The effect of constant darkness and circadian resynchronization on the recovery of alcohol hangover

Endogenous circadian time genes expressions in the liver of mice under constant darkness

BACKGROUND

The circadian rhythms regulate physiological functions and metabolism. Circadian Time (CT) is a unit to quantify the rhythm of endogenous circadian clock, independent of light influence. To understand the gene expression changes throughout CT, C57BL/6 J mice were maintained under constant darkness (DD) for 6 weeks, and the liver samples were collected starting at 9:00 AM (CT1), and every 4 h in a 24-h cycle (CT5, CT9, CT13, CT17 and CT21). Total RNA was extracted and subjected to RNA-Seq data (deposited as GSE 133342, L-DD). To compare gene oscillation pattern under normal light-dark condition (LD, GSE114400) and short time (2 days) dark-dark condition (S-DD, GSE70497), these data were retried from GEO database, and the trimmed mean of M-values normalization was used to normalize the three RNA-seq data followed by MetaCycle analysis.

RESULTS

Approximate 12.1% of the genes under L-DD exhibited significant rhythmically expression. The top 5 biological processes enriched in L-DD oscillation genes were mRNA processing, aromatic compound catabolic process, mitochondrion organization, heterocycle catabolic process and cellular nitrogen compound mitotic catabolic process. The endogenous circadian rhythms of clock genes, P450 genes and lipid metabolism genes under L-DD were further compared with LD and S-DD. The oscillation patterns were similar but the period and amplitude of those oscillation genes were slightly altered. RT-qPCR confirmed the selected RNA sequence findings.

CONCLUSIONS

This is the first study to profile oscillation gene expressions under L-DD. Our data indicate that clock genes, P450 genes and lipid metabolism genes expressed rhythmically under L-DD. Light was not the necessary factor for persisting circadian rhythm but influenced the period and amplitude of oscillation genes.

Pharmacological manipulation of the ghrelin system and alcohol hangover symptoms in heavy drinking individuals: Is there a link?

Ghrelin, an orexigenic peptide synthesized in the stomach, is a key player in the gut-brain axis. In addition to its role in regulating food intake and energy homeostasis, ghrelin has been shown to modulate alcohol-related behaviors. Alcohol consumption frequently results in hangover, an underexplored phenomenon with considerable medical, psychological, and socioeconomic consequences. While the pathophysiology of hangover is not clear, contributions of mechanisms such as alcohol-induced metabolic/endocrine changes, inflammatory/immune response, oxidative stress, and gut dysbiosis have been reported. Interestingly, these mechanisms considerably overlap with ghrelin's physiological functions. Here, we investigated whether pharmacological manipulation of the ghrelin system may affect alcohol hangover symptoms. Data were obtained from two placebo-controlled laboratory studies. The first study tested the effects of intravenous (IV) ghrelin and consisted of two experiments: a progressive-ratio IV alcohol self-administration (IV-ASA) and a fixed-dose IV alcohol clamp. The second study tested the effects of an oral ghrelin receptor inverse agonist (PF-5190457) and included a fixed-dose oral alcohol administration experiment. Alcohol hangover data were collected the morning after each alcohol administration experiment using the Acute Hangover Scale (AHS). IV ghrelin, compared to placebo, significantly reduced alcohol hangover after IV-ASA (p = 0.04) and alcohol clamp (p = 0.04); PF-5190457 had no significant effect on AHS scores. Females reported significantly higher hangover symptoms than males following the IV-ASA experiment (p = 0.04), but no gender × drug condition (ghrelin vs. placebo) effect was found. AHS total scores were positively correlated with peak subjective responses, including 'stimulation' (p = 0.08), 'sedation' (p = 0.009), 'feel high' (p = 0.05), and 'feel intoxicated' (p = 0.03) during the IV-ASA. IV ghrelin blunted the positive association between alcohol sedation and hangover as shown by trend-level drug × sedation effect (p = 0.08). This is the first study showing that exogenous ghrelin administration, but not ghrelin receptor inverse agonism, affects hangover symptoms. Future research should investigate the potential mechanism(s) underlying this effect.

Proceeding of the 8th Alcohol Hangover Research Group Meeting

Alcohol hangover is one of the most commonly experienced consequences of alcohol consumption. An alcohol hangover develops as the blood alcohol concentrations (BAC) approaches zero, and is characterized by a general feeling of misery. More insight into the pathology of an alcohol hangover needs to be gained, in order to enhance the understanding of the area, and as a potential contribution to the innovation of a preventative or hangover curing treatment. The Alcohol Hangover Research Group (AHRG) was founded to support the area of alcohol hangover. This proceeding describes the latest findings in the area of alcohol hangovers, and future research plans, discussed at the 8th Alcohol Hangover Research Group meeting, held on June 25, 2016, New Orleans, USA. Novel insight in potential causes, consequences, and treatment of alcohol hangover were revealed during the meeting, as well as further research plans to examine biomarkers of recent alcohol consumption, immune functioning, alcohol metabolism, and potential treatments.

Free radical production and antioxidant status in brain cortex non-synaptic mitochondria and synaptosomes at alcohol hangover onset

Alcohol hangover (AH) is the pathophysiological state after a binge-like drinking. We have previously demonstrated that AH induced bioenergetics impairments in a total fresh mitochondrial fraction in brain cortex and cerebellum. The aim of this work was to determine free radical production and antioxidant systems in non-synaptic mitochondria and synaptosomes in control and hangover animals. Superoxide production was not modified in non-synaptic mitochondria while a 17.5% increase was observed in synaptosomes. A similar response was observed for cardiolipin content as no changes were evidenced in non-synaptic mitochondria while a 55% decrease in cardiolipin content was found in synaptosomes. Hydrogen peroxide production was 3-fold increased in non-synaptic mitochondria and 4-fold increased in synaptosomes. In the presence of deprenyl, synaptosomal H₂O₂ production was 67% decreased in the AH condition. Hydrogen peroxide generation was not affected by deprenyl addition in non-synaptic mitochondria from AH mice. MAO activity was 57% increased in non-synaptic mitochondria and 3-fold increased in synaptosomes. Catalase activity was 40% and 50% decreased in non-synaptic mitochondria and synaptosomes, respectively. Superoxide dismutase was 60% decreased in non-synaptic mitochondria and 80% increased in synaptosomal fractions. On the other hand, GSH (glutathione) content was 43% and 17% decreased in synaptosomes and cytosol. GSH-related enzymes were mostly affected in synaptosomes fractions by AH condition. Acetylcholinesterase activity in synaptosomes was 11% increased due to AH. The present work reveals that AH provokes an imbalance in the cellular redox homeostasis mainly affecting mitochondria present in synaptic terminals.

Circadian Modulation of Alcohol-Induced Sedation and Recovery in Male and Female Drosophila

Delineating the factors that affect behavioral and neurological responses to alcohol is critical to facilitate measures for preventing or treating alcohol abuse. The high degree of conserved molecular and physiological processes makes Drosophila melanogaster a valuable model for investigating circadian interactions with alcohol-induced behaviors and examining sex-specific differences in alcohol sensitivity. We found that wild-type Drosophila exhibited rhythms in alcohol-induced sedation under light-dark and constant dark conditions with considerably greater alcohol exposure necessary to induce sedation during the late (subjective) day and peak sensitivity to alcohol occurring during the late (subjective) night. The circadian clock also modulated the recovery from alcohol-induced sedation with flies regaining motor control significantly faster during the late (subjective) day. As predicted, the circadian rhythms in sedation and recovery were absent in flies with a mutation in the circadian gene period or arrhythmic flies housed in constant light conditions. Flies lacking a functional circadian clock were more sensitive to the effects of alcohol with significantly longer recovery times. Similar to other animals and humans, Drosophila exhibit sex-specific differences in alcohol sensitivity. We investigated whether the circadian clock modulated the rhythms in the loss-of-righting reflex, alcohol-induced sedation, and recovery differently in males and females. We found that both sexes demonstrated circadian rhythms in the loss-of-righting reflex and sedation with the differences in alcohol sensitivity between males and females most pronounced during the late subjective day. Recovery of motor reflexes following alcohol sedation also exhibited circadian modulation in male and female flies, although the circadian clock did not modulate the difference in recovery times between the sexes. These studies provide a framework outlining how the circadian clock modulates alcohol-induced behaviors in Drosophila and identifies sexual dimorphisms in the circadian modulation of alcohol behaviors.