Cannabinoids and ethanol activate the same reward pathways, and recent advances in the understanding of the neurobiological basis of alcoholism suggest that the CB 1 receptor system may play a key role in the reinforcing effects of ethanol and in modulating ethanol intake. In the present study, male CB 1 receptors knockout mice generated on a CD1 background displayed decreased ethanol-induced conditioned place preference (CPP) compared to wild-type (CB 1 þ / þ ) mice. Ethanol (0.5, 1.0, 1.5, and 2.0 g/kg) induced significant CPP in CB 1 þ / þ mice at all doses tested, whereas it induced significant CPP only at the highest dose of ethanol (2.0 g/kg) in CB 1 À/À mice.However, there was no genotypic difference in cocaine (20 mg/kg)-induced CPP. There was also no genotypic difference, neither in cocaine (10-50 mg/kg) nor in D-amphetamine (1.2-5 mg/kg)-induced locomotor effects. In addition, mutant and wild-type mice did not differ in sensitivity to the anxiolytic effects of ethanol (1.5 g/kg) when tested using the elevated plus maze. Interestingly, this decrease in ethanol efficacy to induce CPP in CB 1 À/À mice was correlated with an increase in D2/D3 receptors, as determined by [ 3 H]raclopride binding, whereas there was no difference in D1-like receptors, as determined by [ 3 H]SCH23390 binding, measured in the striatum from drug-naïve mice. This increase in D2/D3 binding sites observed in CB 1 knockout mice was associated with an altered locomotor response to the D2/D3 agonist quinpirole (low doses 0.02-0.1 mg/kg) but not to an alteration of quinpirole (0.1-1.0 mg/kg)-induced CPP compared to wild-type mice. Altogether, the present results indicate that lifelong deletion of CB 1 receptors reduced ethanol-induced CPP and that these reduced rewarding effects of ethanol are correlated to an overexpression of striatal dopamine D2 receptors.

We identified in the transcriptome analysis of patients with alcoholic hepatitis (AH) osteopontin (OPN) as one of the most up-regulated genes. Here, we used a translational approach to investigate its pathogenic role. OPN hepatic gene expression was quantified in patients with AH and other liver diseases. OPN protein expression and processing were assessed by immmunohistochemistry, Western blotting and ELISA. OPN gene polymorphisms were evaluated in patients with alcoholic liver disease. The role of OPN was evaluated in OPN−/− mice with alcohol-induced liver injury. OPN biological actions were studied in human hepatic stellate cells and in precision-cut liver slices. Hepatic expression and serum levels of OPN were markedly increased in AH compared to normal livers and other types of chronic liver diseases and correlated with short-term survival. Serum levels of OPN also correlated with hepatic expression and disease severity. OPN was mainly expressed in areas with inflammation and fibrosis. Two proteases that process OPN (thrombin and MMP-7) and cleaved-OPN were increased in livers with AH. Patients with AH had a tendency of a lower frequency of the CC genotype of the +1239C SNP of the OPN gene compared to patients with alcohol abuse without liver disease. Importantly, OPN−/− mice were protected against alcohol-induced liver injury and showed decreased expression of inflammatory cytokines. Finally, OPN was induced by LPS and stimulated inflammatory actions in hepatic stellate cells. Conclusion Human and experimental data suggest a role for OPN in the pathogenesis of AH. Further studies should evaluate OPN as a potential therapeutic target.

Acamprosate and naltrexone are effective medications in the treatment of alcoholism. However, effect sizes are modest. Pharmacogenomics may improve patient-treatment-matching and effect sizes. It is hypothesized that naltrexone exerts its effect through genetic characteristics associated with the dopaminergic/opioidergic positive reinforcement system, whereas acamprosate works through the glutamatergic/GABAergic negative reinforcement system. Alcohol-dependent subjects were randomly assigned to either acamprosate or naltrexone. Subjects participated in a cue-exposure experiment at the day before and at the last day of medication. Reductions in cue-induced craving and physiological cue reactivity were measured. Differential effects of naltrexone and acamprosate on these outcomes were tested for different polymorphisms of the opioid, dopamine, glutamate and GABA-receptors. Significant matching effects were found for polymorphisms at the DRD2, GABRA6 and GABRB2 gene. In addition, a trend was found for the OPRM1 polymorphism. This provides evidence for the matching potential of genotypes. It is expected that more effective treatments can be offered when genetic information is used in patient-treatment-matching.

Even though chance finding cannot be ruled out, convergent evidence is given that the DRD1 gene is a susceptibility gene in alcohol dependence, regarding the fact that relying on more homogeneous phenotypes (i.e., more severe patients) and more informative genetic markers (i.e., haplotypes) reinforce the initial association.

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A few clinical studies have shown that dual antidepressants (serotonergic (5-HT) and noradrenergic (NE) transporter inhibitors, SNRIs) may be effective in alcoholism treatment. We studied the effect of the dual antidepressant milnacipran on ethanol operant self-administration in acutely withdrawn ethanol-dependent and in -non-dependent Wistar rats, and used fluoxetine and desipramine to dissect both 5-HT and NE components, respectively, in the effect of milnacipran. Milnacipran was also tested for relapse after protracted abstinence and on ethanol-induced (1.0 g/kg) conditioned place preference in control rats and ethanol-induced locomotor sensitization in DBA/2J female mice. Milnacipran dose dependently (5-40 mg/kg) attenuated the increased ethanol self-administration observed during early withdrawal and was more potent in preventing reinstatement in dependent rats after protracted abstinence as compared with non-dependent rats. Desipramine and fluoxetine (10 mg/kg) blocked ethanol self-administration during early withdrawal, and recovery was delayed in dependent animals, indicating a potent effect. Ethanol self-administration was also reduced 1 day after treatment with desipramine and fluoxetine but not with milnacipran. Finally, milnacipran prevented ethanol-induced place preference in ethanol-naive rats and reduced the magnitude of ethanol-induced sensitization associated with a delayed induction in mice. Desipramine (20 mg/kg) countered sensitization development and reduced its expression at 1 week after treatment; fluoxetine (10 mg/kg) reduced sensitization expression. Thus, 5-HT and NE transmissions during sensitization expression may mediate the effect of milnacipran on sensitization induction. These results support that SNRIs may have a potential use in alcoholism treatment.

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As the contribution of cannabinoid (CB1)