a path forward to revolutionize the SUD pharmacotherapy landscape. The article underscores the need for continued nano-SUD pharmacotherapy research and the development of strategies to alleviate the substantial burden of addiction on individuals, families, and society.

Intestinal Microbiomics and Liver Metabolomics Insights into the Ameliorative Effects of Selenium-Enriched Lactobacillus fermentum FZU3103 on Alcohol-Induced Liver Injury in Mice

In this study, we investigated the ameliorative effects of selenium-enriched Lactobacillus fermentum FZU3103 (Lf@Se) and its pathway on alcoholic liver injury (ALI) in mice. The results showed that Lf@Se was superior to Lf and inorganic selenium in alleviating ALI. Oral Lf@Se effectively prevented lipid metabolism disorders, improved liver function, promoted alcohol metabolism, and alleviated liver oxidative damage in mice. 16S amplicons sequencing indicated that Lf@Se intervention modulated intestinal flora homeostasis by increasing (decreasing) the abundance of beneficial bacteria (harmful bacteria), which is associated with the improvement of liver function. Besides, Lf@Se intervention altered the liver metabolic profile, and the characteristic biomarkers were mainly involved in tyrosine metabolism, retinol metabolism, galactose metabolism, and primary bile acid biosynthesis. Additionally, Lf@Se intervention regulated liver gene expression for lipid metabolism and oxidative stress. Western blot analysis revealed increased expression levels of intestinal tight junction proteins after Lf@Se intervention, thereby ameliorating alcohol-induced intestinal barrier damage.

Modern pharmacotherapy guidance for treating alcohol use disorders

INTRODUCTION

Alcohol use disorder (AUD) is prevalent and recognized as a chronic, relapsing disorder. Even though effective treatment options are available, AUD is strongly undertreated. As adjuvant treatment strategies accompanying psychosocial treatments, pharmacological strategies can increase the efficacy of AUD treatment options.

AREAS COVERED

After giving a brief update of epidemiology, neurobiology and treatment rationales for AUD, the review outlines pharmacological interventions against the background of current evidence. These include approved substances like naltrexone, nalmefene, acamprosate and disulfiram, second line medications like topiramate, baclofen and varenicline and novel approaches like hallucinogens. The review refers to the primary database on pharmacotherapies for AUD and to findings from pairwise and network meta-analyses. It illustrates effects of pharmacotherapies for AUD on different outcomes and assesses risks and benefits of treatment strategies. Search has been conducted in PubMed using the substance name or related categories (such as anti-craving or relapse prevention) as key words.

EXPERT OPINION

Improved understanding of AUDs neurocircuitry expands the range of available pharmacotherapeutic strategies for supporting abstinence and drinking reduction. Pharmacotherapies for AUD can be improved by understanding differences in treatment response. Matching different treatment approaches to individual needs can challenge the view of alcohol dependence as a lifelong disorder.

Dream of the Endless: Special Considerations in Procedural Sedation

Procedural sedation and analgesia (PSAA) is integral to facilitating painful and anxiety-inducing medical procedures in the emergency department (ED). Optimal PSAA enhances procedural success and improves both patient and provider satisfaction. The selection of appropriate sedative and analgesic agents, routes, and dosages, which depend on various patient- and procedure-specific factors is a complex process. Alternative routes of administration, such as intranasal, intramuscular, and oral, are all options, each with their own inherent benefits and limitations. It is important for providers to take into account patient-specific considerations, including age, medical history, body weight composition, and pregnancy, which can significantly impact PSAA effectiveness and safety. Implementation strategies targeted to minimize medication errors and optimize workflow are also important considerations in PSAA. By adopting a comprehensive and evidence-based approach, health care providers can navigate the intricacies of PSAA and ensure the best possible care for patients in the ED.

Kratom Alkaloids for the Treatment of Alcohol Use Disorder

Alcohol use disorder (AUD) accounts for nearly 4.7% of all deaths and imposes a huge economic burden on society. Despite the magnitude of the problem, only a few Food and Drug Administration (FDA)/European Medicines Agency (EMA)-approved drugs are currently available for AUD treatment. Despite being efficacious, these drugs are not without problems, adverse effects being a major issue. That combined with medication adherence and compliance problems, the discovery of new drugs is imperative. Kratom (Mitragyna speciosa) alkaloids and some of their semisynthetic derivatives reduce alcohol intake and alcohol-induced withdrawal symptoms in animal models. These compounds act as G-protein-biased ligands at the μ-, δ-, and κ-opioid receptors, and their effect in reducing alcohol intake is mediated through the δ-opioid receptor. This article provides a critical overview of recent preclinical studies involving kratom alkaloids for AUD treatment, with a particular focus on the pharmacology and medicinal chemistry of these alkaloids. FDA/EMA approved drugs, repurposed drugs, and plant-based compounds for the treatment of AUD are briefly mentioned. Finally, important caveats and future research directions on this topic are discussed.

Clinical applications of small-molecule GABAAR modulators for neurological disorders

Gamma-aminobutyric acid type A receptor (GABAAR) modulators are crucial in treating neurological and psychiatric disorders, including epilepsy, anxiety, insomnia, and depression. This review examines the synthetic approaches and clinical applications of representative small-molecule GABAAR modulators. Benzodiazepines, such as Diazepam, are well-known positive allosteric modulators (PAMs) that enhance GABAAR function, providing therapeutic effects but also associated with side effects like sedation and dependence. Non-benzodiazepine modulators, including Z-drugs like Zolpidem and Zaleplon, offer improved selectivity for the α1 subunit of GABAAR, reducing some of these side effects. Neurosteroids such as allopregnanolone and its synthetic analogs, including Brexanolone, have emerged as potent GABAAR modulators with applications in conditions like postpartum depression and refractory epilepsy. Advances in molecular biology and pharmacology have facilitated the development of isoform-specific modulators, potentially reducing off-target effects and enhancing therapeutic profiles. Additionally, combining GABAAR modulators with other therapeutic agents has shown promise in enhancing efficacy and minimizing side effects. This review highlights the design strategies, pharmacodynamics, clinical efficacy, and safety profiles of these compounds, emphasizing the opportunities for developing novel GABAAR modulators with improved therapeutic outcomes.

5,7,3',4',5'-Pentamethoxyflavone, a Flavonoid Monomer Extracted From Murraya paniculata (L.) Jack, Alleviates Anxiety Through the A2AR/Gephyrin/GABRA2 Pathway

The sedative and hypnotic properties of 5,7,3',4',5'-pentamethoxyflavone (PMF), a monomer extracted from the leaves of Murraya paniculata (L.) Jack, have been reported. However, the role of PMFs in the development of anxiety remains uncertain. An anxiety model was developed using chronic unpredictable mild stimulation (CUMS). Kunming mice were randomly allocated to the following groups: control, CUMS, PMF (50 mg/kg), PMF (100 mg/kg), and diazepam (3 mg/kg). The anxiolytic effects of PMFs were evaluated using elevated plus maze (EPM) test and open field test (OFT). Enzyme-linked immunosorbent assay (ELISA) kits were used to analyze the serum levels of corticosterone (CORT), 5-hydroxytryptamine (5-HT), gamma-aminobutyric acid (GABA), and cyclic adenosine monophosphate (cAMP) in the hippocampus. High-throughput-16S rRNA sequencing was performed to investigate its effect on the composition of the gut microbiota. Subsequently, western blotting was performed to assess the expression of GABAergic synaptic-associated proteins. PMF effectively mitigated CUMS-induced anxiety-like behavior. Further examination revealed that PMF treatment ameliorated dysfunction of the hypothalamic-pituitary-adrenal (HPA) axis and increased 5-HT and GABA levels in the hippocampus. Notably, the ability of PMF to maintain the stability of GABAergic synapses by enhancing the species composition of the gut microbiota and acting on the adenosine a2a receptor (A2AR)/gephyrin/gamma-aminobutyric acid A receptor alpha 2 (GABRA2) pathway revealed a previously unrecognized mechanism for the anxiolytic effect of PMF. These findings suggest that PMF enhances the expression of A2AR, preserves GABAergic synaptic stability, and reduces anxiety by modulating the microbiota composition. Thus, it holds promise as an anxiolytic agent.

Innovative Formulation Platform: Paving the Way for Superior Protein Therapeutics with Enhanced Efficacy and Broadened Applications

Protein therapeutics offer high therapeutic potency and specificity; the broader adoptions and development of protein therapeutics, however, have been constricted by their intrinsic limitations such as inadequate stability, immunogenicity, suboptimal pharmacokinetics and biodistribution, and off-target effects. This review describes a platform technology that formulates individual protein molecules with a thin formulation layer of crosslinked polymers, which confers the protein therapeutics with high activity, enhanced stability, controlled release capability, reduced immunogenicity, improved pharmacokinetics and biodistribution, and ability to cross the blood brain barriers. Based on currently approved protein therapeutics, this formulating platform affords the development of a vast family of superior protein therapeutics with improved efficacy and broadened indications at significantly reduced cost.

Benefits of exercise on cognitive impairment in alcohol use disorder following alcohol withdrawal

Although most cognitive impairments induced by prolonged alcohol consumption tend to improve within the initial months of abstinence, there is evidence suggesting certain cognitive deficits may persist. This study aimed to investigate the impact of aerobic exercise on learning and memory in alcohol use disorder (AUD) mice following a period of abstinence from alcohol. We also sought to assess the levels of monoamine neurotransmitters in the hippocampus. To this end, we established an AUD mouse model through a two-bottle choice (sucrose fading mode and normal mode) and chronic intermittent alcohol vapor (combined with intraperitoneal injection) and randomly allocated mice into exercise groups to undergo treadmill training. Learning and memory abilities were assessed through the Morris water maze test and spontaneous activity was evaluated using the open field test. The levels of dopamine, norepinephrine, serotonin, and brain-derived neurotrophic factor in the hippocampus were quantified using enzyme-linked immunoassay (ELISA) kits. The findings reveal that after cessation of alcohol consumption, learning and memory abilities in AUD mice did not completely return to normal levels. The observed enhancement of cognitive functions in AUD mice through aerobic exercise may be attributed to restoring levels of monoamine neurotransmitters in the hippocampus, boosting brain-derived neurotrophic factor (BDNF) concentrations, and facilitating an increase in hippocampal mass. These results offer empirical evidence to support aerobic exercise as a viable therapeutic strategy to alleviate cognitive deficits associated with AUD.

Synthesis of Ganoderic Acids Loaded Zein-Chitosan Nanoparticles and Evaluation of Their Hepatoprotective Effect on Mice Given Excessive Alcohol

Ganoderma lucidum, used in East Asia for its health benefits, contains ganoderic acids (GA) which have various pharmacological activities but are limited by poor water solubility and low oral bioaccessibility. This study synthesized and characterized ganoderic acids loaded zein-chitosan nanoparticles (GA-NPs), and investigated its advantages in alleviating alcoholic liver injury (ALI) in mice model. The GA-NPs demonstrated high encapsulation efficiency (92.68%), small particle size (177.20 nm), and a +29.53 mV zeta potential. The experimental results of alcohol-induced liver injury mouse model showed that GA-NPs significantly improved liver metabolic function, reduced alcohol-induced liver oxidative stress in liver by decreasing lactate dehydrogenase activity and malondialdehyde level, while increasing the activities of liver antioxidant enzymes and alcohol dehydrogenase. Moreover, GA-NPs were favorable to ameliorate intestinal microbiota dysbiosis in mice exposed to alcohol by increasing the proportion of probiotics such as Romboutsia, Faecalibaculum, Bifidobacterium and Turicibacter, etc., which were highly correlated with the improvement of liver function. Furthermore, GA-NPs modulated the mRNA expression related to ethanol metabolism, oxidative stress and lipid metabolism. Conclusively, this study revealed that GA-NPs have stronger hepatoprotective effects than non-encapsulated ganoderic acids on alleviating ALI by regulating intestinal microbiota and liver metabolism.

Region-Specific Gene Expression Changes Associated with Oleoylethanolamide-Induced Attenuation of Alcohol Self-Administration

Oleoylethanolamide (OEA) is a lipid with anti-inflammatory activity that modulates multiple reward-related behaviors. Previous studies have shown that OEA treatment reduces alcohol self-administration (SA) while inhibiting alcohol-induced inflammatory signaling. Nevertheless, the specific mechanisms that OEA targets to achieve these effects have not been widely explored. Here, we tested the effects of OEA treatment during alcohol SA, extinction or previous to cue-induced reinstatement of alcohol seeking. In addition, we measured gene expression changes in the striatum and hippocampus of relevant receptors for alcohol consumption (Drd1, Drd2, Cnr1, Oprm) as well as immune-related proteins (Il-6, Il-1β, Tlr4) and the brain-derived neurotrophic factor (Bdnf). Our results confirmed that when administered contingently, systemic OEA administration reduced alcohol SA and attenuated cue-induced reinstatement. Interestingly, we also observed that OEA treatment reduced the number of sessions needed for the extinction of alcohol seeking. Biochemical analyses showed that OEA induced gene expression changes in dopamine and cannabinoid receptors in the striatum and hippocampus. In addition, OEA treatment modulated the long-term immune response and increased Bdnf expression. These results suggest that boosting OEA levels may be an effective strategy for reducing alcohol SA and preventing relapse.

Forskolin reverses the O-GlcNAcylation dependent decrease in GABAAR current amplitude at hippocampal synapses possibly at a neurosteroid site on GABAARs

GABAergic transmission is influenced by post-translational modifications, like phosphorylation, impacting channel conductance, allosteric modulator sensitivity, and membrane trafficking. O-GlcNAcylation is a post-translational modification involving the O-linked attachment of β-N-acetylglucosamine on serine/threonine residues. Previously we reported an acute increase in O-GlcNAcylation elicits a long-term depression of evoked GABAAR inhibitory postsynaptic currents (eIPSCs) onto hippocampal principal cells. Importantly, O-GlcNAcylation and phosphorylation can co-occur or compete for the same residue; whether they interact in modulating GABAergic IPSCs is unknown. We tested this by recording IPSCs from hippocampal principal cells and pharmacologically increased O-GlcNAcylation, before or after increasing serine phosphorylation using the adenylate cyclase activator, forskolin. Although forskolin had no significant effect on baseline eIPSC amplitude, we found that a prior increase in O-GlcNAcylation unmasks a forskolin-dependent increase in eIPSC amplitude, reversing the O-GlcNAc-induced eIPSC depression. Inhibition of adenylate cyclase or protein kinase A did not prevent the potentiating effect of forskolin, indicating serine phosphorylation is not the mechanism. Surprisingly, increasing O-GlcNAcylation also unmasked a potentiating effect of the neurosteroids 5α-pregnane-3α,21-diol-20-one (THDOC) and progesterone on eIPSC amplitude in about half of the recorded cells, mimicking forskolin. Our findings show that under conditions of heightened O-GlcNAcylation, the neurosteroid site on synaptic GABAARs is possibly accessible to agonists, permitting strengthening of synaptic inhibition.

Preparation of Pueraria lobata Root-Derived Exosome-Like Nanovesicles and Evaluation of Their Effects on Mitigating Alcoholic Intoxication and Promoting Alcohol Metabolism in Mice

Purpose

Pueraria lobata (P. lobata), a dual-purpose food and medicine, displays limited efficacy in alcohol detoxification and liver protection, with previous research primarily focused on puerarin in its dried roots. In this study, we investigated the potential effects and mechanisms of fresh P. lobata root-derived exosome-like nanovesicles (P-ELNs) for mitigating alcoholic intoxication, promoting alcohol metabolism effects and protecting the liver in C57BL/6J mice.

Methods

We isolated P-ELNs from fresh P. lobata root using differential centrifugation and characterized them via transmission electron microscopy, nanoscale particle sizing, ζ potential analysis, and biochemical assays. In Acute Alcoholism (AAI) mice pre-treated with P-ELNs, we evaluated their effects on the timing and duration of the loss of the righting reflex (LORR), liver alcohol metabolism enzymes activity, liver and serum alcohol content, and ferroptosis-related markers.

Results

P-ELNs, enriched in proteins, lipids, and small RNAs, exhibited an ideal size (150.7 ± 82.8 nm) and negative surface charge (-31 mV). Pre-treatment with 10 mg/(kg.bw) P-ELNs in both male and female mice significantly prolonged ebriety time, shortened sobriety time, enhanced acetaldehyde dehydrogenase (ALDH) activity while concurrently inhibited alcohol dehydrogenase (ADH) activity, and reduced alcohol content in the liver and serum. Notably, P-ELNs demonstrated more efficacy compared to P-ELNs supernatant fluid (abundant puerarin content), suggesting alternative active components beyond puerarin. Additionally, P-ELNs prevented ferroptosis by inhibiting the reduction of glutathione peroxidase 4 (GPX4) and reduced glutathione (GSH), and suppressing acyl-CoA synthetase long-chain family member 4 (ACSL4) elevation, thereby mitigating pathological liver lipid accumulation.

Conclusion

P-ELNs exhibit distinct exosomal characteristics and effectively alleviate alcoholic intoxication, improve alcohol metabolism, suppress ferroptosis, and protect the liver from alcoholic injury. Consequently, P-ELNs hold promise as a therapeutic agent for detoxification, sobriety promotion, and prevention of alcoholic liver injury.

ANK3 rs10994336 and ZNF804A rs7597593 polymorphisms: genetic interaction for emotional and behavioral symptoms of alcohol withdrawal syndrome

OBJECTIVE

Alcohol withdrawal syndrome (AWS) is a complex condition associated with alcohol use disorder (AUD), characterized by significant variations in symptom severity among patients. The psychological and emotional symptoms accompanying AWS significantly contribute to withdrawal distress and relapse risk. Despite the importance of neural adaptation processes in AWS, limited genetic investigations have been conducted. This study primarily focuses on exploring the single and interaction effects of single-nucleotide polymorphisms in the ANK3 and ZNF804A genes on anxiety and aggression severity manifested in AWS. By examining genetic associations with withdrawal-related psychopathology, we ultimately aim to advance understanding the genetic underpinnings that modulate AWS severity.

METHODS

The study involved 449 male patients diagnosed with alcohol use disorder. The Self-Rating Anxiety Scale (SAS) and Buss-Perry Aggression Questionnaire (BPAQ) were used to assess emotional and behavioral symptoms related to AWS. Genomic DNA was extracted from peripheral blood, and genotyping was performed using PCR.

RESULTS

Single-gene analysis revealed that naturally occurring allelic variants in ANK3 rs10994336 (CC homozygous vs. T allele carriers) were associated with mood and behavioral symptoms related to AWS. Furthermore, the interaction between ANK3 and ZNF804A was significantly associated with the severity of psychiatric symptoms related to AWS, as indicated by MANOVA. Two-way ANOVA further demonstrated a significant interaction effect between ANK3 rs10994336 and ZNF804A rs7597593 on anxiety, physical aggression, verbal aggression, anger, and hostility. Hierarchical regression analyses confirmed these findings. Additionally, simple effects analysis and multiple comparisons revealed that carriers of the ANK3 rs10994336 T allele experienced more severe AWS, while the ZNF804A rs7597593 T allele appeared to provide protection against the risk associated with the ANK3 rs10994336 mutation.

CONCLUSION

This study highlights the gene-gene interaction between ANK3 and ZNF804A, which plays a crucial role in modulating emotional and behavioral symptoms related to AWS. The ANK3 rs10994336 T allele is identified as a risk allele, while the ZNF804A rs7597593 T allele offers protection against the risk associated with the ANK3 rs10994336 mutation. These findings provide initial support for gene-gene interactions as an explanation for psychiatric risk, offering valuable insights into the pathophysiological mechanisms involved in AWS.

Forskolin reverses the O-GlcNAcylation dependent decrease in GABAAR current amplitude at hippocampal synapses possibly at a neurosteroid site on GABAARs

GABAergic transmission is influenced by post-translational modifications, like phosphorylation, impacting channel conductance, allosteric modulator sensitivity, and membrane trafficking. O-GlcNAcylation is a post-translational modification involving the O-linked attachment of β-N-acetylglucosamine on serine/threonine residues. Previously we reported an acute increase in O-GlcNAcylation elicits a long-term depression of evoked GABAAR inhibitory post synaptic currents (eIPSCs) onto hippocampal principal cells. Importantly, O-GlcNAcylation and phosphorylation can co-occur or compete for the same residue; whether they interact in modulating GABAergic IPSCs is unknown. We tested this by recording IPSCs from hippocampal principal cells and pharmacologically increased O-GlcNAcylation, before or after increasing serine phosphorylation using the adenylate cyclase activator, forskolin. Although forskolin had no significant effect on baseline eIPSC amplitude, we found that a prior increase in O-GlcNAcylation unmasks a forskolin-dependent increase in eIPSC amplitude, reversing the O-GlcNAc-induced eIPSC depression. Inhibition of adenylate cyclase or protein kinase A did not prevent the potentiating effect of forskolin, indicating serine phosphorylation is not the mechanism. Surprisingly, increasing O-GlcNAcylation also unmasked a potentiating effect of the neurosteroids 5α-pregnane-3α,21-diol-20-one (THDOC) and progesterone on eIPSC amplitude, mimicking forskolin. Our findings show under conditions of heightened O-GlcNAcylation, the neurosteroid site on synaptic GABAARs is accessible to agonists, permitting strengthening of synaptic inhibition.

Hovenia dulcis: a Chinese medicine that plays an essential role in alcohol-associated liver disease

Globally, alcohol-associated liver disease (ALD) has become an increased burden for society. Disulfirams, Benzodiazepines (BZDs), and corticosteroids are commonly used to treat ALD. However, the occurrence of side effects such as hepatotoxicity and dependence, impedes the achievement of desirable and optimal therapeutic efficacy. Therefore, there is an urgent need for more effective and safer treatments. Hovenia dulcis is an herbal medicine promoting alcohol removal clearance, lipid-lowering, anti-inflammatory, and hepatoprotective properties. Hovenia dulcis has a variety of chemical components such as dihydromyricetin, quercetin and beta-sitosterol, which can affect ALD through multiple pathways, including ethanol metabolism, immune response, hepatic fibrosis, oxidative stress, autophagy, lipid metabolism, and intestinal barrier, suggesting its promising role in the treatment of ALD. Thus, this work aims to comprehensively review the chemical composition of Hovenia dulcis and the molecular mechanisms involved in the process of ALD treatment.

Multi-modal neuroimaging reveals differences in alcohol-cue reactivity but not neurometabolite concentrations in adolescents who drink alcohol

BACKGROUND

The objective of this multi-modal neuroimaging study was to identify neuroscience-informed treatment targets for adolescent alcohol use disorder (AUD) by examining potential neural alterations associated with adolescent alcohol use.

METHODS

Adolescents (ages 17-19) who heavily used (n=49) or did not use alcohol (n=22) were recruited for a multi-modal neuroimaging protocol, including proton magnetic resonance spectroscopy within the dorsal anterior cingulate cortex (dACC) and an fMRI alcohol cue-reactivity task. The alcohol cue-reactivity task was analyzed across 11 a priori regions-of-interest (ROI), including the dACC, and in an exploratory whole-brain approach. Correlations were run between neurometabolite levels and alcohol cue-reactivity in the dACC.

RESULTS

There were no significant group differences in absolute neurometabolite concentrations. Compared to the control group, the alcohol-using group exhibited heightened alcohol cue reactivity in the left amygdala ROI (p=0.04). The whole-brain approach identified higher alcohol cue reactivity in the alcohol-using group compared to controls in the amygdala and occipital regions, and lower reactivity in the parietal lobe. Whole-brain sex effects were noted, with females displaying higher reactivity regardless of group. No significant correlations were found between neurometabolite levels and alcohol cue-reactivity in the dACC.

CONCLUSIONS

The null neurometabolic findings may be due to age, relatively low severity of alcohol use, and non-treatment-seeking status of the participants. Females showed overall higher reactivity to alcohol cues, indicating a sex effect regardless of alcohol use history. Higher amygdala reactivity in alcohol-using adolescents suggests that emotional processing related to alcohol cues may be a useful target for future adolescent AUD interventions.

A retrospective clinical practice study comparing the usefulness of dual-orexin receptor antagonists and a melatonin receptor agonist in patients switching from long-term benzodiazepine receptor agonists

STUDY OBJECTIVES

Although novel hypnotics have recently emerged, there are currently no data comparing the clinical potency of benzodiazepine receptor agonists (BZRAs) and novel hypnotics, or the effectiveness of different methods of switching between them. This study examined how novel hypnotics might help reduce BZRA use in real-world practice.

METHODS

289 patients with psychiatric disorders who took BZRAs for over 1 year before switching to either of 2 dual-orexin receptor antagonists (DORAs; suvorexant [SUV] or lemborexant [LEM]) or a melatonin receptor agonist (ramelteon [RMT]) were enrolled. We collected data on BZRAs at baseline and 3 months after commencement of SUV/LEM/RMT.

RESULTS

Significant reductions in BZRAs were observed for all 3 agents: -4.10, -2.80, and -1.65 mg in diazepam-equivalent doses in the SUV, LEM, and RMT groups, respectively. Dose reduction was significantly greater in the DORA than the RMT group (F = 15.053, P < .001). Within the DORA group, dose reduction was significantly greater in patients taking SUV than those taking LEM (F = 4.337, P = .043). The switching success rate did not differ among the switching methods for any of the hypnotics.

CONCLUSIONS

The reduction rate of BZRAs achieved by the switch fell into their equivalent-potency range estimated from clinical trials. The results suggest that DORAs can replace approximately 1 tablet of a BZRA. The difference in dose reduction between DORAs and RMT reflected the greater sleeping potency of the DORAs, whereas that between SUV and LEM might have reflected patient backgrounds: patients taking LEM may have been more strongly dependent on BZRAs.

CITATION

Tachibana M, Kanahara N, Oda Y, Hasegawa T, Kimura A, Iyo M. A retrospective clinical practice study comparing the usefulness of dual-orexin receptor antagonists and a melatonin receptor agonist in patients switching from long-term benzodiazepine receptor agonists. J Clin Sleep Med. 2024;20(4):603-613.

Examining the relationship between the oral microbiome, alcohol intake and alcohol-comorbid neuropsychological disorders: protocol for a scoping review

INTRODUCTION

Heavy alcohol use and alcohol use disorder (AUD) continues to rise as a public health problem and increases the risk for disease. Elevated rates of anxiety, depression, sleep disruption and stress are associated with alcohol use. Symptoms may progress to diagnosed neurophysiological conditions and increase risk for relapse if abstinence is attempted. Research on mechanisms connecting the gastrointestinal microbiome to neuropsychological disorders through the gut-brain axis is well-established. Less is known how the oral microbiome and oral microbial-associated biomarkers may signal to the brain. Therefore, a synthesis of research studying relationships between alcohol intake, alcohol-associated neurophysiological symptoms and the oral microbiome is needed to understand the state of the current science. In this paper, we outline our protocol to collect, evaluate and synthesise research focused on associations between alcohol intake and AUD-related neuropsychological disorders with the oral microbiome.

METHODS AND ANALYSIS

The search strategy was developed and will be executed in collaboration with a medical research librarian. Studies will be screened by two independent investigators according to the aim of the scoping review, along with the outlined exclusion and inclusion criteria. After screening, data will be extracted and synthesised from the included papers according to predefined demographic, clinical and microbiome methodology metrics.

ETHICS AND DISSEMINATION

A scoping review of primary sources is needed to synthesise the data on relationships between alcohol use, neuropsychological conditions associated with AUD and the oral microbiome. The proposed scoping review is based on the data from publicly available databases and does not require ethical approval. We expect the results of this synthesis will identify gaps in the growing literature and highlight potential mechanisms linking the oral-brain axis to addiction and other associated neuropsychological conditions. The study findings and results will be disseminated through journals and conferences related to psychology, neuroscience, dentistry and the microbiome.

Forskolin reverses the O-GlcNAcylation dependent decrease in GABAAR current amplitude at hippocampal synapses possibly through a neurosteroid site on GABAARs

GABAergic transmission is influenced by post-translational modifications, like phosphorylation, impacting channel conductance, allosteric modulator sensitivity, and membrane trafficking. O-GlcNAcylation is a post-translational modification involving the O-linked attachment of β-N-acetylglucosamine on serine/threonine residues. Previously we reported an acute increase in O-GlcNAcylation elicits a long-term depression of evoked GABAAR inhibitory post synaptic currents (eIPSCs) onto hippocampal principal cells. Importantly O-GlcNAcylation and phosphorylation can co-occur or compete for the same residue; whether they interact in modulating GABAergic IPSCs is unknown. We tested this by recording IPSCs from hippocampal principal cells and pharmacologically increased O-GlcNAcylation, before or after increasing serine phosphorylation using the adenylate cyclase activator, forskolin. Although forskolin had no significant effect on baseline eIPSC amplitude, we found that a prior increase in O-GlcNAcylation unmasks a forskolin-dependent increase in eIPSC amplitude, reversing the O-GlcNAc-induced eIPSC depression. Inhibition of adenylate cyclase or protein kinase A did not prevent the potentiating effect of forskolin, indicating serine phosphorylation is not the mechanism. Surprisingly, increasing O-GlcNAcylation also unmasked a potentiating effect of the neurosteroids 5α-pregnane-3α,21-diol-20-one (THDOC) and progesterone on eIPSC amplitude, mimicking forskolin. Our findings show under conditions of heightened O-GlcNAcylation, the neurosteroid site on synaptic GABAARs is accessible to agonists, permitting strengthening of synaptic inhibition.

Alcohol metabolism in alcohol use disorder: a potential therapeutic target

Ethanol metabolism plays an essential role in how the body perceives and experiences alcohol consumption, and evidence suggests that modulation of ethanol metabolism can alter the risk for alcohol use disorder (AUD). In this review, we explore how ethanol metabolism, mainly via alcohol dehydrogenase and aldehyde dehydrogenase 2 (ALDH2), contributes to drinking behaviors by integrating preclinical and clinical findings. We discuss how alcohol dehydrogenase and ALDH2 polymorphisms change the risk for AUD, and whether we can harness that knowledge to design interventions for AUD that alter ethanol metabolism. We detail the use of disulfiram, RNAi strategies, and kudzu/isoflavones to inhibit ALDH2 and increase acetaldehyde, ideally leading to decreases in drinking behavior. In addition, we cover recent preclinical evidence suggesting that strategies other than increasing acetaldehyde-mediated aversion can decrease ethanol consumption, providing other potential metabolism-centric therapeutic targets. However, modulating ethanol metabolism has inherent risks, and we point out some of the key areas in which more data are needed to mitigate these potential adverse effects. Finally, we present our opinions on the future of treating AUD by the modulation of ethanol metabolism.

A paradoxical switch: the implications of excitatory GABAergic signaling in neurological disorders

Gamma-aminobutyric acid (GABA) is the primary inhibitory neurotransmitter in the central nervous system. In the mature brain, inhibitory GABAergic signaling is critical in maintaining neuronal homeostasis and vital human behaviors such as cognition, emotion, and motivation. While classically known to inhibit neuronal function under physiological conditions, previous research indicates a paradoxical switch from inhibitory to excitatory GABAergic signaling that is implicated in several neurological disorders. Various mechanisms have been proposed to contribute to the excitatory switch such as chloride ion dyshomeostasis, alterations in inhibitory receptor expression, and modifications in GABAergic synaptic plasticity. Of note, the hypothesized mechanisms underlying excitatory GABAergic signaling are highlighted in a number of neurodevelopmental, substance use, stress, and neurodegenerative disorders. Herein, we present an updated review discussing the presence of excitatory GABAergic signaling in various neurological disorders, and their potential contributions towards disease pathology.

Treating posttraumatic stress disorder and alcohol use disorder comorbidity: Current pharmacological therapies and the future of MDMA-integrated psychotherapy

Posttraumatic stress disorder (PTSD) and alcohol use disorder (AUD) frequently co-occur in patients who have experienced trauma. This comorbidity leads to a vicious cycle where PTSD symptoms beget heavy drinking and vice versa. There are no FDA-approved medications to treat PTSD-AUD; therefore, individuals suffering from this comorbidity are treated with medication approved to treat the disorders separately or with off-label pharmacological interventions. However, these medications are limited in their efficacy for treating PTSD-AUD comorbidity. Emerging research on the nonclassical psychedelic drug 3,4-methylenedioxymethamphetamine (MDMA) suggests that it may be an effective drug used in conjunction with psychotherapy. The following reviews the current research for clinical pharmacotherapies, as well as MDMA-integrative psychotherapy as they pertain to PTSD and AUD in isolation and co-occurrence. Future directions for the role of psychedelic-integrative therapy for the treatment of this comorbidity are discussed.

GABAergic signaling in alcohol use disorder and withdrawal: pathological involvement and therapeutic potential

Alcohol is one of the most widely used substances. Alcohol use accounts for 5.1% of the global disease burden, contributes substantially to societal and economic costs, and leads to approximately 3 million global deaths yearly. Alcohol use disorder (AUD) includes various drinking behavior patterns that lead to short-term or long-lasting effects on health. Ethanol, the main psychoactive molecule acting in alcoholic beverages, directly impacts the GABAergic system, contributing to GABAergic dysregulations that vary depending on the intensity and duration of alcohol consumption. A small number of interventions have been developed that target the GABAergic system, but there are promising future therapeutic avenues to explore. This review provides an overview of the impact of alcohol on the GABAergic system, the current interventions available for AUD that target the GABAergic system, and the novel interventions being explored that in the future could be included among first-line therapies for the treatment of AUD.

N-acetylcysteine does not alter neurometabolite levels in non-treatment seeking adolescents who use alcohol heavily: A preliminary randomized clinical trial

Current treatments for adolescent alcohol use disorder (AUD) are mainly psychosocial and limited in their efficacy. As such, pharmacotherapies are being investigated as potential adjunctive treatments to bolster treatment outcomes. N-acetylcysteine is a promising candidate pharmacotherapy for adolescent AUD because of its tolerability and demonstrated ability to modulate glutamatergic, GABAergic, and glutathione systems. The primary objective of this double-blind, placebo-controlled, within-subjects crossover preliminary investigation was to measure potential changes within glutamate + glutamine (Glx), GABA, and glutathione levels in the dorsal anterior cingulate cortex (dACC) using proton magnetic resonance spectroscopy during 10-days of N-acetylcysteine (1200 mg twice daily) compared to 10-days of placebo in non-treatment seeking adolescents who use alcohol heavily (N = 31; 55% female). Medication adherence was confirmed via video. Effects on alcohol use were measured using Timeline Follow-Back as an exploratory aim. Linear mixed effects models controlling for baseline metabolite levels, brain tissue composition, alcohol use, cannabis use, and medication adherence found no significant differences in Glx, GABA, or glutathione levels in the dACC after N-acetylcysteine compared to placebo. There were also no measurable effects on alcohol use; however, this finding was underpowered. Findings were consistent in the subsample of participants who met criteria for AUD (n = 19). The preliminary null findings in brain metabolite levels may be due to the young age of participants, relatively low severity of alcohol use, and non-treatment seeking status of the population investigated. Future studies can use these findings to conduct larger, well-powered studies within adolescents with AUD.

Chemical Constituents from the Fruits of Amomum kravanh and Their Role in Activating Alcohol Dehydrogenase

Alcoholism is a worldwide health problem, and diseases caused by alcoholism are killing people every year. Amomum kravanh is a traditional Chinese medicine used to relieve hangovers. However, whether its bioactive components improve alcohol metabolism is not clear. In this study, ten new (amomumols A-J, 1-10) and thirty-five known (11-45) compounds were isolated from the fruits of Amomum kravanh by an activity-guided separation. Ten novel compounds were identified as four sesquiterpenoids (1-4), three monoterpene derivatives (5-7), two neolignans (8, 9), and a novel norsesquiterpenoid (10) with a new C₁₄ nor-bisabolane skeleton. Their structures were determined by the comprehensive analysis of high-resolution electrospray ionization mass spectrometry (HRESIMS), nuclear magnetic resonance (NMR), and electronic circular dichroism (ECD) calculation. The effects of all isolated compounds on the activity of alcohol dehydrogenase were evaluated in vitro, and it was found that eight compounds (11, 12, 15, 18, 26, and 36-38) exhibited significant activation effects on the alcohol dehydrogenase at 50 μM.

Trajectories of change in subclinical anxiety and alcohol use during alcohol treatment: A parallel process growth model

BACKGROUND

Anxiety is implicated in the course and prognosis of alcohol use disorder (AUD); however, it is unclear how current AUD treatments affect the joint trajectories of anxiety and alcohol use. We used data from the Combined Pharmacotherapies and Behavioral Interventions for Alcohol Dependence (COMBINE) study to examine the longitudinal relationship between subclinical anxiety symptoms and alcohol use during and following AUD treatment in adults with AUD and no comorbid anxiety disorders.

METHODS

Univariate and parallel process growth models using five waves of COMBINE study data were analyzed from 865 adults randomized to medication (n = 429) or medication plus psychotherapy (n = 436). Weekly drinking quantity and average weekly anxiety symptoms were measured at baseline, mid-treatment, end-of-treatment, and three follow-up periods.

RESULTS

Significant positive associations of anxiety symptoms and drinking were found at mid-treatment and over time. Temporal associations revealed that higher mid-treatment anxiety predicted decreases in drinking over time. Baseline anxiety and drinking predicted mid-treatment anxiety and drinking. Only baseline anxiety predicted increases in drinking over time. Group differences revealed mid-treatment drinking predicted decreases in anxiety over time in the medication group.

CONCLUSIONS

Findings demonstrate the influence of subclinical anxiety on alcohol use during and up to one year after AUD treatment. Baseline anxiety symptoms may influence drinking behavior over the course of treatment. Findings suggest that greater attention to negative affect in AUD treatment is warranted even for those individuals who do have a comorbid anxiety disorder.

Gender-specific differences in comorbidities, in-hospital complications and outcomes in emergency patients with ethanol intoxication with and without multisubstance use

AIMS OF THE STUDY

To analyse gender-specific differences in comorbidities, multisubstance abuse, in-hospital complications, intensive care unit transfers and referrals to psychiatric wards of emergency department patients with ethanol intoxication. Several lines of evidence suggest an influence of gender differences on diagnostic and therapeutic approaches to various diseases.

METHODS

Over a period of 7 years, all patients with signs or symptoms of ethanol intoxication and a positive blood ethanol test admitted for the first time to the emergency department of a Swiss regional tertiary referral hospital were prospectively enrolled. Patients were categorised into two subgroups: patients without additional drug use were considered ethanol-only cases, whereas patients who had also ingested other substances (as determined from bystanders, physicians and urine drug screening) were considered multisubstance cases. A retrospective analysis of this database evaluated gender-specific differences in comorbidities, multisubstance abuse, in-hospital complications, intensive care unit transfers and referrals to psychiatric wards within these two subgroups. Statistical analysis included Fisher's exact test for categorical data and Wilcoxon rank sum test for continuous data.

RESULTS

Of 409 enrolled patients, 236 cases were ethanol-only and 173 were multisubstance cases. The three most common comorbidities in multisubstance patients showed significant gender differences: psychiatric disorders (43% males vs 61% females; p = 0.022), chronic ethanol abuse (55% males vs 32% females; p = 0.002) and drug addiction (44% males vs 17% females; p = 0.001). Gender differences were also found for the most frequently co-ingested substances: benzodiazepines (35% males vs 43% females; p = 0.014), cannabis (45% males vs 24% females; p = 0.006) and cocaine (24% males vs 6% females; p = 0.001). Male and female ethanol-only patients were transferred to the intensive care unit in 8% of cases. In multisubstance cases, 32% of male and 43% of female patients were transferred to the intensive care unit (no significant gender difference). The psychiatric ward referral rate in male (30%) and female (48%) patients with multisubstance abuse was significantly different (p = 0.028). No significant gender difference in psychiatric ward referral rates was observed for ethanol-only patients (12% males, 17% females).

CONCLUSION

Among emergency department patients admitted with ethanol intoxication, gender differences in comorbidities, substance use and psychiatric ward referrals were highly significant among patients who presented with multisubstance abuse. Rates of intensive care unit transfer for patients with ethanol intoxication are substantial for both genders, reflecting relevant disease burden and resource demand, as well as the need for further preventive efforts.

Neurobiological mechanisms and related clinical treatment of addiction: a review

Drug addiction or substance use disorder (SUD), has been conceptualized as a three-stage (i.e. binge/intoxication, withdrawal/negative affect, and preoccupation/anticipation/craving) recurring cycle that involves complex changes in neuroplasticity, reward, motivation, desire, stress, memory, and cognitive control, and other related brain regions and brain circuits. Neuroimaging approaches, including magnetic resonance imaging, have been key to mapping neurobiological changes correlated to complex brain regions of SUD. In this review, we highlight the neurobiological mechanisms of these three stages of addiction. The abnormal activity of the ventral tegmental, nucleus accumbens, and caudate nucleus in the binge/intoxication stage involve the reward circuit of the midbrain limbic system. The changes in the orbitofrontal cortex, dorsolateral prefrontal cortex, amygdala, and hypothalamus emotional system in the withdrawal/negative affect stage involve increases in negative emotional states, dysphoric-like effects, and stress-like responses. The dysregulation of the insula and prefrontal lobes is associated with craving in the anticipation stage. Then, we review the present treatments of SUD based on these neuroimaging findings. Finally, we conclude that SUD is a chronically relapsing disorder with complex neurobiological mechanisms and multimodal stages, of which the craving stage with high relapse rate may be the key element in treatment efficacy of SUD. Precise interventions targeting different stages of SUD and characteristics of individuals might serve as a potential therapeutic strategy for SUD.

Illicit Drug Use and Endoscopy: When Do We Say No?

BACKGROUND

Illicit drug use (IDU) is often encountered in patients undergoing elective ambulatory surgical procedures such as endoscopy. Given the variety of systemic effects of these drugs, sedation and anesthetics are believed to increase the risk of cardiopulmonary complications during procedures. Procedural cancelations are common, regardless of the drug type, recency of use, and total dosage consumed. There is a lack of institutional and society recommendations regarding the optimal approach to performing outpatient endoscopy on patients with IDU.

AIM

To review the literature for current recommendations regarding the optimal management of outpatient elective endoscopic procedures in patients with IDU. Secondary aim is to provide guidance for clinicians who encounter IDU in endoscopic practice.

METHODS

Systematic review of PubMed, CINAHL, Embase, and Google Scholar for articles presenting data on outcomes of elective procedures in patients using illicit drugs.

RESULTS

There are no clinically relevant differences in periprocedural complications or mortality in cannabis users compared to non-users. Endoscopy in patients with remote cocaine use was also found to have similar outcomes to recent use.

CONCLUSIONS

Canceling endoscopic procedures in patients with recent IDU without consideration of the type of drug, dosage, and chronicity may lead to unnecessary delays in care and increased patient morbidity. Healthcare systems would benefit from additional guidelines for evaluating the patient with recent illicit drug use for acute intoxication and consider proceeding with procedures in the non-toxic population.

Neurosteroids (allopregnanolone) and alcohol use disorder: From mechanisms to potential pharmacotherapy

Alcohol Use Disorder (AUD) is a multifaceted relapsing disorder that is commonly comorbid with psychiatric disorders, including anxiety. Alcohol exposure produces a plethora of effects on neurobiology. Currently, therapeutic strategies are limited, and only a few treatments - disulfiram, acamprosate, and naltrexone - are available. Given the complexity of this disorder, there is a great need for the identification of novel targets to develop new pharmacotherapy. The GABAergic system, the primary inhibitory system in the brain, is one of the well-known targets for alcohol and is responsible for the anxiolytic effects of alcohol. Interestingly, GABAergic neurotransmission is fine-tuned by neuroactive steroids that exert a regulatory role on several endocrine systems involved in neuropsychiatric disorders including AUD. Mounting evidence indicates that alcohol alters the biosynthesis of neurosteroids, whereas acute alcohol increases and chronic alcohol decreases allopregnanolone levels. Our recent work highlighted that chronic alcohol-induced changes in neurosteroid levels are mediated by epigenetic modifications, e.g., DNA methylation, affecting key enzymes involved in neurosteroid biosynthesis. These changes were associated with changes in GABAA receptor subunit expression, suggesting an imbalance between excitatory and inhibitory signaling in AUD. This review will recapitulate the role of neurosteroids in the regulation of the neuroendocrine system, highlight their role in the observed allostatic load in AUD, and develop a framework from mechanisms to potential pharmacotherapy.

On the Role of Stimulus-Response Context in Inhibitory Control in Alcohol Use Disorder

The behavioral and neural dynamics of response inhibition deficits in alcohol use disorder (AUD) are still largely unclear, despite them possibly being key to the mechanistic understanding of the disorder. Our study investigated the effect of automatic vs. controlled processing during response inhibition in participants with mild-to-moderate AUD and matched healthy controls. For this, a Simon Nogo task was combined with EEG signal decomposition, multivariate pattern analysis (MVPA), and source localization methods. The final sample comprised n = 59 (32♂) AUD participants and n = 64 (28♂) control participants. Compared with the control group, AUD participants showed overall better response inhibition performance. Furthermore, the AUD group was less influenced by the modulatory effect of automatic vs. controlled processes during response inhibition (i.e., had a smaller Simon Nogo effect). The neurophysiological data revealed that the reduced Simon Nogo effect in the AUD group was associated with reduced activation differences between congruent and incongruent Nogo trials in the inferior and middle frontal gyrus. Notably, the drinking frequency (but not the number of AUD criteria we had used to distinguish groups) predicted the extent of the Simon Nogo effect. We suggest that the counterintuitive advantage of participants with mild-to-moderate AUD over those in the control group could be explained by the allostatic model of drinking effects.

Evaluation of the effect of alpha-tocopherol on anxiety and the neuroinflammatory process during alcohol withdrawal in a model of forced and chronic self-administration of liquid diet containing ethanol: Behavioral and neurochemical evidence

Alcoholism affects about 2 billion people worldwide. Withdrawal causes a neuroinflammatory response that increases anxiety. α-tocopherol is the most important antioxidant that has its in vivo action currently known. Therefore, this study aimed to evaluate the effect of α-tocopherol on the neuroinflammatory process in brain regions involved in anxiety and its anxiolytic potential during alcohol withdrawal. For this, male Wistar rats were divided into four groups and submitted to a procedure of forced and chronic self-administration of liquid diet containing 6% and 8% ethanol for 15 days, followed by abrupt interruption of treatment. Animals in the control group received the liquid diet without ethanol. Twenty-four or 48 h after ethanol discontinuation, and 30 min after the last administration of α-tocopherol or saline, animals were evaluated in the elevated plus maze, light/dark box, and open field tests. At the end of the tests, each experimental group underwent brain tissue collection for analysis of cytokine levels. The results showed that: alcohol induces the neuroinflammatory process and anxiety; the stress generated by withdrawal can induce oxidative stress, which alters the production of inflammatory cytokines in the amygdaloid nuclei (AN) and medial hypothalamic nucleus (mHN); α-tocopherol exhibited anxiolytic and anti-inflammatory activity, attenuating the anxious behavior of abstinent animals and reducing neuroinflammation in AN and mHN; and the intensity of the anxiolytic and anti-inflammatory effect of α-tocopherol is dose-dependent. These results identify α-tocopherol as a potential therapeutic target supporting the fight against relapse during alcohol withdrawal.

Classic psychedelics and alcohol use disorders: A systematic review of human and animal studies

Classic psychedelics refer to substances such as lysergic acid diethylamide (LSD), psilocybin, ayahuasca, and mescaline, which induce altered states of consciousness by acting mainly on 5-HT2A receptors. Recently, the interest of psychedelics as pharmacological treatment for psychiatric disorders has increased significantly, including their use on problematic use of alcohol. This systematic review is aimed to analyse the last two decades of studies examining the relationship between classic psychedelics and alcohol consumption. We searched PubMed and PsycInfo for human and preclinical studies published between January 2000 to December 2021. The search identified 639 publications. After selection, 27 studies were included. Human studies (n = 20) generally show promising data and seem to indicate that classic psychedelics could help reduce alcohol consumption. Nevertheless, some of these studies present methodological concerns such as low number of participants, lack of control group or difficulty in determining the effect of classic psychedelics in isolation. On the other hand, preclinical studies (n = 7) investigating the effect of these compounds on voluntary alcohol consumption are scarce and show some conflicting data. Among these compounds, psilocybin seems to show the most consistent data indicating that this compound could be a potential candidate to treat alcohol use disorders. In the absence of understanding the biological and/or psychological mechanisms, more studies including methodological quality parameters are needed to finally determine the effects of classic psychedelics on alcohol consumption.

Evaluation of pathways to the C-glycosyl isoflavone puerarin in roots of kudzu (Pueraria montana lobata)

Kudzu (Pueraria montana lobata) is used as a traditional medicine in China and Southeast Asia but is a noxious weed in the Southeastern United States. It produces both O- and C-glycosylated isoflavones, with puerarin (C-glucosyl daidzein) as an important bioactive compound. Currently, the stage of the isoflavone pathway at which the C-glycosyl unit is added remains unclear, with a recent report of direct C-glycosylation of daidzein contradicting earlier labeling studies supporting C-glycosylation at the level of chalcone. We have employed comparative mRNA sequencing of the roots from two Pueraria species, one of which produces puerarin (field collected P. montana lobata) and one of which does not (commercial Pueraria phaseoloides), to identify candidate uridine diphosphate glycosyltransferase (UGT) enzymes involved in puerarin biosynthesis. Expression of recombinant UGTs in Escherichia coli and candidate C-glycosyltransferases in Medicago truncatula were used to explore substrate specificities, and gene silencing of UGT and key isoflavone biosynthetic genes in kudzu hairy roots employed to test hypotheses concerning the substrate(s) for C-glycosylation. Our results confirm UGT71T5 as a C-glycosyltransferase of isoflavone biosynthesis in kudzu. Enzymatic, isotope labeling, and genetic analyses suggest that puerarin arises both from the direct action of UGT71T5 on daidzein and via a second route in which the C-glycosidic linkage is introduced to the chalcone isoliquiritigenin.

Subregional Differences in Alcohol Modulation of Central Amygdala Neurocircuitry

Alcohol use disorder is a highly significant medical condition characterized by an impaired ability to stop or control alcohol use, compulsive alcohol seeking behavior, and withdrawal symptoms in the absence of alcohol. Understanding how alcohol modulates neurocircuitry critical for long term and binge-like alcohol use, such as the central amygdala (CeA), may lead to the development of novel therapeutic strategies to treat alcohol use disorder. In clinical studies, reduction in the volume of the amygdala has been linked with susceptibility to relapse to alcohol use. Preclinical studies have shown the involvement of the CeA in the effects of alcohol use, with lesions of the amygdala showing a reduction in alcohol drinking, and manipulations of cells in the CeA altering alcohol drinking. A great deal of work has shown that acute alcohol, as well as chronic alcohol exposure via intake or dependence models, alters glutamatergic and GABAergic transmission in the CeA. The CeA, however, contains heterogeneous cell populations and distinct subregional differences in neurocircuit architecture which may influence the mechanism by which alcohol modulates CeA function overall. The current review aimed to parse out the differences in alcohol effects on the medial and lateral subregions of the CeA, and what role neuroinflammatory cells and markers, the endocannabinoid system, and the most commonly studied neuropeptide systems play in mediating these effects. A better understanding of alcohol effects on CeA subregional cell type and neurocircuit function may lead to development of more selective pharmacological interventions for alcohol use disorder.

Relapse prevention for alcohol use disorders: combined acamprosate and cue exposure therapy as aftercare

AIMS

Many patients with alcohol use disorders are challenged by cravings leading to repeated relapses. Both cue exposure therapy (CET) and acamprosate target alcohol cravings and are often combined (CET + acamprosate). The main aim of this study was to investigate whether aftercare treatment consisting of CET combined with acamprosate is equivalent to (A) CET as monotherapy, (B) aftercare as usual (AAU) as monotherapy or (C) AAU combined with acamprosate.

METHODS

Patients were randomized to receive either CET with urge-specific coping skills (USCS) as aftercare or AAU. Acamprosate prescription data were extracted from patient case records. Alcohol consumption, cravings, and USCS were assessed at pre-aftercare, post-aftercare, and 6-month follow-up.

RESULTS

Overall, patients increased their alcohol consumption during and following aftercare treatment, thereby relapsing despite any treatment. However, CET + acamprosate achieved greater abstinence compared to AAU + acamprosate at follow-up (p=.047). CET + acamprosate also reduced number of drinking days (p=.020) and number of days with excessive drinking (p=.020) at post-aftercare, when compared to AAU monotherapy. CET monotherapy increased sensible drinking at post-aftercare compared to AAU monotherapy (p=.045) and AAU + acamprosate (p=.047). Only CET monotherapy showed improvement in cravings, when compared to AAU at follow-up (mean urge level: p=.032; peak urge level: p=.014).

CONCLUSION

The study showed that CET both as monotherapy and combined with acamprosate was superior to AAU monotherapy and AAU + acamprosate in reducing alcohol consumption. Only CET + acamprosate was capable of reducing alcohol consumption in the longer term, indicating that anti-craving medication may not impede CET from exerting an effect on alcohol consumption. Trial registration: ClinicalTrials.gov ID: NCT02298751 (24/11-2014).

The effect of neuroimmune modulation on subjective response to alcohol in the natural environment

BACKGROUND

Despite the promising implications for novel immune therapeutics, few clinical trials have tested these therapies to date. An understanding of how immune pharmacotherapies influence complex alcohol use disorder (AUD) profiles, including subjective response to alcohol, is very limited. Initial findings show that ibudilast, a neuroimmune modulator, reduces rates of heavy drinking and measures of alcohol craving.

METHODS

This study is a secondary analysis of a 2-week clinical trial of ibudilast that enrolled a nontreatment-seeking sample with AUD. Eligible participants (N = 52) were randomized to receive ibudilast or matched placebo and completed daily diary assessments (DDAs) during the 2-week period. Each morning, participants reported on their mood and craving levels both before and during the previous day's drinking episode, as well as stimulation and sedation levels during the previous day's drinking episode. Multilevel models were used to compare the effects of ibudilast and placebo on subjective alcohol response. Exploratory analyses tested whether ibudilast moderated the relationship between daily stimulation/sedation and alcohol intake and whether withdrawal-related dysphoria moderated ibudilast's effects on subjective response.

RESULTS

Ibudilast did not significantly alter mean levels of stimulation or sedation (p's > 0.05). It did, however, moderate the effect of daily stimulation on drinking (p = 0.045). Ibudilast attenuated alcohol-induced increases in craving compared with placebo (p = 0.047), but not other subjective response measures. Ibudilast significantly tempered daily alcohol-induced changes in urge to drink and positive mood only among individuals without withdrawal-related dysphoria.

CONCLUSIONS

Ibudilast's effects on subjective alcohol responses appear to be nuanced and perhaps most salient for individuals drinking for positive reinforcement as distinguished from those who drink to feel normal. Consistent with previous findings, reductions in alcohol craving may represent a primary mechanism of ibudilast's effects on drinking. The ecologically valid nature of DDAs provide a clinically useful window into how individuals experience alcohol's effects while taking ibudilast.

Randomised trial of intravenous thiamine and/or magnesium sulphate administration on erythrocyte transketolase activity, lactate concentrations and alcohol withdrawal scores

Alcohol withdrawal syndrome (AWS) occurs in 2% of patients admitted to U.K. hospitals. Routine treatment includes thiamine and benzodiazepines. Laboratory studies indicate that thiamine requires magnesium for optimal activity, however this has not translated into clinical practice. Patients experiencing AWS were randomized to three groups: (group 1) thiamine, (group 2) thiamine plus MgSO₄ or (group 3) MgSO₄. Pre- and 2-h post-treatment blood samples were taken. AWS severity was recorded using the Glasgow Modified Alcohol Withdrawal Score (GMAWS). The primary outcome measure was 15% change in erythrocyte transketolase activity (ETKA) in group 3. Secondary outcome measures were change in plasma lactate concentrations and time to GMAWS = 0. 127 patients were recruited, 115 patients were included in the intention-to-treat analysis. Pre-treatment, the majority of patients had normal or high erythrocyte thiamine diphosphate (TDP) concentrations (≥ 275–675/> 675 ng/gHb respectively) (99%), low serum magnesium concentrations (< 0.75 mmol/L) (59%), and high plasma lactate concentrations (> 2 mmol/L) (67%). Basal ETKA did not change significantly in groups 1, 2 or 3. Magnesium deficient patients (< 0.75 mmol/L) demonstrated less correlation between pre-treatment basal ETKA and TDP concentrations than normomagnesemic patients (R² = 0.053 and R² = 0.236). Median plasma lactate concentrations normalized (≤ 2.0 mmol/L) across all three groups (p < 0.001 for all groups), but not among magnesium deficient patients in group 1 (n = 22). The median time to achieve GMAWS = 0 for groups 1, 2 and 3 was 10, 5.5 and 6 h respectively (p < 0.001). No significant difference was found between groups for the primary endpoint of change in ETKA. Co-administration of thiamine and magnesium resulted in more consistent normalization of plasma lactate concentrations and reduced duration to achieve initial resolution of AWS symptoms.

ClinicalTrials.gov: NCT03466528.

Dihydromyricetin Protects Against Ethanol-Induced Toxicity in SH-SY5Y Cell Line: Role of GABAA Receptor

Toxicity induced by binge alcohol drinking, particularly in adolescent and young adults, is of major medical and social consequence. Recently, we reported that butyrate, a short chain fatty acid, can protect against ethanol (ETOH)-induced toxicity in an in vitro model. In this study, we sought to evaluate the potential effectiveness of dihydromyricetin (DHM), a natural bioactive flavonoid, alone or in combination with butyrate in the same model. Exposure of SH-SY5Y cells for 24 h to 500 mM ETOH resulted in approximately 40% reduction in cell viability, which was completely prevented by 0.1 μM DHM. Combinations of DHM and butyrate provided synergistic protection against alcohol toxicity. Whereas butyrate effect was shown to be mediated primarily through fatty acid receptor 3 activation, DHM protection appears to be mediated primarily via benzodiazepine receptor site of GABA_A receptor. This is based on the finding that DHM's effect could be completely prevented by pretreatment with flumazenil, a selective antagonist at this site, but not by bicuculline, a selective antagonist at the actual GABA_A receptor binding site. These findings suggest potential utility of DHM alone or in combination with butyrate against ETOH-induced toxicity.

Sex differences in GABAA receptor subunit transcript expression are mediated by genotype in subjects with alcohol-related cirrhosis of the liver

Male and female human subjects show contrasting propensities to misuse drugs of addiction, including alcohol. These differences lead to different psychological and neurological consequences, such as the likelihood of developing dependence. The pattern and extent of brain damage in alcohol-use disorder cases also varies with comorbid disease. To explore mechanisms that might underlie these outcomes, we used autopsy tissue to determine mRNA transcript expression in relation to genotype for two GABAA receptor subunit genes. We used quantitative Real-Time PCR to measure GABRA6 and GABRA2 mRNA concentrations in dorsolateral prefrontal and primary motor cortices of alcohol-use disorder subjects and controls of both sexes with and without liver disease who had been genotyped for these GABAA receptor subunit genes. Cirrhotic alcohol-use disorder cases had significantly higher expression of GABRA6 and GABRA2 transcripts than either controls or non-cirrhotic alcohol-use disorder cases. Differences were observed between sexes, genotypes and brain regions. We show that sex differences in subjects with GABRA6 and GABRA2 variants may contribute to differences in susceptibility to alcohol-use disorder and alcohol-induced cirrhosis.

Differences between cultured cortical neurons by trypsin and papain digestion

The objective of this study was to compare the efficiency of trypsin and papain in neuronal digestion and determine which enzyme is more efficient. Cortical tissues were obtained from Sprague-Dawley (SD) rats. According to the different digestive enzymes, the samples were divided into the trypsin group and the papain group. After being digested by each of the two enzymes, cortical neurons were collected from the samples. Then, the morphology of the cortical neurons was determined. Moreover, the cortical neurons were transfected with the negative control (NC) lentivirus. The transfection efficiency and morphology were determined and compared. Compared with the papain group, cortical neurons in the trypsin group were more in number, had larger cell size, had longer axonal length, and had fewer impurities. The transfection efficiency of the trypsin group (57.77%) was higher than that of the papain group (53.83%). The morphology of neurons that was displayed showed that the cell body of most neurons shrank and became smaller, and the axis mutation became shorter and less in the papain group 6 days after transfection with the NC lentivirus. Trypsin is more efficient in digesting neurons because the neurons digested by this enzyme are more in number, have a larger cell body, longer axons, and greater transfection efficiency.

Rewarding effect of ethanol-induced conditioned place preference in mice: Effect of the monoterpenoid linalool

Alcohol addiction is a chronic relapsing disease that is progressive and has severe detrimental health outcomes. The use of natural products has become popular for the treatment of side effects of drugs and substance abuse. Linalool is a monoterpenoid that exhibits several effects on the central nervous system. Linalool was identified to have beneficial effects on different mechanisms that are relevant in drug addiction or substance use disorder. The primary aim of the present study was to evaluate the therapeutic effect of linalool on the rewarding properties of alcohol in mice. Conditioned place preference (CPP) was established by intraperitoneal (i.p.) injection of ethanol (2 g/kg) during an 8-day conditioning trial. The effects of acamprosate and linalool on the rewarding properties of ethanol were tested in mice who received linalool (12.5, 25, and 50 mg/kg, i.p.) and acamprosate (300 mg/kg, i.p.) 30 min before each ethanol injection. CPP was extinguished by repeated testing, throughout which conditioned mice were administered daily linalool. Mice were lastly examined for reinstatement provoked by i.p. administration of single low-dose ethanol (0.4 g/kg, i.p.). Treatment with linalool reduced the acquisition and reinstatement, and precipitated the extinction of ethanol-induced CPP in mice. Acquisition and reinstatement of alcohol-induced CPP were significantly reduced by acamprosate, which also precipitated extinction. Ethanol alone and the combination with linalool or acamprosate did not alter locomotor activity. The results of this study suggest that linalool may have pharmacological effects for the treatment of alcohol addiction. In addition, further investigation is required to fully explore the benefits and possible adverse effects of linalool on alcohol addiction.

Missing a case of nitrous oxide toxicity

Nitrous oxide is a highly lipid-soluble molecule, which can produce euphoria and calming effects through noncompetitive antagonism of the N-methyl-D-aspartate (NMDA) glutamate receptor and agonism of the y-aminobutyric acid (GABA) A receptor. It can also produce toxicities likely through inactivation of methylcobalamin (vitamin B12) with subsequent neurological, psychiatric, and other sequelae that may be mistaken for other clinical entities. We present a classic presentation of nitrous oxide toxicity, which was missed and urgently referred to infectious diseases with concerns for an infectious neuromyelitis. Knowing the constellation of symptoms and findings and maintaining a high index of suspicion are key to diagnosing nitrous oxide toxicity, which can otherwise easily be missed. Cessation of use, B12 supplementation, and supportive measures such as occupational and physical therapy are helpful for maximizing long-term beneficial outcomes.

Preventive Effects of Baclofen but Not Diazepam on Hippocampal Memory and Glucocorticoid Alterations After Prolonged Alcohol Withdrawal in Mice

Our study aims at comparing in C57/Bl male mice, the impact of repeated injections of baclofen (an agonist of GABAB receptor) or diazepam (a benzodiazepine acting through a positive allosteric modulation of GABAA receptor) administered during the alcohol-withdrawal period on hippocampus-dependent memory impairments and brain regional glucocorticoid dysfunction after a short (1-week) or a long (4-week) abstinence. Hence, mice were submitted to a 6-month alcohol consumption (12%v/v) and were progressively withdrawn to water. Then, after a 1- or 4-weeks abstinence, they were submitted to a contextual memory task followed by measurements of corticosterone concentrations in the dorsal hippocampus (dHPC), the ventral hippocampus (vHPC) and the prefrontal cortex (PFC). Results showed that 1- and 4-week withdrawn mice exhibited a severe memory deficit and a significant abnormal rise of the test-induced increase of corticosterone (TICC) in the dHPC, as compared to water-controls or to mice still under alcohol consumption. Repeated daily systemic administrations of decreasing doses of diazepam (ranged from 0.5 to 0.12 mg/kg) or baclofen (ranged from 1.5 to 0.37 mg/kg) during the last 15 days of the withdrawal period, normalized both memory and TICC scores in the dHPC in 1-week withdrawn animals; in contrast, only baclofen-withdrawn mice showed both normal memory performance and TICC scores in the dHPC after a 4-week withdrawal period. In conclusion, the memory improvement observed in 4-week withdrawn mice administered with baclofen stem from the protracted normalization of glucocorticoid activity in the dHPC, a phenomenon encountered only transitorily in diazepam-treated withdrawn mice.