Moderate Dose Of Ethanol Research Articles

Reduced acute functional tolerance and enhanced preference for ethanol in Caenorhabditis elegans exposed to lead during development: Potential role of alcohol dehydrogenase

Despite its relative simplicity, the invertebrate Caenorhabditis elegans (C. elegans) has become a powerful tool to evaluate toxicity. Lead (Pb) persistence in the environment and its distinctive characteristic as a neurodevelopmental toxicant determine the potential effects of this metal against challenging events later in life. Additionally, among other psychoactive substances, low to moderate ethanol (EtOH) doses have been pointed out to induce behaviors such as acute functional tolerance (AFT) and drug-induced chemotaxis. In the present study, we aimed to study the impact of early-life Pb exposure on EtOH-induced motivational and stimulant effects in C. elegans by assessing the preference for EtOH and the participation of alcohol dehydrogenase (ADH, sorbitol dehydrogenase -SODH in worms) in the AFT response. Thus, N2 (wild type) and RB2114 (sod-1 −/−) strains developmentally exposed to 24 μM Pb were evaluated in their AFT to 200 mM EtOH alone and in combination with acetaldehyde (ACD). We ascribed the enhanced EtOH-induced AFT observed in the N2 Pb-exposed animals to a reduced ADH functionality as evaluated by both, ADH activity determination and the allyl alcohol test, which altogether suggest excess EtOH accumulation rather than low ACD formation in these animals. Moreover, the Pb-induced preference for EtOH indicates enhanced motivational effects of this drug as a consequence of early-life exposure to Pb, results that resemble our previous reports in rodents and provide a close association between EtOH stimulant and motivational effects in these animals.

Incorporating ventilatory activity into a novel tank test for evaluating drug effects on zebrafish

The effects of ethanol and caffeine exposure on zebrafish, Danio rerio, were investigated using a combination of measurements of behavioral and physiologic responses in a novel tank situation. Ventilation activity as a physiologic measure was measured remotely by monitoring ventilation-related bioelectric signals from freely moving zebrafish in the test tank. The directions of the behavioral responses, except for outer area preference, were substantially the same in both ethanol- and caffeine-treated fish and qualitatively indistinguishable, suggesting that relying solely on behavioral measures may lead to inappropriate interpretation of drug effects when depending on limited behavioral parameters. By incorporating ventilation activity–related physiologic measures into the quantification of drug effects in novel tank tests, more-accurate evaluations of differences in the effects of moderate doses of anxiolytic ethanol and anxiogenic caffeine were possible. Here, we propose that combining physiologic measures such as ventilation rate and its variability with behavioral measures makes it possible to characterize the effects of environmental challenges on zebrafish in a multi-dimensional and more-detailed manner.

Alcohol and Alcohol Combined with Texting: Evaluation of Driving Impairment Effects in a Closed-Course Section

Objective Examine the driving impairment effects of alcohol alone and of alcohol combined with texting. Methods Fifteen drivers (nine male, six female; mean age: 31.1 ± 6.9 years, range: 23 to 43 years) with similar drinking habit (i.e., social drinkers) completed a lap in a closed-course section in six different situations: (I) sober; (II) sober and while texting; (III) 30 minutes after ingesting a moderate dose of ethanol (0.50 g/kg); (IV) 30 minutes after drinking and while texting; (V) 60 minutes after drinking, (VI) 60 minutes after drinking and while texting. Driving performance was analyzed by means of maximum and mean speed, braking time and braking distance; and ability to control the car (i.e., evaluating if the drivers hit a traffic cone or exceeded the boundaries of the course). P values of < 0.05 were considered significant. Results Pre and post-alcohol consumption results show a significant increase concerning the drivers’ mean and maximum speed after drinking (p < 3.2x10−8). However, neither alcohol nor texting had significant effects on braking parameters (p > 0.05). Traffic cones were knocked down only in texting experiments. In addition, when using the cell phone drivers tended to reduce the speed, and to accelerate abruptly right after they finish texting. Conclusion Our findings strengthen the hypothesis that even moderate alcohol doses may significantly impair the driving performance. Additionally, alcohol and texting have complementary effects on driving impairment, and their combination represents a significant risk factor for crashes.

Alcohol binge drinking decreases brain glucose metabolism and functional connectivity in adolescent rats.

Alcohol misuse represents a serious health concern, especially during adolescence, with approximately 18% of high school students engaging in binge drinking. Despite widespread misuse of alcohol, its effects on how the brain functions is not fully understood. This study utilized a binge drinking model in adolescent rats to examine effects on brain function as measured by brain glucose metabolism (BGluM). Following an injection of [18 FDG] fluro-2-deoxy-D-glucose, rats had voluntary access to either water or various concentrations of ethanol to obtain the following targeted doses: water (no ethanol), low dose ethanol (0.29 ± 0.03g/kg), moderate dose ethanol (0.98 ± 0.05), and high dose ethanol (2.19 ± 0.23g/kg). Rats were subsequently scanned using positron emission tomography. All three doses of ethanol were found to decrease BGluM in the restrosplenial cortex, visual cortex, jaw region of the somatosensory cortex, and cerebellum. For both the LD and MD ethanol dose, decreased BGluM was seen in the superior colliculi. The MD ethanol dose also decreased BGluM in the subiculum, frontal association area, as well as the primary motor cortex. Lastly, the HD ethanol dose decreased BGluM in the hippocampus, thalamus, raphe nucleus, inferior colliculus, and the primary motor cortex. Similar decreases in the hippocampus were also seen in the LD group. Taken together, these results highlight the negative consequences of acute binge drinking on BGluM in many regions of the brain involved in sensory, motor, and cognitive processes. Future studies are needed to assess the long-term effects of alcohol binge drinking on brain function as well as its cessation.

Circulating corticosterone levels mediate the relationship between acute ethanol intoxication and markers of NF-κB activation in male rats

Binge drinking is a harmful pattern of alcohol use that is associated with a number of serious health problems. Of particular interest are the rapid alterations in neuroimmune gene expression and the concurrent activation of the hypothalamic-pituitary-adrenal (HPA) axis activation associated with high intensity drinking. Using a rat model of acute binge-like ethanol exposure, the present studies were designed to assess the role of corticosterone (CORT) in ethanol-induced neuroimmune gene expression changes, particularly those associated with the NFκB signaling pathway, including rapid induction of IL-6 and IκBα, and suppression of IL-1β and TNFα gene expression evident after administration of moderate to high doses of ethanol (1.5–3.5 g/kg ip) during intoxication (3 h post-injection). Experiment 1 tested whether inhibition of CORT synthesis with metyrapone and aminoglutethimide (100 mg/kg each, sc) would block ethanol-induced changes in neuroimmune gene expression. Results indicated that rapid alterations in IκBα, IL-1β, and TNFα expression were completely blocked by pretreatment with the glucocorticoid synthesis inhibitors, an effect that was reinstated by co-administration of exogenous CORT (3.75 mg/kg) in Experiment 2. Experiment 3 assessed whether these rapid alterations in neuroimmune gene expression would be evident when rats were challenged with a subthreshold dose of ethanol (1.5 g/kg) in combination with 2.5 mg/kg CORT, which showed limited evidence for additive effects of low-dose CORT combined with a moderate dose of ethanol. Acute inhibition of mineralocorticoid (spironolactone) or glucocorticoid (mifepristone) receptors, alone (Experiment 4) or combined (Experiment 5) had no effect on ethanol-induced changes in neuroimmune gene expression, presumably due to poor CNS penetrance of these drugs. Finally, Experiments 6 and 7 showed that dexamethasone (subcutaneous; a GR agonist) recapitulated effects of ethanol. Overall, we conclude that ethanol-induced CORT synthesis and release is responsible for suppression of IL-1β, TNFα, and induction of IκBα in the hippocampus through GR signaling. Interventions designed to curb these changes may reduce drinking, and subdue detrimental neuroimmune activation induced by ethanol.

The effect of rifampicin on the system of Toll-like receptors in the nucleus accumbens of the brain of long-term alcoholized rats during alcohol withdrawal

Nucleus accumbens (NAc) is the ventral part of the striatum of the brain; it is an important part of the mesolimbic pathway involved in the reward system that mediates the formation of various forms of addiction, in particular alcohol addiction. Neuroimaging data and in vitro studies indicate the development of a pronounced neurodegenerative process in the NAc, with long-term alcohol use, but the key mechanisms mediating this process remain unknown. In recent years, the attention of researchers has been focused on studying the system of Toll-like receptors (TLRs), the increased activity of which is clearly shown in the cerebral cortex and hippocampus during prolonged alcohol exposure, but there is a need to study the role of this system in other brain structures. In this study, we have shown that prolonged alcohol exposure (2 months) with moderate doses of ethanol (2 g/kg) promotes a pronounced increase in the expression of the Tlr4 gene and its endogenous ligand Hmgb1 in NAc during the period of alcohol withdrawal in rats. Injections of rifampicin (100 mg/kg) reduced the elevated expression level of Hmgb1, Tlr4, as well as pro-inflammatory cytokine genes (IL1β, IL6), while the administration of the drug increased the reduced level of mRNA of anti-inflammatory cytokines (IL10, IL11).

A novel murine model of multi-day moderate ethanol exposure reveals increased intestinal dysfunction and liver inflammation with age

BackgroundThere are currently > 600 million people over the age of 65 globally and this number is expected to double by the year 2050. Alcohol use among this population is on the rise, which is concerning as aging is associated with increased risk for a number of chronic illnesses. As most studies investigating the effects of alcohol have focused on young/middle-aged populations, there is a dearth of information regarding the consequences of alcohol use in older consumers. In addition, most murine ethanol models have concentrated on exposure to very high levels of ethanol, while the vast majority of elderly drinkers do not consume alcohol in excess; instead, they drink on average 2 alcoholic beverages a day, 3–4 days a week.MethodsWe designed a murine model of aging and moderate ethanol consumption to determine if the deleterious effects of alcohol on the gut-liver axis are exacerbated in aged, relative to younger, animals. Aged and young mice were exposed to a multi-day moderate exposure ethanol regimen for 4 weeks and changes in gut permeability along with intestinal tight junction protein and antimicrobial peptide gene expression were measured. In addition, hepatic inflammation was assessed by histological analysis, inflammatory gene expression and flow cytometric analysis of inflammatory infiltrate.ResultsOur results reveal that in aged, but not young mice, moderate ethanol exposure yielded significantly worsened intestinal permeability, including increased bacterial translocation from the gut, elevated serum iFABP and leakage of FITC-dextran from the gut. Interestingly, moderate ethanol exposure in young animals led to gut protective transcriptional changes in the ileum while this protective response was blunted in aged mice. Finally, moderate ethanol exposure in aged mice also resulted in marked inflammatory changes in the liver.ConclusionsThese results demonstrate that aged mice are more susceptible to ethanol-induced gut barrier dysfunction and liver inflammation, even at moderate doses of ethanol. This increased vulnerability to ethanol’s gastrointestinal effects has important implications for alcohol use in the aging population. Future studies will explore whether improving intestinal barrier function can reverse these age-related changes.

Maternal manipulation during late gestation (GDs 17-20) enhances ethanol consumption and promotes changes and opioid mRNA expression in infant rats

Fetal ethanol experience generates learning and memories capable to increase ethanol consummatory behaviors during infancy. Opioid system seems to be involved in mediating those alcohol-related behaviors. In this work, we proposed to study the impact of prenatal exposure to a moderate ethanol dose, upon ingestion of the drug and possible ethanol-induced molecular changes on opioid precursor peptides (POMC, Pro-enk and Pro-DYN) and receptors (MOR, DOR and KOR) mRNA expression, in hypothalamus. Pregnant rats received during gestational days (GDs) 17-20, a daily intragastric (i.g.) administration with 2g/kg ethanol or water. A third group of dams was left undisturbed during pregnancy (Unmanipulated group). Intake test was conducted at postnatal days (PDs) 14-15. Three groups of pups were performed: control (no intake test), water (vehicle) and 5% ethanol. At the end of intake test blood samples were taken to quantify blood ethanol concentrations (BECs) and hypothalamus sections were obtained to perform qRT-PRC assessment of opioid precursor peptides and receptors. The analysis of the consummatory responses (% of consumption) and pharmacokinetic profiles (BECs) suggested that maternal manipulation induced by i.g. intubations, during the last four days of gestation (whenever ethanol or water), are sufficient to induce infantile ethanol intake during infancy. Gene expression from the hypothalamus of unmanipulated group revealed that infantile ingestive experiences with ethanol can down-regulate expression of mRNA Pro-Dyn and up-regulate mRNA expression of MOR and KOR. Finally, MOR mRNA expression was attenuated by prenatal i.g. manipulation in pups exposed to 5% ethanol.

Effects of puerarin on spatial learning and memory function in mice with acute alcohol consumption: An evaluation based upon firing rate and oxygen saturation analysis.

Ethanol is associated with various medical comorbidities affecting the brain and central nervous system. The use of puerarin in treating alcohol-induced memory disorders is systematically evaluated in this study based upon an analysis of the firing rate and oxygen saturation (SO2). A multi-channel data acquisition system and near-infrared spectroscopy (NIRS) were combined to obtain the electroneurophysiological signals and SO2 in the hippocampus of mice from the Institute of Cancer Research (ICR) after ethanol injection. A T-maze test was performed to study the alteration of spatial memory function. Ethanol was administered intraperitoneally (i.p.) in 2 dosages (1.5 g/kg and 0.5 g/kg). To investigate the effects of puerarin against acute ethanol-induced memory impairment, the same parameters corresponding to electroneurophysiological signals, SO2 and behavior performance in mice were also recorded upon the supplementation of puerarin in 2 dosages (25 mg/kg and 50 mg/kg). An inhibited firing rate and decreased SO2 were found in mice treated with an ethanol dose of 1.5 g/kg, which resulted in a low correct choice rate in the T-maze test, while an opposite trend appeared in mice which had been administered a moderate ethanol dose (0.5 g/kg). The trend of SO2 was positively correlated with that of the firing rate. A decreased firing rate and SO2 were accompanied by a decrease in the correct choice rate. With the supplementation of puerarin, a significant increase in the mean firing rate and SO2, as well as an improved correct choice rate, can be found in mice injected with excessive ethanol. The electroneurophysiological signals and NIRS were combined for the first time to prove that an excessive intake of ethanol can inhibit the spatial learning and memory function of mice. The supplementation of puerarin can suppress these adverse effects induced by ethanol at a high dosage, as evidenced by the increased firing rate and SO2.

Prenatal ethanol exposure attenuates sensitivity to the aversive effects of ethanol in adolescence and increases adult preference for a 5% ethanol solution in males, but not females.

The present set of experiments investigated the effects of a moderate dose of ethanol (2g/kg; 20% v/v intragastrically) during late gestation (G17-20 [gestational day]) on ethanol-induced conditioned taste aversion (CTA) in adolescence, and on ethanol consumption during adolescence and early adulthood. In experiment 1, male and female Sprague-Dawley rats were given 30-min access to a sweetened "supersaccharin" (SS) solution or sodium chloride (NaCl), followed by an intraperitoneal injection of 20% ethanol (0, 1, 1.25, or 1.5g/kg) for three conditioning/test sessions. Among animals conditioned with SS, prenatally ethanol-exposed males exhibited attenuated ethanol-induced CTA relative to males prenatally gavaged with water or non-manipulated, whereas prenatal treatment had no effect on CTA in females. Among animals conditioned with NaCl, there were no exposure group differences in males, with modest evidence for attenuated CTA in prenatally ethanol-exposed females. In experiment 2, the effects of prenatal ethanol exposure on ethanol consumption in adolescents (P35±1 day [postnatal day]) and adults (P56-60) were explored. At the beginning of the dark cycle, pair-housed rats were given three bottles containing 0, 5, and 10% ethanol for 18h every other day (i.e., Monday, Wednesday, Friday) for 3 weeks. Relative to water controls, adult males prenatally exposed to ethanol showed greater preference and more intake (g/kg) of 5% ethanol, while showing lower intake of 10% ethanol. These intake and preference differences were not evident in adolescent males. Among females at both ages, ethanol-exposed animals showed lower preference and intake (g/kg) of 5% ethanol than their water-exposed controls. Thus, moderate ethanol exposure during late gestation produced a largely male-specific attenuation in the aversive effects of ethanol during adolescence that could contribute to later increases in preference and intake of a 5% ethanol solution, although this emergent effect was not evident in adolescence (or in females), but only manifested in adulthood.

Insomnia as a path to alcoholism: tolerance development and dose escalation.

To assess the risks associated with the use of alcohol as a "sleep aid," we evaluated tolerance development to pre-sleep ethanol's sedative-hypnotic effects, and subsequent ethanol dose escalation. Volunteers, 21-55 years old, with insomnia in otherwise good medical and psychiatric health and no history of alcoholism or drug abuse participated. In experiment 1 (n = 24) 0.0, 0.3, or 0.6 g/kg (n = 8 per dose) ethanol was administered before sleep and 8-hour nocturnal polysomnograms (NPSGs) were collected. In experiment 2, after six nights pretreatment with ethanol 0.45 g/kg (n = 6) versus placebo (n = 6), choice of pre-sleep ethanol or placebo was assessed over seven choice nights. The 0.6 g/kg ethanol dose increased total sleep time and stage 3-4 sleep on night 2, but these effects were lost by night 6 (p < .05). Six nights of ethanol pretreatment produced on the choice nights more self-administered ethanol refills than the placebo pretreatment (p < .03). These are the first data to explicitly show the risks associated with the use of alcohol as a "sleep aid" among people with insomnia. Initially, a moderate dose of ethanol improved NPSG sleep, which was lost by night 6. Tolerance was associated with enhanced self-administration of pre-sleep ethanol.

Brief ethanol exposure and stress-related factors disorganize neonatal breathing plasticity during the brain growth spurt period in the rat

The effects of early ethanol exposure upon neonatal respiratory plasticity have received progressive attention given a multifactorial perspective related with sudden infant death syndrome or hypoxia-associated syndromes. The present preclinical study was performed in 3-9-day-old pups, a stage in development characterized by a brain growth spurt that partially overlaps with the 3rd human gestational trimester. Breathing frequencies and apneas were examined in pups receiving vehicle or a relatively moderate ethanol dose (2.0g/kg) utilizing a whole body plethysmograph. The experimental design also considered possible associations between drug administration stress and exteroceptive cues (plethysmographic context or an artificial odor). Ethanol exposure progressively exerted a detrimental effect upon breathing frequencies. A test conducted at PD9 when pups were under the state of sobriety confirmed ethanol's detrimental effects upon respiratory plasticity (breathing depression). Pre-exposure to the drug also resulted in a highly disorganized respiratory response following a hypoxic event, i.e., heightened apneic episodes. Associative processes involving drug administration procedures and placement in the plethysmographic context also affected respiratory plasticity. Pups that experienced intragastric administrations in close temporal contiguity with such a context showed diminished hyperventilation during hypoxia. In a 2nd test conducted at PD9 while pups were intoxicated and undergoing hypoxia, an attenuated hyperventilatory response was observed. In this test, there were also indications that prior ethanol exposure depressed breathing frequencies during hypoxia and a recovery normoxia phase. As a whole, the results demonstrated that brief ethanol experience and stress-related factors significantly disorganize respiratory patterns as well as arousal responses linked to hypoxia in neonatal rats.

Ethanol Reversal of Oxycodone Tolerance in Dorsal Root Ganglia Neurons.

Oxycodone is a semisynthetic opioid compound that is widely prescribed, used, and abused today, and has a well-established role in shaping the current opioid epidemic. Previously, we have shown that tolerance develops to the antinociceptive and respiratory depressive effects of oxycodone in mice, and that a moderate dose of acute ethanol or a protein kinase C (PKC) inhibitor reversed that tolerance. To investigate further if tolerance was occurring through neuronal mechanisms, our aims for this study were to assess the effects of acute and prolonged oxycodone in isolated dorsal root ganglia (DRG) neurons and to determine if this tolerance was reversed by either ethanol or a PKC inhibitor. We found that an acute exposure to 3 μM oxycodone reduced neuronal excitability, as measured by increased threshold potentials and reduced action potential amplitude, without eliciting measurable changes in resting membrane potential. Exposure to 10 μM oxycodone for 18-24 hours prevented oxycodone's effect on neuronal excitability, indicative of tolerance development. The development of opioid tolerance was mitigated in DRG neurons from β-arrestin 2 knockout mice. Oxycodone tolerance was reversed in isolated DRG neurons by the acute application of either ethanol (20 mM) or the PKC inhibitor, bisindolylmaleimide XI hydrochloride (Bis XI), when a challenge of 3 µM oxycodone significantly reduced neuronal excitability following prolonged exposure. Through these studies, we concluded that oxycodone acutely reduced neuronal excitability, tolerance developed to this effect, and reversal of that tolerance occurred at the level of a single neuron, suggesting that reversal of oxycodone tolerance by either ethanol or Bis XI involves cellular mechanisms.

Non-Linear Formation of EtG and FAEEs after Controlled Administration of Low to Moderate Doses of Ethanol.

Ethyl glucuronide (EtG) and fatty acid ethyl esters (FAEEs) are non-oxidative metabolites of alcohol that can be detected in conventional and non-conventional biological matrices for longer periods than alcohol. The aim was to describe the time courses of both biomarkers after ingestion of acute low-moderate doses of ethanol. The study design was double-blind, randomized, crossover and controlled with placebo. Participants were distributed in three different cohorts: (a) Cohort-1: two doses of 18 and 30 g of ethanol and placebo were administered to 12 subjects; (b) Cohort-2: two doses of 6 and 12 g of ethanol and placebo were administered to six subjects and (c) Cohort-3: two doses of 24 and 42 g of ethanol and placebo were administered to six subjects. Each participant received two doses of ethanol and placebo. Plasma concentrations (0-6 h) of ethanol and specific FAEEs (palmitic, stearic, linoleic and oleic acid ethyl esters) and urinary concentrations of EtG (0-24 h) were measured. A dose-dependent increase in blood ethanol concentrations was observed. EtG excretion and FAEEs plasmatic concentrations showed a disproportionate increase with the ethanol dose suggesting non-linearity. Area under the curve (AUC0-6h) of ethanol concentrations showed a linear trend with non-oxidative metabolites' concentrations. The formation rate of ethanol non-oxidative biomarkers does not follow a linear trend, explained mainly by a disproportionate increase in AUC0-6h of ethanol concentrations in relation to dose. This observation should be taken into account when interpreting results in biological matrices in clinical and forensic settings. A double-blind, randomized, crossover and controlled study was conducted administering ethanol (6-42 g). Ethyl glucuronide (EtG) excretion and fatty acid ethyl esters (FAEEs) plasmatic concentrations showed a disproportionate increase with the ethanol dose suggesting non-linearity. This observation should be taken into account when interpreting biomarker concentrations in clinical settings.

Conditioned effects of ethanol on the immune system.

Several studies indicate that the immune system can be subjected to classical conditioning. Acute ethanol intoxication significantly modulates several pro-inflammatory cytokines (e.g. interleukins-1 and 6 [IL-1β and IL-6, respectively] and tumor necrosis factor alpha [TNFα])) in several brain areas, including amygdala (AMG), paraventricular nucleus (PVN), and hippocampus (HPC). It is unknown, however, whether cues associated with ethanol can elicit conditioned alterations in cytokine expression. The present study analyzed, in male Sprague-Dawley rats, whether ethanol-induced changes in the central cytokine response may be amenable to conditioning. In Experiments 1 and 2, the rats were given one or two pairings between a distinctive odor (conditional stimulus, CS) and the post-absorptive effects of a high (3.0 or 4.0 g/kg, Experiments 1 and 2, respectively) ethanol dose. Neither of these experiments revealed conditioning of IL-6, IL-1β, or TNFα, as measured via mRNA levels. Yet, re-exposure to the lemon-odor CS in Experiment 1 significantly increased C-Fos levels in the PVN. In Experiment 3, the rats were given four pairings between an odor CS and a moderate ethanol dose (2.0 g/kg), delivered intraperitoneally (i.p.) or intragastrically (i.g.). Re-exposure to the odor CS significantly increased IL-6 levels in HPC and AMG, an effect only evident in paired rats administered ethanol i.p. Overall, this study suggests that ethanol exposure can regulate the levels of IL-6 at HPC and AMG via classical conditioning mechanisms. These ethanol-induced, conditioned alterations in cytokine levels may ultimately affect the intake and motivational effects of ethanol. Impact statement This study examines, across three experiments, whether odor cues associated with ethanol exposure can condition changes in cytokine expression. The analysis of ethanol-induced conditioning of immune responses is a novel niche that can help understand the transition from social drinking to alcohol abuse and dependence. Ethanol-induced conditioning of the immune system could likely exacerbate neuroinflammation and drug-related toxicity, which in turn may facilitate further engagement in ethanol intake. The main new finding of the present study was that, after four pairings of ethanol's unconditioned effects and a distinctive odor, the latter CS increased IL-6 levels in HPC and AMG. This suggests that ethanol's effects upon IL-6 in HPC and AMG may come under conditioned control, particularly after repeated pairings between distinctive odor cues and ethanol's effects. This article advances our knowledge of conditioned increases in cytokine responses, which should help understand the mechanisms underlying alcohol use, abuse, and relapse.

Inhibition of phosphorylated tyrosine hydroxylase attenuates ethanol-induced hyperactivity in adult zebrafish (Danio rerio)

Zebrafish have been successfully employed in the study of the behavioural and biological effects of ethanol. Like in mammals, low to moderate doses of ethanol induce motor hyperactivity in zebrafish, an effect that has been attributed to the activation of the dopaminergic system. Acute ethanol exposure increases dopamine (DA) in the zebrafish brain, and it has been suggested that tyrosine hydroxylase, the rate-limiting enzyme of DA synthesis, may be activated in response to ethanol via phosphorylation. The current study employed tetrahydropapaveroline (THP), a selective inhibitor of phosphorylated tyrosine hydroxylase, for the first time, in zebrafish. We treated zebrafish with a THP dose that did not alter baseline motor responses to examine whether it can attenuate or abolish the effects of acute exposure to alcohol (ethanol) on motor activity, on levels of DA, and on levels of dopamine's metabolite 3,4-dihydroxyphenylacetic acid (DOPAC). We found that 60-minute exposure to 1% alcohol induced motor hyperactivity and an increase in brain DA. Both of these effects were attenuated by pre-treatment with THP. However, no differences in DOPAC levels were found among the treatment groups. These findings suggest that tyrosine hydroxylase is activated via phosphorylation to increase DA synthesis during alcohol exposure in zebrafish, and this partially mediates alcohol's locomotor stimulant effects. Future studies will investigate other potential candidates in the molecular pathway to further decipher the neurobiological mechanism that underlies the stimulatory properties of this popular psychoactive drug.

Adolescent rats are resistant to the development of ethanol-induced chronic tolerance and ethanol-induced conditioned aversion

The analysis of chronic tolerance to ethanol in adult and adolescent rats has yielded mixed results. Tolerance to some effects of ethanol has been reported in adolescents, yet other studies found adults to exhibit greater tolerance than adolescents or comparable expression of the phenomena at both ages. Another unanswered question is how chronic ethanol exposure affects subsequent ethanol-mediated motivational learning at these ages. The present study examined the development of chronic tolerance to ethanol's hypothermic and motor stimulating effects, and subsequent acquisition of ethanol-mediated odor conditioning, in adolescent and adult male Wistar rats given every-other-day intragastric administrations of ethanol. Adolescent and adult rats exhibited lack of tolerance to the hypothermic effects of ethanol during an induction phase; whereas adults, but not adolescents, exhibited a trend towards a reduction in hypothermia at a challenge phase (Experiment 1). Adolescents, unlike adults, exhibited ethanol-induced motor activation after the first ethanol administration. Adults, but not adolescents, exhibited conditioned odor aversion by ethanol. Subsequent experiments conducted only in adolescents (Experiment 2, Experiment 3 and Experiment 4) manipulated the context, length and predictability of ethanol administration. These manipulations did not promote the expression of ethanol-induced tolerance. This study indicated that, when moderate ethanol doses are given every-other day for a relatively short period, adolescents are less likely than adults to develop chronic tolerance to ethanol-induced hypothermia. This resistance to tolerance development could limit long-term maintenance of ethanol intake. Adolescents, however, exhibited greater sensitivity than adults to the acute motor stimulating effects of ethanol and a blunted response to the aversive effects of ethanol. This pattern of response may put adolescents at risk for early initiation of ethanol intake.

Low and moderate prenatal ethanol exposures of mice during gastrulation or neurulation delays neurobehavioral development

Human and animal studies show significant delays in neurobehavioral development in offspring after prolonged prenatal exposure to moderate and high ethanol doses resulting in high blood alcohol concentration (BECs). However, none have investigated the effects of lower ethanol doses given acutely during specific developmental time periods. Here, we sought to create a mouse model for modest and circumscribed human drinking during the 3rd and 4th weeks of pregnancy.We acutely treated mice during embryo gastrulation on gestational day (GD) 7 or neurulation on GD8 with a low or moderate ethanol dose given via gavage that resulted in BECs of 107 and 177mg/dl, respectively. We assessed neonatal physical development (pinnae unfolding, and eye opening); weight gain from postnatal day (PD) 3–65; and neurobehavioral maturation (pivoting, walking, cliff aversion, surface righting, vertical screen grasp, and rope balance) from PD3 to 17. We used a multiple linear regression model to determine the effects of dose, sex, day of treatment and birth in animals dosed during gastrulation or neurulation, relative to their vehicle controls.We found that ethanol exposure during both time points (GD7 and GD8) resulted in some delays of physical development and significant sensorimotor delays of pivoting, walking, and thick rope balance, as well as additional significant delays in cliff aversion and surface righting after GD8 treatment. We also found that treatment with the low ethanol dose more frequently affected neurobehavioral development of the surviving pups than treatment with the moderate ethanol dose, possibly due to a loss of severely affected offspring. Finally, mice born prematurely were delayed in their physical and sensorimotor development.Importantly, we showed that brief exposure to low dose ethanol, if administered during vulnerable periods of neuroanatomical development, results in significant neurobehavioral delays in neonatal mice. We thus expand concerns about alcohol consumption during the 3rd and 4th weeks of human pregnancy to include occasional light to moderate drinking.

Prenatal ethanol exposure alters ethanol-induced Fos immunoreactivity and dopaminergic activity in the mesocorticolimbic pathway of the adolescent brain

Prenatal ethanol exposure (PEE) promotes alcohol intake during adolescence, as shown in clinical and pre-clinical animal models. The mechanisms underlying this effect of prenatal ethanol exposure on postnatal ethanol intake remain, however, mostly unknown. Few studies assessed the effects of moderate doses of prenatal ethanol on spontaneous and ethanol-induced brain activity on adolescence. This study measured, in adolescent (female) Wistar rats prenatally exposed to ethanol (0.0 or 2.0g/kg/day, gestational days 17–20) or non-manipulated (NM group) throughout pregnancy, baseline and ethanol-induced cathecolaminergic activity (i.e., colocalization of c-Fos and tyrosine hydroxylase) in ventral tegmental area (VTA), and baseline and ethanol-induced Fos immunoreactivity (ir) in nucleus accumbens shell and core (AcbSh and AcbC, respectively) and prelimbic (PrL) and infralimbic (IL) prefrontal cortex. The rats were challenged with ethanol (dose: 0.0, 1.25, 2.5 or 3.25g/kg, i.p.) at postnatal day 37. Rats exposed to vehicle prenatally (VE group) exhibited reduced baseline dopaminergic tone in VTA; an effect that was inhibited by prenatal ethanol exposure (PEE group). Dopaminergic activity in VTA after the postnatal ethanol challenge was greater in PEE than in VE or NM animals. Ethanol-induced Fos-ir at AcbSh was found after 1.25g/kg and 2.5g/kg ethanol, in VE and PEE rats, respectively. PEE did not alter ethanol-induced Fos-ir at IL but reduced ethanol-induced Fos-ir at PrL. These results suggest that prenatal ethanol exposure heightens dopaminergic activity in the VTA and alters the response of the mesocorticolimbic pathway to postnatal ethanol exposure. These effects may underlie the enhanced vulnerability to develop alcohol-use disorders of adolescents with a history of in utero ethanol exposure.

Ethanol impairs intestinal barrier function in humans through mitogen activated protein kinase signaling: a combined in vivo and in vitro approach.

BackgroundEthanol-induced gut barrier disruption is associated with several gastrointestinal and liver disorders.AimSince human data on effects of moderate ethanol consumption on intestinal barrier integrity and involved mechanisms are limited, the objectives of this study were to investigate effects of a single moderate ethanol dose on small and large intestinal permeability and to explore the role of mitogen activated protein kinase (MAPK) pathway as a primary signaling mechanism.MethodsIntestinal permeability was assessed in 12 healthy volunteers after intraduodenal administration of either placebo or 20 g ethanol in a randomised cross-over trial. Localization of the tight junction (TJ) and gene expression, phosphorylation of the MAPK isoforms p38, ERK and JNK as indicative of activation were analyzed in duodenal biopsies. The role of MAPK was further examined in vitro using Caco-2 monolayers.ResultsEthanol increased small and large intestinal permeability, paralleled by redistribution of ZO-1 and occludin, down-regulation of ZO-1 and up-regulation of myosin light chain kinase (MLCK) mRNA expression, and increased MAPK isoforms phosphorylation. In Caco-2 monolayers, ethanol increased permeability, induced redistribution of the junctional proteins and F-actin, and MAPK and MLCK activation, as indicated by phosphorylation of MAPK isoforms and myosin light chain (MLC), respectively, which could be reversed by pretreatment with either MAPK inhibitors or the anti-oxidant L-cysteine.ConclusionsAdministration of moderate ethanol dosage can increase both small and colon permeability. Furthermore, the data indicate a pivotal role for MAPK and its crosstalk with MLCK in ethanol-induced intestinal barrier disruption.Trial RegistrationClinicalTrials.gov NCT00928733