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For many years, research from around the world has suggested that the neuroactive steroid (3α,5α)‐3‐hydroxypregnan‐20‐one (allopregnanolone or 3α,5α‐THP) may have therapeutic potential for treatment of various symptoms of alcohol use disorders (AUDs). In this critical review, we systematically address all the evidence that supports such a suggestion, delineate the etiologies of AUDs that are addressed by treatment with allopregnanolone or its precursor pregnenolone, and the rationale for treatment of various components of the disease based on basic science and clinical evidence. This review presents a theoretical framework for understanding how endogenous steroids that regulate the effects of stress, alcohol, and the innate immune system could play a key role in both the prevention and the treatment of AUDs. We further discuss cautions and limitations of allopregnanolone or pregnenolone therapy with suggestions regarding the management of risk and the potential for helping millions who suffer from AUDs. [ABSTRACT FROM AUTHOR]

Background: Binge alcohol drinking has been characterized as a key feature of alcoholism. The drinking‐in‐the‐dark (DID) preclinical model, a procedure that promotes high levels of ethanol (EtOH) intake in short periods of time, has been extensively used to investigate neuropharmacological and genetic determinants of binge‐like EtOH consumption. Using DID methodology, alcohol‐preferring strains of mice such as C57BL/6J (B6) mice consume enough EtOH to achieve blood concentrations (≥1.0 mg/ml) associated with behavioral intoxication (i.e., motor incoordination). DID procedures typically involve the use of socially isolated animals (single‐housed prior to and during the experiment). Previous research indicates that stress associated with social isolation can induce anxiety‐like behavior and promote increases in EtOH intake. The present study investigates the role of housing conditions in anxiety‐like behavior and binge‐like EtOH intake using a DID procedure. Methods: Male and female B6 mice were isolated or pair‐housed for a period of 6 weeks prior to evaluation of anxiety‐like (elevated plus maze, light and dark box, open field) and drinking (water, 10% sucrose, 10 to 30% EtOH) behavior. In order to measure intake, a variation of the standard DID procedure using a removable, transparent, and perforated plastic barrier strip (designed to temporarily divide the cage in 2) was introduced. This allowed for individual intake records (2‐hour test) of isolated and socially housed animals. Results: Increased anxiety‐like behavior and reduced sucrose consumption were found in isolated mice. The effects of housing conditions on EtOH intake were sex‐ and concentration‐dependent. In male mice, isolation increased 20 and 30% EtOH intake. In females, however, an increased intake of EtOH (30%) was found in socialized animals. No effects of housing or sex were found at EtOH 10%. Conclusions: Together with previous literature, the present study suggests that social isolation can promote anxiety‐associated behavior and produce sex‐dependent changes in binge‐like EtOH consumption. [ABSTRACT FROM AUTHOR]

Background: Adolescence is a critical period for neural development, and alcohol exposure during adolescence can lead to an elevated risk for health consequences as well as alcohol use disorders. Clinical and experimental data suggest that chronic alcohol exposure may produce immunomodulatory effects that can lead to the activation of pro‐inflammatory cytokine pathways as well as microglial markers. The present study evaluated, in brain and blood, the effects of adolescent alcohol exposure and withdrawal on microglia and on the most representative pro‐ and anti‐inflammatory cytokines and major chemokines that can contribute to the establishing of a neuroinflammatory environment. Methods: Wistar rats (males, n = 96) were exposed to ethanol (EtOH) vapors, or air control, for 5 weeks over adolescence (PD22‐PD58). Brains and blood samples were collected at 3 time points: (i) after 35 days of vapor/air exposure (PD58); (ii) after 1 day of withdrawal (PD59), and (iii) 28 days after withdrawal (PD86). The ionized calcium‐binding adapter molecule 1 (Iba‐1) was used to index microglial activation, and cytokine/chemokine responses were analyzed using magnetic bead panels. Results: After 35 days of adolescent vapor exposure, a significant increase in Iba‐1 immunoreactivity was seen in amygdala, frontal cortex, hippocampus, and substantia nigra. However, Iba‐1 density returned to control levels at both 1 day and 28 days of withdrawal except in the hippocampus where Iba‐1 density was significantly lower than controls. In serum, adolescent EtOH exposure induced a reduction in IL‐13 and an increase in fractalkine at day 35. After 1 day of withdrawal, IL‐18 was reduced, and IP‐10 was elevated, whereas both IP‐10 and IL‐10 were elevated at 28 days following withdrawal. In the frontal cortex, adolescent EtOH exposure induced an increase in IL‐1β at day 35, and 28 days of withdrawal, and IL‐10 was increased after 28 days of withdrawal. Conclusion: These data demonstrate that EtOH exposure during adolescence produces significant microglial activation; however, inflammatory markers seen in the blood appear to differ from those observed in the brain. [ABSTRACT FROM AUTHOR]

Background: Ethanol (EtOH), one of the most widely consumed substances of abuse, can induce brain damage and neurodegeneration. EtOH is centrally metabolized into acetaldehyde, which has been shown to be responsible for some of the neurophysiological and cellular effects of EtOH. Although some of the consequences of chronic EtOH administration on cell oxidative status have been described, the mechanisms by which acute EtOH administration affects the brain's cellular oxidative status and the role of acetaldehyde remain to be elucidated in detail. Methods: Swiss CD‐I mice were pretreated with the acetaldehyde‐sequestering agent d‐penicillamine (DP; 75 mg/kg, i.p.) or the antioxidant lipoic acid (LA; 50 mg/kg, i.p.) 30 minutes before EtOH (2.5 g/kg, i.p.) administration. Animals were sacrificed 30 minutes after EtOH injection. Glutathione peroxidase (GPx) mRNA levels; GPx and glutathione reductase (GR) enzymatic activities; reduced glutathione (GSH), glutathione disulfide (GSSG), glutamate, g‐L‐glutamyl‐L‐cysteine (Glut‐Cys), and malondialdehyde (MDA) concentrations; and protein carbonyl group (CG) content were determined in whole‐brain samples. Results: Acute EtOH administration enhanced GPx activity and the GSH/GSSG ratio, while it decreased GR activity and GSSG concentration. Pretreatment with DP or LA only prevented GPx activity changes induced by EtOH. Conclusions: Altogether, these results show the capacity of a single dose of EtOH to unbalance cellular oxidative homeostasis. [ABSTRACT FROM AUTHOR]

Background: Evidence supports a role for the circadian system in alcohol use disorders, but the impact of adolescent alcohol exposure on circadian timing later in life is unknown. Acute ethanol (EtOH) attenuates circadian photic phase‐resetting in adult, but not adolescent, rodents. However, nearly all studies have focused on males and it is unknown whether this adolescent‐typical insensitivity to EtOH persists into adulthood after adolescent drinking. Methods: Circadian activity was monitored in C57BL/6J mice receiving adolescent intermittent EtOH (AIE) exposure (15% EtOH and water every other day throughout adolescence) or water alone followed by 24 days wherein EtOH was not available (washout). Mice then received a challenge dose of EtOH (1.5 g/kg, intraperitoneal) or saline 15 minutes prior to a 30‐minute phase‐delaying light pulse and then were released into constant darkness (DD). To control for possible phase‐shifting by EtOH challenge alone, a separate group of mice underwent AIE exposure (or water‐only) and washout and then received an EtOH or saline injection, but did not receive a light pulse prior to DD. Results: Striking sex differences in nearly all measures of circadian photic entrainment were observed during adolescence but AIE effects were subtle and few. Only EtOH‐naïve adult male mice showed attenuated photic phase‐shifts with EtOH challenge, while all other groups showed normal phase‐resetting responses to light. AIE‐exposed females showed a persistent delay in activity offset. Conclusions: Adult male AIE‐exposed mice retained adolescent‐like insensitivity to EtOH‐induced suppression of photic phase‐resetting, suggesting AIE‐induced "lock‐in" of an adolescent behavioral phenotype. Adult AIE‐exposed females showed delayed initiation of the rest phase. Our results also indicate that intermittent EtOH drinking has subtle effects on circadian activity in mice during adolescence that differ from previously reported effects on adult males. The observed sex differences in circadian activity, EtOH consumption and preference, and responses to EtOH challenge merit future mechanistic study. Differential effects of adolescent drinking on circadian rhythms in adult mice. A) Adult female mice showed persistent delays in activity offset after exposure to adolescent intermittent ethanol (AIE), perhaps reflecting increased latency to sleep. B) Adult male mice with prior AIE exposure showed persistent insensitivity to acute ethanol‐induced attenuation of circadian phaseresetting to light. These data suggest that adolescent drinking affects circadian rhythms differently between the sexes, and may ultimately play a sex‐dependent role in motivation to drink in adulthood. [ABSTRACT FROM AUTHOR]

Background Ethanol (EtOH)-evoked oxidative stress, which contributes to myocardial dysfunction in proestrus rats, is mediated by increases in NADPH oxidase (Nox) activity, malondialdehyde ( MDA), and ERK1/2 phosphorylation. Whether these biochemical responses, which are triggered by alcohol-derived acetaldehyde in noncardiac tissues, occur in proestrus rats' hearts remains unknown. Therefore, we elucidated the roles of alcohol dehydrogenase ( ADH), cytochrome P4502E1 ( CYP2E1), and catalase, which catalyze alcohol oxidation to acetaldehyde, in these alcohol-evoked biochemical and hemodynamic responses in proestrus rats. Methods Conscious proestrus rats prepared for measurements of left ventricular ( LV) function and blood pressure ( BP) received EtOH (1.5 g/kg, intravenous [i.v.] infusion over 30 minutes) or saline 30 minutes after an ADH and CYP2E1 inhibitor, 4-methylpyrazole (4-MP) (82 mg/kg, intraperitoneal), a catalase inhibitor, 3- AT (0.5 g/kg, i.v.), their combination, or vehicle. LV function and BP were monitored for additional 60 minutes after EtOH or saline infusion before collecting the hearts for ex vivo measurements of LV reactive oxygen species ( ROS), Nox activity, MDA, and ERK1/2 phosphorylation. Results EtOH reduced LV function (d P/d tmax and LV developed pressure) and BP, and increased cardiac Nox activity, ROS and MDA levels, and ERK1/2 phosphorylation. Either inhibitor partially, and their combination significantly, attenuated these responses despite the substantially higher blood EtOH level, and the increased cardiac oxidative stress and reduced BP caused by 3- AT alone or with 4- MP. The inhibitors reduced cardiac MDA level and reversed EtOH effect on cardiac and plasma MDA. Conclusions EtOH oxidative metabolism plays a pivotal role in the EtOH-evoked LV oxidative stress and dysfunction in proestrus rats. Notably, catalase inhibition (3- AT) caused cardiac oxidative stress and hypotension. [ABSTRACT FROM AUTHOR]

Background In our companion article, we examined the role of MyD88-dependent signaling in ethanol (EtOH) consumption in mice lacking key components of this inflammatory pathway and observed differential effects on drinking. Here, we studied the role of these same signaling components in the acute sedative, intoxicating, and physiological effects of EtOH. Toll-like receptor 4 (TLR4) has been reported to strongly reduce the duration of EtOH-induced sedation, although most studies do not support its direct involvement in EtOH consumption. We examined TLR4 and other MyD88 pathway molecules to determine signaling specificity in acute EtOH-related behaviors. We also studied other GABAergic sedatives to gauge the EtOH specificity and potential role for GABA in EtOH's sedative and intoxicating effects in the mutant mice. Methods Loss of righting reflex ( LORR) and recovery from motor incoordination were studied following acute injection of EtOH or other sedative drugs in male and female control C57 BL/6J mice versus mice lacking CD14, TLR2, TLR4 (C57 BL/10ScN), or MyD88. We also examined EtOH-induced hypothermia and blood EtOH clearance in these mice. Results Male and female mice lacking TLR4 or MyD88 showed reduced duration of EtOH-induced LORR and faster recovery from EtOH-induced motor incoordination in the rotarod test. MyD88 knockout mice had slightly faster recovery from EtOH-induced hypothermia compared to control mice. None of the mutants differed from control mice in the rate of blood EtOH clearance. All of the mutants showed similar decreases in the duration of gaboxadol-induced LORR, but only mice lacking TLR4 were less sensitive to the sedative effects of pentobarbital. Faster recovery from diazepam-induced motor impairment was observed in CD14, TLR4, and MyD88 null mice of both sexes. Conclusions TLR4 and MyD88 were key mediators of the sedative and intoxicating effects of EtOH and GABAergic sedatives, indicating a strong influence of TLR4-MyD88 signaling on GABAergic function. Despite the involvement of TLR4 in EtOH's acute behaviors, it did not regulate EtOH consumption in any drinking model as shown in our companion article. Collectively, our studies demonstrate differential effects of TLR-MyD88 components in the acute versus chronic actions of EtOH. [ABSTRACT FROM AUTHOR]

Background Molecular and behavioral studies support a role for innate immune proinflammatory pathways in mediating the effects of alcohol. Increased levels of Toll-like receptors (TLRs) have been observed in animal models of alcohol consumption and in human alcoholics, and many of these TLRs signal via the MyD88-dependent pathway. We hypothesized that this pathway is involved in alcohol drinking and examined some of its key signaling components. Methods Different ethanol (EtOH)-drinking paradigms were studied in male and female control C57BL/6J mice versus mice lacking CD14, TLR2, TLR4 (C57BL/10ScN), or MyD88. We studied continuous and intermittent access 2-bottle choice (2BC) and 1-bottle and 2BC drinking-in-the-dark (DID) tests as well as preference for saccharin, quinine, and NaCl. Results In the 2BC continuous access test, EtOH intake decreased in male TLR2 knockout (KO) mice, and we previously reported reduced 2BC drinking in male and female CD14 KO mice. In the intermittent access 2BC test, EtOH intake decreased in CD14 KO male and female mice, whereas drinking increased in MyD88 KO male mice. In the 2BC-DID test, EtOH drinking decreased in male and female mice lacking TLR2, whereas drinking increased in MyD88 KO male mice. In the 1-bottle DID test, EtOH intake decreased in female TLR2 KO mice. TLR2 KO and CD14 KO mice did not differ in saccharin preference but showed reduced preference for NaCl. MyD88 KO mice showed a slight reduction in preference for saccharin. Conclusions Deletion of key components of the MyD88-dependent pathway produced differential effects on EtOH intake by decreasing (TLR2 KO and CD14 KO) or increasing (MyD88 KO) drinking, while deletion of TLR4 had no effect. Some of the drinking effects depended on the sex of the mice and/or the EtOH-drinking model. [ABSTRACT FROM AUTHOR]

Background Growing evidence supports a central role for the circadian system in alcohol use disorders, but few studies have examined this relationship during adolescence. In mammals, circadian rhythms are regulated by the suprachiasmatic nucleus, a biological clock whose timing is synchronized (reset) to the environment primarily by light (photic) input. Alcohol (ethanol [EtOH]) disrupts circadian timing in part by attenuating photic phase-resetting responses in adult rodents. However, circadian rhythms change throughout life and it is not yet known whether EtOH has similar effects on circadian regulation during adolescence. Methods General circadian locomotor activity was monitored in male C57BL6/J mice beginning in adolescence (P27) or adulthood (P61) in a 12-hour light, 12-hour dark photocycle for ~2 weeks to establish baseline circadian activity measures. On the day of the experiment, mice received an acute injection of EtOH (1.5 g/kg, i.p.) or equal volume saline 15 minutes prior to a 30-minute light pulse at Zeitgeber Time 14 (2 hours into the dark phase) and then were released into constant darkness (DD) for ~2 weeks to assess phase-resetting responses. Control mice of each age-group received injections but no light pulse prior to DD. Results While adults showed the expected decrease in photic phase-delays induced by acute EtOH, this effect was absent in adolescent mice. Adolescents also showed baseline differences in circadian rhythmicity compared to adults, including advanced photocycle entrainment, larger photic phase-delays, a shorter free-running (endogenous) circadian period, and greater circadian rhythm amplitude. Conclusions Collectively, our results indicate that adolescent mice are less sensitive to the effect of EtOH on circadian photic phase-resetting and that their daily activity rhythms are markedly different than those of adults. [ABSTRACT FROM AUTHOR]

The innate immune response in the central nervous system ( CNS) participates in both synaptic plasticity and neural damage. Emerging evidence from human and animal studies supports the role of the neuroimmune system response in many actions of ethanol (EtOH) on the CNS. Research studies have shown that alcohol stimulates brain immune cells, microglia, and astrocytes, by activating innate immune receptors Toll-like receptors (TLRs) and NOD-like receptors (inflammasome NLRs) triggering signaling pathways, which culminate in the production of pro-inflammatory cytokines and chemokines that lead to neuroinflammation. This review focuses on evidence that indicates the participation of TLRs and the inflammasome NLRs signaling response in many effects of EtOH on the CNS, such as neuroinflammation associated with brain damage, cognitive and behavioral dysfunction, and adolescent brain development alterations. It also reviews findings that indicate the role of TLR4-dependent signaling immune molecules in alcohol consumption, reward, and addiction. The research data suggest that overactivation of TLR4 or NLRs increases pro-inflammatory cytokines and mediators to cause neural damage in the cerebral cortex and hippocampus, while modest TLR4 activation, along with the generation of certain cytokines and chemokines in specific brain areas (e.g., amygdala, ventral tegmental area), modulate neurotransmission, alcohol drinking, and alcohol rewards. Elimination of TLR4 and NLRP3 abolishes many neuroimmune effects of EtOH. Despite much progress being made in this area, there are some research gaps and unanswered questions that this review discusses. Finally, potential therapies that target neuroimmune pathways to treat neuropathological and behavioral consequences of alcohol abuse are also evaluated. [ABSTRACT FROM AUTHOR]

Background Cyclic AMP-dependent protein kinase A ( PKA) signaling is a key target for the action of alcohol and may therefore play a role in the pathophysiology of alcohol withdrawal seizures ( AWSs). Here, we investigated the role of PKA activity with respect to increased seizure susceptibility in rats that were subjected to alcohol withdrawal. Methods Adult male Sprague Dawley rats received 3 daily doses of ethanol (EtOH) (or vehicle) for 4 consecutive days. Rats were then tested for susceptibility to acoustically evoked AWSs 3, 24, and 48 hours after the last alcohol dose. In separate experiments, the inferior colliculus ( IC) was collected at these same time points from rats subjected to alcohol withdrawal and control rats following alcohol withdrawal. PKA activity, catalytic C α ( PKAC α) protein, regulatory RII α ( PKARII α) protein, and RII β ( PKARII β) protein were measured in the IC. Lastly, in situ pharmacological studies were performed to evaluate whether inhibiting PKA activity in the IC suppressed AWSs. Results In the EtOH-treated group, AWSs were observed at the 24-hour time point, but not at the 3-hour or 48-hour time points. In the IC, PKA activity was significantly higher both 3 hours (i.e., before AWS susceptibility) and 24 hours after the last alcohol dose (when AWS susceptibility peaked) than in control rats. Consistent with these findings, protein levels of the PKAC α subunit were significantly increased in the IC both 3 and 24 hours after the last alcohol dose. Lastly, in situ inhibition of PKA activity within the IC suppressed AWSs. Conclusions The increase in PKA activity and PKAC α protein expression in the IC preceded the occurrence of AWSs, and inhibiting PKA activity within the IC suppressed acoustically evoked AWSs. Together, these findings suggest that altered PKA activity plays a key role in the pathogenesis of AWSs. [ABSTRACT FROM AUTHOR]

Background Novelty-seeking behavior is related to the reward system in the brain and can predict the potential for addiction. Alcohol use is prevalent in HIV-1-infected patients and adversely affects antiretroviral medication. The difference in vulnerability to alcohol addiction between HIV-1-infected and noninfected populations has not been fully investigated. This study was designed to determine whether HIV-1 proteins alter the effects of ethanol (EtOH) on novelty-seeking behavior using the HIV-1 transgenic ( HIV-1Tg) rat as the study model and to examine the molecular mechanisms responsible for this behavior. Methods Both HIV-1Tg and F344 control rats were tested for baseline novelty-seeking behavior, then received either EtOH (1 g/kg) at a concentration of 20% v/v or saline treatment for 13 days, and then were retested for novelty seeking. Quantitative real-time polymerase chain reaction was conducted to examine the differences in expression of 65 genes implicated in novelty seeking and alcohol addiction between strains and treatment groups. Results The HIV-1 proteins significantly enhanced baseline novelty-seeking behaviors in both the hole-board and open-field tests. Chronic EtOH treatment significantly increased baseline novelty-seeking behavior in both strains, but the effects of EtOH appeared to be more robust and prominent in HIV-1Tg rats. Strain-specific patterns of altered gene expression were observed for dopaminergic, cholinergic, and glutamatergic signaling in the nucleus accumbens, suggesting the effects of HIV-1 proteins on the brain's reward system. Chronic EtOH treatment was shown to greatly modulate the effects of HIV-1 proteins in these neurotransmitter systems. Conclusions Taken together, our findings indicate that HIV-1 proteins could modify novelty-seeking behavior at the gene expression level, and EtOH treatment may enhance this behavior in both strains but to a greater extent in HIV-1Tg rats. [ABSTRACT FROM AUTHOR]

Background There is controversy regarding the active agent responsible for alcohol addiction. The theory that ethanol (EtOH) itself was the agent in alcohol drinking behavior was widely accepted until acetaldehyde (AcH) was found in the brain. The importance of AcH formation in the brain is still subject to speculation due to the lack of a method to accurately assay the AcH levels directly. A highly sensitive gas chromatography mass spectrometry (GC-MS) method to reliably determine AcH concentration with certainty is needed to address whether neural AcH is indeed responsible for increased alcohol consumption. Methods A headspace gas chromatograph coupled to selected-ion monitoring MS was utilized to develop a quantitative assay for AcH and EtOH. Our GC- MS approach was carried out using a Bruker Scion 436- GC SQ MS. Results Our approach yields limits of detection of AcH in the nanomolar range and limits of quantification in the low micromolar range. Our linear calibration includes 5 concentrations with a least-square regression greater than 0.99 for both AcH and EtOH. Tissue analyses using this method revealed the capacity to quantify EtOH and AcH in blood, brain, and liver tissue from mice. Conclusions By allowing quantification of very low concentrations, this method may be used to examine the formation of EtOH metabolites, specifically AcH, in murine brain tissue in alcohol research. [ABSTRACT FROM AUTHOR]

Background A number of studies have shown that acetaldehyde synthesized in the brain is necessary to induce ethanol (EtOH) reinforcement in naïve animals ( acquisition phase). However, after chronic intake is achieved ( maintenance phase), EtOH intake becomes independent of acetaldehyde generation or its levels. Glutamate has been reported to be associated with the maintenance of chronic EtOH intake. The levels of brain extracellular glutamate are modulated by 2 glial processes: glutamate reabsorption via an Na+-glutamate transporter ( GLT1) and a cystine-glutamate exchanger. Chronic EtOH intake lowers GLT1 levels and increases extracellular glutamate. The administration of N-acetyl cysteine ( NAC), a precursor of cystine, has been shown to reduce the relapse of several drugs of abuse, while NAC has not been tested on chronic EtOH intake or on EtOH's influence on the motivation for another drug. These were investigated in the present study. Methods (i) Rats bred for their high EtOH intake were allowed access to 10% EtOH and water up to 87 days. NAC was administered (30 and 60 mg/kg daily, intraperitoneally) for 14 consecutive days, either during the acquisition phase or the maintenance phase of EtOH drinking. (ii) In additional experiments, rats were allowed EtOH (10%) and water access for 61 days, after which EtOH was replaced by saccharin (0.3%) to determine both if chronic EtOH consumption influences saccharin intake and whether NAC modifies the post chronic EtOH saccharin intake. Results NAC did not influence the acquisition ('first hit') of chronic EtOH intake, but greatly inhibited (60 to 70%; p < 0.0001) EtOH intake when NAC was administered to animals that were consuming EtOH chronically. NAC did not influence saccharin intake in naïve animals. In animals that had consumed EtOH chronically and were thereafter offered a saccharin solution (0.3%), saccharin intake increased over 100% versus that of EtOH-untreated animals, an effect that was fully suppressed by NAC. Conclusions N-acetyl cysteine, a drug approved for use in humans, markedly reduces chronic EtOH intake and abolishes the increased intake of saccharin stimulated by chronic EtOH drinking. [ABSTRACT FROM AUTHOR]

Background Ethanol is widely known for its depressant effects; however, the underlying neurobiological mechanisms are not clear. Calcium-activated anion channels ( CAACs) contribute to extracellular chloride levels and thus may be involved in regulating inhibitory mechanisms within the central nervous system. Therefore, we hypothesized that CAACs influence ethanol behavioral sensitivity by altering CAAC expression. Methods We assessed the role of CAACs in ethanol-induced loss of righting reflex ( LORR) and locomotor activity using intracerebroventricular infusions of several nonselective CAAC blockers. CAAC expression was determined after ethanol exposure. Results Ethanol-induced LORR (4.0 g/kg, intraperitoneally [i.p.]) was significantly attenuated by all 4 CAAC blockers. Blocking CAACs did not impact ethanol's low-dose (1.5 g/kg, i.p.) locomotor-impairing effects. Biochemical analysis of CAAC protein expression revealed that cortical Bestrophin1 (Best1) and Tweety1 levels were reduced as early as 30 minutes following a single ethanol injection (3.5 g/kg, intraperitoneally [i.p.]) and remained decreased 24 hours later in P2 fractions. Cortical Best1 levels were also reduced following 1.5 g/kg. However, CAAC expression was unaltered in the striatum following a single ethanol exposure. Ethanol did not affect Tweety2 levels in either brain region. Conclusions These results suggest that CAACs are a major target of ethanol in vivo , and the regulation of these channels contributes to select behavioral actions of ethanol. [ABSTRACT FROM AUTHOR]

Background The lung has a highly regulated system of innate immunity to protect itself from inhaled microbes and toxins. The first line of defense is mucociliary clearance, but if invaders overcome this, inflammatory pathways are activated. Toll-like receptors ( TLRs) are expressed on the airway epithelium. Their signaling initiates the inflammatory cascade and leads to production of inflammatory cytokines such as interleukin (IL)-6 and IL-8. We hypothesized that airway epithelial insults, including heavy alcohol intake or smoking, would alter the expression of TLRs on the airway epithelium. Methods Bronchoscopy with bronchoalveolar lavage and brushings of the airway epithelium was performed in otherwise healthy subjects who had normal chest radiographs and spirometry. A history of alcohol use disorders ( AUDs) was ascertained using the Alcohol Use Disorders Identification Test ( AUDIT), and a history of cigarette smoking was also obtained. Age, gender, and nutritional status in all groups were similar. We used real-time polymerase chain reaction (PCR) to quantitate TLR1 to 9 and enzyme-linked immune assay to measure tumor necrosis factor- α, IL-6, and IL-8. Results Airway brushings were obtained from 26 nonsmoking/non- AUD subjects, 28 smoking/non- AUD subjects, 36 smoking/ AUD subjects, and 17 nonsmoking/ AUD subjects. We found that TLR2 is up-regulated in AUD subjects, compared to nonsmoking/non- AUD subjects, and correlated with their AUDIT scores. We also measured a decrease in TLR4 expression in AUD subjects that correlated with AUDIT score. IL-6 and IL-8 were also increased in bronchial washings from AUD subjects. Conclusions We have previously demonstrated in normal human bronchial epithelial cells that in vitro alcohol exposure up-regulates TLR2 through a NO/ cGMP/ PKG-dependent pathway, resulting in up-regulation of inflammatory cytokine production after Gram-positive bacterial product stimulation. Our current translational study confirms that TLR2 is also up-regulated in humans with AUDs. [ABSTRACT FROM AUTHOR]

This review analyzes literature that describes the behavioral effects of 2 metabolites of ethanol (EtOH): acetaldehyde and salsolinol (a condensation product of acetaldehyde and dopamine) generated in the brain. These metabolites are self-administered into specific brain areas by animals, showing strong reinforcing effects. A wealth of evidence shows that EtOH, a drug consumed to attain millimolar concentrations, generates brain metabolites that are reinforcing at micromolar and nanomolar concentrations. Salsolinol administration leads to marked increases in voluntary EtOH intake, an effect inhibited by mu-opioid receptor blockers. In animals that have ingested EtOH chronically, the maintenance of alcohol intake is no longer influenced by EtOH metabolites, as intake is taken over by other brain systems. However, after EtOH withdrawal brain acetaldehyde has a major role in promoting binge-like drinking in the condition known as the 'alcohol deprivation effect'; a condition seen in animals that have ingested alcohol chronically, are deprived of EtOH for extended periods, and are allowed EtOH re-access. The review also analyzes the behavioral effects of acetate, a metabolite that enters the brain and is responsible for motor incoordination at low doses of EtOH. Also discussed are the paradoxical effects of systemic acetaldehyde. Overall, evidence strongly suggests that brain-generated EtOH metabolites play a major role in the early ('first-hit') development of alcohol reinforcement and in the generation of relapse-like drinking. [ABSTRACT FROM AUTHOR]