Moderate ethanol drinking is sufficient to alter Ventral Tegmental Area dopamine neurons activity via functional and structural remodeling of GABAergic transmission

Cannabidiol attenuates precuneus activation during appetitive cue exposure in individuals with alcohol use disorder

Alcohol use disorder (AUD) is a prevalent psychiatric condition characterised by problematic alcohol consumption and craving, necessitating the exploration of novel therapeutic interventions. Cannabidiol (CBD), a non-psychoactive component of cannabis, has shown potential in modulating neural processes associated with substance use disorders including AUD. This study aimed to investigate the effect of CBD on alcohol cue-induced activation of neurocircuitry associated with alcohol craving, and impact on mood, craving, and cognitive functioning in individuals with AUD. In a cross-over, double-blind, randomized trial, 22 non-treatment seeking individuals (M = 29 years) diagnosed with AUD (DSM-V) received either 800 mg of CBD or a matched placebo, completing two respective fMRI sessions. The primary outcome was neural activation in response to alcohol versus control visual cues, measured using a functional magnetic resonance imaging (fMRI) alcohol cue reactivity task. Secondary outcomes included assessments of mood, craving, and cognitive functioning. Region of interest analyses showed no differences in alcohol cue-elicited activation between the CBD and placebo conditions. However, exploratory whole-brain analysis indicated a significant treatment effect of CBD in the precuneus which was independent of cue specificity. There were no significant treatment effects of CBD compared to placebo on acute craving, mood, or cognitive functioning. In non treatment seeking individuals with AUD, CBD modulates precuneus activity during alcohol cue exposure. Further studies examining the effect of CBD on treatment-seeking AUD individuals are warranted.

Prenatal ethanol exposure impairs hippocampal plasticity and cognition in adolescent mice

BACKGROUND

Prenatal alcohol exposure (PAE) induces a wide range of neurodevelopmental disabilities that are grouped under the term 'fetal alcohol spectrum disorders' (FASD). The effects of PAE on brain development are dependent on complex neurochemical events, including modification of AMPA receptors (AMPARs). We have recently found that chronic ethanol (EtOH) exposure decreases AMPA-mediated neurotransmission and expression through the overexpression of the specific microRNA (miR)137 and 501-3p, which target GluA1 AMPA subunit, in the developing hippocampus in vitro. Here, we explored how PAE mice may alter AMPAergic synapses in the hippocampus, and its effects on behavior.

METHODS

To model PAE, we exposed C57Bl/6 pregnant mice to 10 % EtOH during during the first 10 days of gestation (GD 0-10; equivalent to the first trimester of pregnancy in humans). AMPA subunits postsynaptic expression in the hippocampus, electrical properties of CA1 neurons, memory recognition, and locomotor functions were then analyzed in adolescent PAE-exposed offspring.

RESULTS

PAE adolescent mice showed dysregulation of AMPAergic neurotransmission, and increased miR 501-3p expression, associated with a significant reduction of spontaneous AMPA currents and intrinsic somatic excitability. In addition, PAE reduced the phosphorylation of AMPAR-containing GluA1 subunit, despite an increase in its total levels. Of note, the total levels of GluA2 and GluA3 AMPA receptors were enhanced as well. Consistently, at behavioral level, PAE reduced object recognition without altering locomotor activity.

CONCLUSIONS

Our study shows that PAE leads to dysfunctional formation of AMPAergic synapses that could be responsible for neurobehavioral impairments, contributing to the understanding of the pathogenesis of FASD.

A Randomized Controlled Trial of Cognitive Behavioral Therapy for Insomnia During Early Recovery from Alcohol Use Disorder Among Veterans

Study Objectives

1) To determine the efficacy of Cognitive Behavioral Therapy for Insomnia (CBT-I) for improving insomnia, alcohol-related outcomes, and daytime functioning at post-treatment and at 3- and 6-month follow-up, in a largely African American Veteran sample; 2) Evaluate whether improvement in insomnia is associated with a reduction in alcohol-related outcomes post-treatment.

Methods

An RCT of CBT-I (n = 31) compared to Quasi-Desensitization therapy (QDT, n = 32), eight weekly in-person sessions, with assessments at baseline, end of treatment (8 weeks), and 3- and 6-months post-treatment. Primary outcomes were the Insomnia Severity Index (ISI) total score, and Percent Days Abstinent (PDA). Secondary outcomes were sleep diary variables, drinks per day, percentage non-heavy drinking days, Penn Alcohol Craving Scale, PCS and MCS scale (from the SF-12), BDI and STAI-Trait subscale total scores.

Results

Post-treatment data were obtained from 88.9% of participants. Although CBT-I improved insomnia with effect sizes (E.S.) larger than the meta-analytic estimates, QDT was equally efficacious in improving insomnia (E.S. = -1.63 vs. -1.50), improving abstinence (E.S. = 1.54 vs. 1.91) and next-day functioning (E.S. = 0.26 vs. -0.17). Across treatment groups, remission from insomnia was associated with a lower post-treatment alcohol craving score (2.79, 95% CI 1.14, 4.44 vs. 9.51, 95% CI 6.06, 12.95 in non-responders), an effect that persisted for 6 months after treatment.

Conclusions

CBT-I and QDT are equally effective for treating insomnia during early recovery from AUD. Reduced alcohol craving may be a mechanism by which a remission from insomnia improves drinking outcomes.

Relationship between GABA-Ergic System and the Expression of Mephedrone-Induced Reward in Rats-Behavioral, Chromatographic and In Vivo Imaging Study

Mephedrone is a psychoactive drug that increases dopamine, serotonin and noradrenaline levels in the central nervous system via interaction with transporters or monoamines. The aim of the presented study was to assess the role of the GABA-ergic system in the expression of mephedrone-induced reward. For this purpose, we conducted (a) a behavioral evaluation of the impact of baclofen (a GABA_B receptors agonist) and GS39783 (a positive allosteric modulator of GABA_B receptors) on the expression of mephedrone-induced conditioned place preference (CPP) in rats, (b) an ex vivo chromatographic determination of the GABA level in the hippocampi of rats subchronically treated with mephedrone and (c) an in vivo evaluation of GABA hippocampal concentration in rats subchronically administered with mephedrone using magnetic resonance spectroscopy (MRS). The results show that GS39783 (but not baclofen) blocked the expression of CPP induced by (20 mg/kg of) mephedrone. The behavioral effect was consistent with chromatographic analysis, which showed that mephedrone (5 and 20 mg/kg) led to a decrease in GABA hippocampal concentration. Altogether, the presented study provides a new insight into the involvement of the GABA-ergic system in the rewarding effects of mephedrone, implying that those effects are at least partially mediated through GABA_B receptors, which suggests their potential role as new targets for the pharmacological management of mephedrone use disorder.

Substance use, microbiome and psychiatric disorders

Accumulating evidence from several studies has shown association between substance use, dysregulation of the microbiome and psychiatric disorders such as depression, anxiety, and psychosis. Many of the abused substances such as cocaine and alcohol have been shown to alter immune signaling pathways and cause inflammation in both the periphery and the central nervous system (CNS). In addition, these substances of abuse also alter the composition and function of the gut microbiome which is known to play important roles such as the synthesis of neurotransmitters and metabolites, that affect the CNS homeostasis and consequent behavioral outcomes. The emerging interactions between substance use, microbiome and CNS neurochemical alterations could contribute to the development of psychiatric disorders. This review provides an overview of the associative effects of substance use such as alcohol, cocaine, methamphetamine, nicotine and opioids on the gut microbiome and psychiatric disorders involving anxiety, depression and psychosis. Understanding the relationship between substance use, microbiome and psychiatric disorders will provide insights for potential therapeutic targets, aimed at mitigating these adverse outcomes.