α6GABAAR POSITIVE ALLOSTERIC MODULATOR AS A NOVEL THERAPY FOR ALCOHOL WITHDRAWAL SYNDROME

Abstract Background Alcohol use disorder (AUD) is a disease manifested by compulsive use of alcohol, the inability to control intake, and characterized by repeated cycles of intoxication, withdrawal, craving, and relapse. Alcohol withdrawal syndrome (AWS), like anxiety, tremor, and hyperthermia, is the leading cause of the high relapse rate in heavy drinkers. Alcohol can facilitate GABA action and down-regulate GABA receptors after long-term use. Aims & Objectives Clinically AWS is usually treated with GABAAR positive allosteric modulators (PAMs), like benzodiazepines and barbiturates. However, the combination of benzodiazepines and alcohol is hazardous, leading to life-threatening consequences. Therefore, developing a safer and more efficient therapy is crucial for treating AWS/AUD, mainly focusing on the GABAergic system. Method Here, we employed an AUD animal model well-established previously by giving rats intermittent (every other day) access to ethanol (20%) in a 2-bottle choice (IA2BC) procedure (Fig. 1A). After the eight-week IA2BC test, we performed different behavioral tests to evaluate the AWS in our animal model. The light-dark box, open field test, and marble-burying test were used to assess anxiety-related behaviors in rats. Our international collaborating team identified a series of pyrazoloquinolinones (PQs) as the first α6GABAAR-selective PAMs. Hence, we evaluated whether these PQs could be used as a potential novel therapy for treating AWS/AUD. Statistical significance was determined using a two-way ANOVA followed by a Bonferroni post hoc test on raw data. Results The rats exposing to alcohol under the IA2BC procedure for eight weeks gradually increased the intake of alcohol, but not water, with a significant ethanol preference from four weeks (Fig. 1B). In these alcohol- dependent rats after 7 days’ abstinence, we observed significant anxiety-like behaviors in the marble- burying (Fig. 1C) and light-dark box (Fig. 1D). In the open field test (Fig. 1E), the alcohol-dependent rats showed less exploration and hypo-locomotion after alcohol withdrawal. We speculate that the decreased locomotion activity is probably related to depression or stress. In contrast, DK-I-56-1 (one of PQs) significantly alleviated the anxiety-related behaviors in both marble-burying and light/dark box tests (Fig. 1C-D), especially on the first withdrawal day. Discussion & Conclusion Our preliminary results showed that DK-I-56-1 could significantly improve AWS. Since the AWS period brings great discomfort and intense cravings to the patient, the patient turned to use alcohol, presumably for symptom relief. Hence, we believe α6GABAARs may be a therapeutic target of AUD/AWS.