Evaluation of Ethanol Administration in Swiss Mice After Chronic Antianxiety Treatment

Alcohol use disorder (AUD) is frequently associated with anxiety disorders, and the interaction between anxiolytic medications and ethanol consumption remains poorly understood. Clonazepam, a benzodiazepine that enhances γ-aminobutyric acid (GABA)-mediated neurotransmission, shares several neuropharmacological mechanisms with ethanol and may influence alcohol-seeking behavior. The present study investigated the effects of chronic clonazepam treatment on ethanol self-administration, ethanol intake, and anxiety-like behavior in Swiss albino mice. Male Swiss mice were trained to self-administer a 10% (w/v) ethanol solution using an operant conditioning paradigm. Following the establishment of stable baseline ethanol consumption, animals received clonazepam (0.5 mg/kg, i.p.) or vehicle according to the experimental protocol. Ethanol rewards, ethanol intake, water consumption, and total fluid intake were monitored throughout the study. Anxiety-like behavior was assessed using the Elevated Plus Maze (EPM), while locomotor activity was evaluated using an actophotometer. Blood ethanol concentrations were measured to validate ethanol self-administration behavior. Chronic clonazepam treatment significantly altered ethanol consumption patterns. Acute clonazepam exposure initially reduced ethanol self-administration and intake; however, prolonged treatment produced a significant increase in ethanol rewards, ethanol intake, and ethanol preference compared with baseline and vehicle-treated controls (p < 0.05). A significant positive correlation was observed between ethanol rewards and blood ethanol concentrations (p < 0.0001). In the EPM, clonazepam-treated mice spent significantly more time in the open arms and less time in the closed arms, indicating marked anxiolytic-like activity. No significant changes in locomotor activity were observed. These findings demonstrate that chronic clonazepam treatment exerts a biphasic effect on ethanol consumption while maintaining anxiolytic efficacy. Long-term benzodiazepine exposure may enhance alcohol-directed behaviors, highlighting potential implications for the management of anxiety disorders coexisting with alcohol use disorder.