Intermittent Alcohol Research Articles

Intermittent alcohol consumption changes the hepatocyte ploidy

Introdução: O álcool é metabolizado principalmente pelos hepatócitos no fígado. Essas células devem ser alvos diretos de estresse, que pode culminar em adaptações celulares antes da progressão da doença hepática alcoólica. A poliploidização tem sido sugerida como uma adaptação genética ao estresse hepatotóxico. Este estudo teve como objetivo investigar como a administração intermitente de álcool poderia afetar os fenótipos nucleares dos hepatócitos. Métodos: Os ratos foram tratados com etanol a 5% (v/v) e 20% (v/v) em água potável durante a noite durante 80 dias. Posteriormente, o fígado foi dissecado e processado histologicamente. A análise histopatológica foi realizada em cortes corados com hematoxilina e eosina (H&E). A análise histomorfométrica dos núcleos dos hepatócitos foi realizada em seções coradas com Feulgen usando ImageJ. Resultados: Congestão severa foi observada no grupo tratado com etanol 20%. Nenhuma diferença no acúmulo de gordura nos hepatócitos ou infiltração de células inflamatórias foi observada entre os grupos controle e tratado com etanol. Após os hepatócitos terem diferentes ploidias, o conteúdo de DNA dos núcleos foi determinado com base nos valores de densidade óptica integrados obtidos a partir da análise de imagens digitais de cortes de fígado corados com Feulgen. Mais núcleos com alto conteúdo de DNA (8C) foram encontrados nos animais tratados com etanol. Conclusão: Esses resultados mostram que o álcool induz a poliploidização dos hepatócitos, mesmo em doses em que os sinais típicos da doença hepática alcoólica, como esteatose e hepatite, não são significativos.

L-3-n-butylphthalide alleviates intermittent alcohol exposure-induced hypothalamic cell apoptosis via inhibiting the IRE1α-ASK1-JNK pathway in adolescent rats.

Exposure to alcohol can induce different degrees of damage to various tissues and organs, and brain is the most vulnerable part affected by alcohol. However, there is no detailed report on whether intermittent alcohol exposure can result in pathological changes in the hypothalamus of adolescent rats and the detailed mechanism. This study investigated pathological changes in the hypothalamus, probed the levels of inflammatory factors, and detected the expression of proteins related to endoplasmic reticulum stress (ERS) to determine whether ERS is involved in the injury process of the hypothalamus and the protective mechanism of L-3-n-butylphthalide (L-NBP). The results showed that intermittent alcohol exposure induced hypothalamic nerve injury, including cell apoptosis, increased the levels of inflammatory factors, and upregulated the expression of glucose-regulated protein 78 (GRP78), p-Inositol Requiring Enzyme 1α (p-IRE1α), apoptosis signal-regulating kinase 1 (ASK1), and p-c-Jun N-terminal kinase (p-JNK)). Tauroursodeoxycholic acid (TUDCA), an ERS inhibitor, significantly reduced the pathological damage described above. The increases in the levels of inflammatory factors, pathological injury, and increased levels of proteins associated with the IRE1α-ASK1-JNK pathway were alleviated by L-NBP. The present study indicated that intermittent alcohol exposure could lead to hypothalamic cell apoptosis in adolescent rats and L-NBP could alleviate the above injury by inhibiting the IRE1α-ASK1-JNK pathway. Abbreviations: Ang-2, Angiopoietin-2; ASK1, Apoptosis signal-regulating kinase 1; ER, Endoplasmic reticulum; ERS, Endoplasmic reticulum stress; ELISA, Enzyme-linked immunosorbent assay; GFAP, Glial fibrillary acidic protein; GRP78, Glucose-regulated protein 78; IBA1, Ionized calcium binding adapter molecule 1; i.p., Intraperitoneal; IRE1α, Inositol Requiring Enzyme 1α; JNK, c-Jun N-terminal kinase; L-NBP, L-3-n-butylphthalide; PND, Postnatal day; PVDF, Polyvinylidene difluoride; SDS-PAGE, Sodium dodecyl sulfate-polyacrylamide gel electrophoresis; TRAF2, TNF-receptor associated factor 2; TUDCA, Tauroursodeoxycholic acid; VEGF, Vascular endothelial growth factor.

Effects of daridorexant on rest/wake activity patterns and drinking in adult rats exposed to chronic ethanol vapor in adolescence.

Disturbance in sleep and activity rhythms are significant health risks associated with alcohol use during adolescence. Many investigators support the theory of a reciprocal relationship between disrupted circadian rhythms, sleep patterns, and alcohol usage. However, in human studies it is difficult to disentangle other factors (i.e. lifestyle, psychiatric, genetic) when determining what is causal in the relationship between substance use and sleep/activity disruptions. To this end, we used an animal model of adolescent alcohol exposure whereby male and female Wistar rats are exposed to 5 weeks of intermittent alcohol vapor during adolescence (P22-P57). Five days after ethanol vapor rats were allowed to select to drink alcohol or water in a two-bottle choice procedure for a period of 5 hours, 4 days a week for 6 weeks. Activity data was collected using a "Fitbit-like" device during vapor exposure, during acute withdrawal, and after 3 weeks of protracted withdrawal. Significant changes in rest/wake activity and circadian measures were seen during 24-hour withdrawal and after 3 weeks of withdrawal. Four weeks following withdrawal, the effects of the dual orexin antagonist, Daridorexant, (DAX 30mg, 100mg, or vehicle control), on alcohol drinking and rest and activity rhythms were assessed over a 24h period. Both daridorexant doses led to changes in circadian measures and rest/wake activity patterns. These results showed that daridorexant reduced activity, but it did not improve rest quality as measured by the mean inactive episode duration and inactive fragmentation ratio. Additionally, we did not find a significant difference in drinking behavior in animals treated with the orexin antagonist. Thus, it appears that data from this animal model do not support the use of this drug to improve adolescent alcohol-induced sleep disturbance and/or to decrease alcohol drinking.

Effects of chronodisruption and alcohol consumption on gene expression in reward-related brain areas in female rats.

Circadian dysfunction caused by exposure to aberrant light-dark conditions is associated with abnormal alcohol consumption in humans and animal models. Changes in drinking behavior have been linked to alterations in clock gene expression in reward-related brain areas, which could be attributed to either the effect of chronodisruption or alcohol. To date, however, the combinatory effect of circadian disruption and alcohol on brain functions is less understood. Moreover, despite known sex differences in alcohol drinking behavior, most research has been carried out on male subjects only, and therefore implications for females remain unclear. To address this gap, adult female rats housed under an 11 h/11 h light-dark cycle (LD22) or standard light conditions (LD24, 12 h/12 h light-dark) were given access to an intermittent alcohol drinking protocol (IA20%) to assess the impact on gene expression in brain areas implicated in alcohol consumption and reward: the prefrontal cortex (PFC), nucleus accumbens (NAc), and dorsal striatum (DS). mRNA expression of core clock genes (Bmal1, Clock, Per2), sex hormone receptors (ERβ, PR), glutamate receptors (mGluR5, GluN2B), a calcium-activated channel (Kcnn2), and an inflammatory cytokine (TNF-α) were measured at two-time points relative to the locomotor activity cycle. Housing under LD22 did not affect alcohol intake but significantly disrupted circadian activity rhythms and reduced locomotion. Significant changes in the expression of Bmal1, ERβ, and TNF-α were primarily related to the aberrant light conditions, whereas changes in Per2 and PR expression were associated with the effect of alcohol. Collectively, these results indicate that disruption of circadian rhythms and/or intermittent alcohol exposure have distinct effects on gene expression in the female brain, which may have implications for the regulation of alcohol drinking, addiction, and, ultimately, brain health.

Sex-dependent effects of acute stress and alcohol exposure during adolescence on mRNA expression of brain signaling systems involved in reward and stress responses in young adult rats

BackgroundAdolescent stress and alcohol exposure increase the risk of maladaptive behaviors and mental disorders in adulthood, with distinct sex-specific differences. Understanding the mechanisms underlying these early events is crucial for developing targeted prevention and treatment strategies.MethodsMale and female Wistar rats were exposed to acute restraint stress and intermittent alcohol during adolescence. We assessed lasting effects on plasma corticosterone (CORT) and adrenocorticotropic hormone (ACTH) levels, and mRNA expression of genes related to corticotropin releasing hormone (CRH), neuropeptide Y (NPY), corticoid, opioid, and arginine vasopressin systems in the amygdala and hypothalamus.ResultsThe main findings are as follows: (1) blood alcohol concentrations (BAC) increased after the final alcohol administration, but stressed males had lower BAC than non-stressed males; (2) Males gained significantly more weight than females; (3) Stressed females showed higher ACTH levels than non-stressed females, with no changes in males; (4) Stress increased CORT levels in males, while stressed, alcohol-treated females had lower CORT levels than non-stressed females; (5) CRH: Females had lower Crhr1 levels in the amygdala, while alcohol reduced Crhr2 levels in males but not females. Significant interactions among sex, stress, and alcohol were found in the hypothalamus, with distinct patterns between sexes; (6) NPY: In the amygdala, stress reduced Npy and Npy1r levels in males but increased them in females. Alcohol decreased Npy2r levels in males, with varied effects in females. Similar sex-specific patterns were observed in the hypothalamus; (7) Corticoid system: Stress and alcohol had complex, sex-dependent effects on Pomc, Nr3c1, and Nr3c2 in both brain regions; (8) Opioid receptors: Stress and alcohol blunted the elevated expression of Oprm1, Oprd1, and Oprk1 in the amygdala of males and the hypothalamus of females; (8) Vasopressin: Stress and alcohol interacted significantly to affect Avp and Avpr1a expression in the amygdala, with stronger effects in females. In the hypothalamus, alcohol increased Avp levels in females.ConclusionsThis study demonstrates that adolescent acute stress and alcohol exposure induce lasting, sex-specific alterations in systems involved in reward and stress responses. These findings emphasize the importance of considering sex differences in the prevention and management of HPA dysfunction and psychiatric disorders.

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.

BCI Improves Alcohol-Induced Cognitive and Emotional Impairments by Restoring pERK-BDNF.

Binge drinking causes a range of problems especially damage to the nervous system, and the specific neural mechanism of brain loss and behavioral abnormalities caused by which is still unclear. Extracellular regulated protein kinases (ERK) maintain neuronal survival, growth, and regulation of synaptic plasticity by phosphorylating specific transcription factors to regulate expression of brain-derived neurotrophic factor (BDNF). Dual-specific phosphatase 1 (DUSP1) and DUSP6 dephosphorylate tyrosine and serine/threonine residues in ERK1/2 to inactivate them. To investigate the molecular mechanism by which alcohol affects memory and emotion, a chronic intermittent alcohol exposure (CIAE) model was established. The results demonstrated that mice in the CIAE group developed short-term recognition memory impairment and anxiety-like behavior; meanwhile, the expression of DUSP1 and DUSP66 in the mPFC was increased, while the levels of p-ERK and BDNF were decreased. Micro-injection of DUSP1/6 inhibitor BCI into the medial prefrontal cortex (mPFC) restored the dendritic morphology by reversing the activity of ERK-BDNF and ultimately improved cognitive and emotional impairment caused by CIAE. These findings indicate that CIAE inhibits ERK-BDNF by increasing DUSP1/6 in the mPFC that may be associated with cognitive and emotional deficits. Consequently, DUSP1 and DUSP6 appear to be potential targets for the treatment of alcoholic brain disorders.

Effects of cannabidiol, with and without ∆9-tetrahydrocannabinol, on anxiety-like behavior following alcohol withdrawal in mice.

Alcohol use disorder (AUD) is commonly associated with anxiety disorders and enhanced stress-sensitivity; symptoms that can worsen during withdrawal to perpetuate continued alcohol use. Alcohol increases neuroimmune activity in the brain. Our recent evidence indicates that alcohol directly modulates neuroimmune function in the central amygdala (CeA), a key brain region regulating anxiety and alcohol intake, to alter neurotransmitter signaling. We hypothesized that cannabinoids, such as cannabidiol (CBD) and ∆9-tetrahydrocannabinol (THC), which are thought to reduce neuroinflammation and anxiety, may have potential utility to alleviate alcohol withdrawal-induced stress-sensitivity and anxiety-like behaviors via modulation of CeA neuroimmune function. We tested the effects of CBD and CBD:THC (3:1 ratio) on anxiety-like behaviors and neuroimmune function in the CeA of mice undergoing acute (4-h) and short-term (24-h) withdrawal from chronic intermittent alcohol vapor exposure (CIE). We further examined the impact of CBD and CBD:THC on alcohol withdrawal behaviors in the presence of an additional stressor. We found that CBD and 3:1 CBD:THC increased anxiety-like behaviors at 4-h withdrawal. At 24-h withdrawal, CBD alone reduced anxiety-like behaviors while CBD:THC had mixed effects, showing increased center time indicating reduced anxiety-like behaviors, but increased immobility time that may indicate increased anxiety-like behaviors. These mixed effects may be due to altered metabolism of CBD and THC during alcohol withdrawal. Immunohistochemical analysis showed decreased S100β and Iba1 cell counts in the CeA at 4-h withdrawal, but not at 24-h withdrawal, with CBD and CBD:THC reversing alcohol withdrawal effects.. These results suggest that the use of cannabinoids during alcohol withdrawal may lead to exacerbated anxiety depending on timing of use, which may be related to neuroimmune cell function in the CeA.

Assessing the Influence of Intermittent Alcohol Access on Acrylamide-Induced Neuronal Toxicity in an Experimental Rat Model.

Tobacco and alcohol have been identified as health risk behaviors associated with significant unfavorable health consequences, ranking within the list of the top ten causes of mortality and disability-adjusted life years (DALY). The combustion of tobacco leads to the formation of acrylamide (ACR), which is well known for its neurotoxic effects. Similarly, alcohol consumption has also been widely recognized for its neurotoxic effects. Both substances can affect neurons and neuroglia cells through various pathways. This study sought to examine the impacts of co-administration of ACR and intermittent-access ethanol (IAE) consumption over a period of one month. The experimental group received 20 mg/kg of ACR, administered orally, along with IAE of 20% ethanol sessions lasting 24 h, three times per week. The cognitive outcomes were assessed utilizing the elevated plus maze (EPM), which was employed as a means of assessing the capability to learn and remember, the novel object recognition (NOR) test, which was employed to assess recognition memory, and the Y-maze, which was used to explore a new environment and navigate. Additionally, ELISA assays were performed to examine underlying mechanisms, including markers associated with inflammation (NF-κB, PGE2, and TNF-α), apoptosis (Bcl2, Bax, and Caspase-3), and oxidative stress (MDA, catalase, and GSH). These markers were assessed in the brain homogenate as part of the investigation. Furthermore, a histopathological study was conducted. The findings indicated that NF-κB levels increased significantly in the combination of ACR and IAE groups (ACR + IAE) compared to either the ACR-alone or IAE-alone groups. However, parallel changes were observed in TNF-α, PGE2, Bax, Bcl-2, Caspase-3, GSH, and CAT levels when comparing the ACR + IAE group to the ACR-alone group. Comparable alterations were noted between the ACR + IAE treatment and IAE-alone groups in TNF-α, Bcl-2, MDA, GSH, and CAT levels. Moreover, the histopathological analysis revealed significant changes between the ACR + IAE and the ACR- or IAE-alone groups. Regarding memory parameters assessed using tests including EPM, NOR, and Y-maze, considerable changes were observed across all treatment groups as opposed to the control. Surprisingly, there were no notable differences in the NOR and Y-maze tasks between the alone and combination treatment. Further study is necessary to explore the long-term alteration of co-administering ACR and IAE on behavior, memory, and neurotoxicity-related mechanisms, in order to elucidate their combined effects more clearly.

Protein kinase C epsilon-mediated modulation of T-type calcium channels underlies alcohol withdrawal hyperexcitability in the midline thalamus.

Millions of people struggle with alcohol use disorder (AUD). Abrupt abstinence after a period of chronic alcohol use can precipitate the alcohol withdrawal syndrome (AWS), which includes hyperexcitability and, potentially, seizures. We have shown that T-type Ca2+ channels are novel, sensitive targets of alcohol, an effect that is dependent upon protein kinase C (PKC). The purpose of this study was to (1) understand midline thalamic neuronal hyperexcitability during alcohol withdrawal and its dependence on PKC; (2) characterize T channel functional changes using both current clamp and voltage clamp methods; and (3) determine which PKC isoform may be responsible for alcohol withdrawal (WD) effects. Whole-cell patch clamp recordings were performed in midline thalamic neurons in brain slices prepared from C57bl/6 mice that underwent chronic intermittent alcohol exposure in a standard vapor chamber model. The recordings were compared to those from air-exposed controls. T-channel inactivation curves and burst responses were acquired through voltage-clamp and current-clamp recordings, respectively. Whole-cell voltage clamp recordings of native T-type current exhibited a depolarizing shift in the voltage-dependency of inactivation during alcohol withdrawal compared to air-exposed controls. A PKCε translocation inhibitor peptide mitigated this change. Current clamp recordings demonstrated more spikes per burst during alcohol withdrawal. Consistent with voltage clamp findings, the PKCɛ translocation inhibitor peptide reduced the number of spikes per burst after WD. We found that alcohol WD produces T channel-mediated hyperexcitability in the midline thalamus, produced in part by a shift in the inactivation curve consistent with greater availability of T current. WD effects on T current inactivation were reduced to control levels by blocking PKCε translocation. Our results demonstrate that PKCε translocation plays an important role in the regulation of alcohol withdrawal-induced hyperexcitability in midline thalamic circuitry.

Inhibition of the Sodium-Calcium Exchanger Reverse Mode Activity Reduces Alcohol Consumption in Rats.

Excessive and uncontrolled consumption of alcohol can cause alcohol use disorder (AUD), but its pharmacological mechanisms are not fully understood. Inhibiting the reverse mode activity of the sodium-calcium exchanger (NCX) can reduce the risk of alcohol withdrawal seizures, suggesting that NCX could play a role in controlling alcohol consumption. Here, we investigated how two potent inhibitors of NCX reverse mode activity, SN-6 (NCX1) and KB-R7943 (NCX3), affect voluntary alcohol consumption in adult male and female rats using the intermittent alcohol access two-bottle choice paradigm. Initially, animals were trained to drink 7.5% ethanol and water for four weeks before administering SN-6 and KB-R7934. Afterward, their alcohol intake, preference, and water intake were recorded 2 and 24 h after exposure to water and 7.5% ethanol. SN-6 significantly reduced alcohol consumption by 48% in male and 36% in female rats without affecting their water intake. Additionally, SN-6 significantly reduced alcohol preference in females by 27%. However, KB-R7943 reduced alcohol consumption by 42% in female rats and did not affect alcohol preference or water intake. These findings suggest that alcohol exposure increased NCX reverse activity, and targeting NCX1 could be an effective strategy for reducing alcohol consumption in subjects susceptible to withdrawal seizures.

LY2444296, a κ-opioid receptor antagonist, selectively reduces alcohol drinking in male and female Wistar rats with a history of alcohol dependence

Alcohol use disorder (AUD) remains a major public health concern. The dynorphin (DYN)/κ-opioid receptor (KOP) system is involved in actions of alcohol, particularly its withdrawal-associated negative affective states. This study tested the ability of LY2444296, a selective, short-acting, KOP antagonist, to decrease alcohol self-administration in dependent male and female Wistar rats at 8 h abstinence. Animals were trained to orally self-administer 10% alcohol (30 min/day for 21 sessions) and were made dependent via chronic intermittent alcohol vapor exposure for 6 weeks or exposed to air (nondependent). After 6 weeks, the effect of LY2444296 (0, 3, and 10 mg/kg, p.o.) was tested on alcohol self-administration at 8 h of abstinence. A separate cohort of rats was prepared in parallel, and their somatic withdrawal signs and alcohol self-administration were measured after LY2444296 administration at 8 h, 2 weeks, and 4 weeks abstinence. LY2444296 at 3 and 10 mg/kg significantly reduced physical signs of withdrawal in dependent rats at 8 h abstinence, only. Furthermore, 3 and 10 mg/kg selectively decreased alcohol self-administration in dependent rats at only 8 h abstinence. These results highlight the DYN/KOP system in actions of alcohol during acute abstinence, suggesting KOP antagonism could be beneficial for mitigating acute withdrawal signs and, in turn, significantly reduce excessive alcohol consumption associated with AUD.

Subthalamic high-frequency deep brain stimulation reduces addiction-like alcohol use and the possible negative influence of a peer presence.

The immediate social context significantly influences alcohol consumption in humans. Recent studies have revealed that peer presence could modulate drugs use in rats. The most efficient condition to reduce cocaine intake is the presence of a stranger peer, naive to drugs. Deep brain stimulation (DBS) of the Subthalamic Nucleus (STN), which was shown to have beneficial effects on addiction to cocaine or alcohol, also modulates the protective influence of peer's presence on cocaine use. This study aimed to: 1) explore how the presence of an alcohol-naive stranger peer affects recreational and escalated alcohol intake, and 2) assess the involvement of STN on alcohol use and in the modulation induced by the presence of an alcohol-naïve stranger peer. Rats with STN DBS and control animals self-administered 10% (v/v) ethanol in presence, or absence, of an alcohol-naive stranger peer, before and after escalation of ethanol intake (observed after intermittent alcohol (20% (v/v) ethanol) access). Neither STN DBS nor the presence of an alcohol-naive stranger peer modulated significantly recreational alcohol intake. After the escalation procedure, STN DBS reduced ethanol consumption. The presence of an alcohol-naive stranger peer increased consumption only in low drinkers, which effect was suppressed by STN DBS. These results highlight the influence of a peer's presence on escalated alcohol intake, and confirm the role of STN in addiction-like alcohol intake and in the social influence on drug consumption.

Ethanol’s interaction with BK channel α subunit residue K361 does not mediate behavioral responses to alcohol in mice

Large conductance potassium (BK) channels are among the most sensitive molecular targets of ethanol and genetic variations in the channel-forming α subunit have been nominally associated with alcohol use disorders. However, whether the action of ethanol at BK α influences the motivation to drink alcohol remains to be determined. To address this question, we first tested the effect of systemically administered BK channel modulators on voluntary alcohol consumption in C57BL/6J males. Penitrem A (blocker) exerted dose-dependent effects on moderate alcohol intake, while paxilline (blocker) and BMS-204352 (opener) were ineffective. Because pharmacological manipulations are inherently limited by non-specific effects, we then sought to investigate the behavioral relevance of ethanol’s direct interaction with BK α by introducing in the mouse genome a point mutation known to render BK channels insensitive to ethanol while preserving their physiological function. The BK α K361N substitution prevented ethanol from reducing spike threshold in medial habenula neurons. However, it did not alter acute responses to ethanol in vivo, including ataxia, sedation, hypothermia, analgesia, and conditioned place preference. Furthermore, the mutation did not have reproducible effects on alcohol consumption in limited, continuous, or intermittent access home cage two-bottle choice paradigms conducted in both males and females. Notably, in contrast to previous observations made in mice missing BK channel auxiliary β subunits, the BK α K361N substitution had no significant impact on ethanol intake escalation induced by chronic intermittent alcohol vapor inhalation. It also did not affect the metabolic and locomotor consequences of chronic alcohol exposure. Altogether, these data suggest that the direct interaction of ethanol with BK α does not mediate the alcohol-related phenotypes examined here in mice.

Effects of binge alcohol administration on tauopathy and neuroinflammation in PS19 mice

AbstractBackgroundIt is estimated that 50 million people worldwide are suffering from dementia, the most common being Alzheimer’s disease (AD). Even as the population ages and the incidence of AD increases, there are limited disease‐modifying treatments to date. Alcohol use disorders (AUD) have been identified as a modifiable risk factors for developing AD. Heavy alcohol intake in elderly individuals is associated with more rapid progression of AD pathology and an elevated neuroinflammatory state. The objective of this study was to investigate the interaction of high ethanol ‘binge’ treatments in a mouse model of tauopathy.MethodPS19 mice, a widely used tauopathy model, were subjected to a 5‐week binge paradigm of IP ethanol administration, 3.0g/kg, three times per week, beginning at 6 months of age. Prior to initiation of the binge ethanol regimen, mice received subcutaneous biotransponder implantations to record body temperature changes in response to ethanol. Blood ethanol concentrations were determined in a subset of mice at 30 minutes following the last ethanol administration. Frailty measures were completed one week after ethanol administration. NanoString unbiased gene expression, MesoScale Discovery ELISA, Western blotting, and Immunohistochemistry were performed to examine neuroimmune changes and markers of tau pathology.ResultOverall, ethanol treatment resulted in reduced body weight, which was further exacerbated in female PS19 mice.. Measures of frailty (i.e. cerebellar ataxia and grip strength) were impaired in PS19 mice, however, female PS19 mice receiving ethanol treatment had the greatest impairments compared to WT controls. Alterations in inflammatory signaling pathways were observed in the PS19 animals receiving alcohol treatment compared to PS19 or WT mice.ConclusionWe have examined the result of intermittent alcohol exposure on tau pathogenesis. In the present study we found that alcohol can induce biometric and behavioral changes in mice, which are further exacerbated by alcohol. Transcriptomic analysis indicated changes in both innate and inflammatory signaling, suggesting a increased inflammatory response in the ethanol treated animals. Taken together, these results suggest that intermittent environmental influences, such as ethanol, can result in more rapid progression of AD pathogenesis.

Alcohol Consumption During Adolescence Alters the Cognitive Function in Adult Male Mice by Persistently Increasing Levels of DUSP6.

Binge alcohol drinking during adolescence has long-term effects on the adult brain that alter brain structure and behaviors, but the underlying mechanisms remain poorly understood. Extracellular signal-regulated kinase (ERK) is involved in the synaptic plasticity and pathological brain injury by regulating the expression of cyclic adenosine monophosphate response element binding protein (CREB) and brain-derived neurotrophic factor (BDNF). Dual-specificity phosphatase 6 (DUSP6) is a critical effector that dephosphorylates ERK1/2 to control the basal tone, amplitude, and duration of ERK signaling. To explore DUSP6 as a regulator of ERK signaling in the mPFC and its impact on long-term effects of alcohol, a male mouse model of adolescent intermittent alcohol (AIA) exposure was established. Behavioral experiments showed that AIA did not affect anxiety-like behavior or sociability in adulthood, but significantly damaged new object recognition and social recognition memory. Molecular studies further found that AIA reduced the levels of pERK-pCREB-BDNF-PSD95/NR2A involved in synaptic plasticity, while DUSP6 was significantly increased. Intra-mPFC infusion of AAV-DUSP6-shRNA restored the dendritic spine density and postsynaptic density thickness by reversing the level of p-ERK and its downstream molecular expression, and ultimately repaired adult cognitive impairment caused by chronic alcohol exposure during adolescence. These findings indicate that AIA exposure inhibits ERK-CREB-BDNF-PSD95/NR2A by increasing DUSP6 in the mPFC in adulthood that may be associated with long-lasting cognitive deficits.

Adolescent Intermittent Ethanol Drives Modest Neuroinflammation but Does Not Escalate Drinking in Male Rats.

During adolescence, the brain is highly susceptible to alcohol-induced damage and subsequent neuroimmune responses, effects which may enhance development of an alcohol use disorder (AUD). Neuroimmune reactions are implicated in adolescent alcohol exposure escalating adulthood drinking. Therefore, we investigated whether intermittent alcohol exposure in male, adolescent rats (AIE) escalated adult drinking via two-bottle choice (2BC). We also examined the influence of housing environment across three groups: standard (group-housed with enrichment during 2BC), impoverished (group-housed without enrichment during 2BC), or isolation (single-housed without bedding or enrichment throughout). In the standard group immediately after AIE/saline and after 2BC, we also examined the expression of microglial marker, Iba1, reactive astrocyte marker, vimentin, and neuronal cell death dye, FluoroJade B (FJB). We did not observe an escalation of adulthood drinking following AIE, regardless of housing condition. Further, only a modest neuroimmune response occurred after AIE in the standard group: no significant microglial reactivity or neuronal cell death was apparent using this model, although some astrocyte reactivity was detected in adolescence following AIE that resolved by adulthood. These data suggest that the lack of neuroimmune response in adolescence in this model may underlie the lack of escalation of alcohol drinking, which could not be modified through isolation stress.

Adolescent intermittent alcohol exposure produces strain-specific cross-sensitization to nicotine and other behavioral adaptations in adulthood in C57BL/6J and DBA/2J mice

Adolescent alcohol exposure is associated with lasting behavioral changes in humans and in mice. Prior work from our laboratory and others have demonstrated that C57BL/6J and DBA/2J mice differ in sensitivity to some effects of acute alcohol exposure during adolescence and adulthood. However, it is unknown if these strains differ in cognitive, anxiety-related, and addiction-related long-term consequences of adolescent intermittent alcohol exposure. This study examined the impact of a previously validated adolescent alcohol exposure paradigm (2–3 g/kg, i.p., every other day PND 30–44) in C57BL/6J and DBA/2J male and female mice on adult fear conditioning, anxiety-related behavior (elevated plus maze), and addiction-related phenotypes including nicotine sensitivity (hypothermia and locomotor depression) and alcohol sensitivity (loss of righting reflex; LORR). Both shared and strain-specific long-term consequences of adolescent alcohol exposure were found. Most notably, we found a strain-specific alcohol-induced increase in sensitivity to nicotine's hypothermic effects during adulthood in the DBA/2J strain but not in the C57BL/6J strain. Conversely, both strains demonstrated a robust increased latency to LORR during adulthood after adolescent alcohol exposure. Thus, we observed strain-dependent cross-sensitization to nicotine and strain-independent tolerance to alcohol due to adolescent alcohol exposure. Several strain and sex differences independent of adolescent alcohol treatment were also observed. These include increased sensitivity to nicotine-induced hypothermia in the C57BL/6J strain relative to the DBA/2J strain, in addition to DBA/2J mice showing more anxiety-like behaviors in the elevated plus maze relative to the C57BL/6J strain. Overall, these results suggest that adolescent alcohol exposure results in altered adult sensitivity to nicotine and alcohol with some phenotypes mediated by genetic background.

Antismoking agents do not contribute synergistically to semaglutide's ability to reduce alcohol intake in rats.

Preclinical studies have identified glucagon-like peptide-1 receptor (GLP-1R) agonists, and the antismoking agents varenicline and bupropion as tentative agents for treatment of alcohol use disorder (AUD). Combining different medications is a recent approach that has gained attention regarding heterogenous and difficult-to-treat diseases, like AUD. Successfully, this approach has been tested for the combination of varenicline and bupropion as it prevents relapse to alcohol drinking in rats. However, studies assessing the effects of the combination of semaglutide, an FDA-approved GLP-1R agonist for diabetes type II, and varenicline or bupropion to reduce alcohol intake in male and female rats remains to be conducted. Another approach to influence treatment outcome is to combine a medication with feeding interventions like high fat diet (HFD). While HFD reduces alcohol intake, the ability of the combination of HFD and semaglutide to alter alcohol drinking is unknown and thus the subject for a pilot study. Therefore, three intermittent alcohol drinking experiments were conducted to elucidate the effectiveness of these treatment combinations. We show that semaglutide, bupropion or HFD reduces alcohol intake in male as well as female rats. While various studies reveal beneficial effects of combinatorial pharmacotherapies for the treatment of AUD, we herein do not report any additive effects on alcohol intake by adding either varenicline or bupropion to semaglutide treatment. Neither does HFD exposure alter the ability of semaglutide to reduce alcohol intake. Although no additive effects by the combinatorial treatments are found, these findings collectively provide insight into possible monotherapeutical treatments for AUD.

N-oleoyl glycine and N-oleoyl alanine attenuate alcohol self-administration and preference in mice

The endocannabinoid system (ECS) plays a key modulatory role during synaptic plasticity and homeostatic processes in the brain and has an important role in the neurobiological processes underlying drug addiction. We have previously shown that an elevated ECS response to psychostimulant (cocaine) is involved in regulating the development and expression of cocaine-conditioned reward and sensitization. We therefore hypothesized that drug-induced elevation in endocannabinoids (eCBs) and/or eCB-like molecules (eCB-Ls) may represent a protective mechanism against drug insult, and boosting their levels exogenously may strengthen their neuroprotective effects. Here, we determine the involvement of ECS in alcohol addiction. We first measured the eCBs and eCB-Ls levels in different brain reward system regions following chronic alcohol self-administration using LC–MS. We have found that following chronic intermittent alcohol consumption, N-oleoyl glycine (OlGly) levels were significantly elevated in the prefrontal cortex (PFC), and N-oleoyl alanine (OlAla) was significantly elevated in the PFC, nucleus accumbens (NAc) and ventral tegmental area (VTA) in a region-specific manner. We next tested whether exogenous administration of OlGly or OlAla would attenuate alcohol consumption and preference. We found that systemic administration of OlGly or OlAla (60 mg/kg, intraperitoneal) during intermittent alcohol consumption significantly reduced alcohol intake and preference without affecting the hedonic state. These findings suggest that the ECS negatively regulates alcohol consumption and boosting selective eCBs exogenously has beneficial effects against alcohol consumption and potentially in preventing relapse.