The Impact of Zonisamide on the Development and Course of Alcohol Dependence in Rabbits. A pharmaco-EEG study

Aims: Zonisamide is a new anti-epileptic drug whose mechanism of action is associated with neurotransmission systems also involved in the pathogenesis of addiction. Recently, the role of memory processes and the hippocampus (Hp) is underlined in dependence. In our previous study, we determined that zonisamide decreases changes in hippocampal bioelectric activity induced by a single dose of ethanol.

Methods: This study uses a pharmaco-EEG method to examine the impact of zonisamide on the development and course of alcohol dependence in rabbits. Quantitative changes in EEG were observed in the midbrain reticular formation, Hp and frontal cortex. Zonisamide was administered p.o. once a day at dose of 30 mg/kg/day during the entire experiment. Solutions with increasing concentrations of ethanol were administered for 6 weeks, followed by a 2-week period of abstinence.

Results: The long-term administration of ethanol caused characteristic changes in rabbit EEG recordings, which were associated with a shift toward lower frequencies resulting in a depressive effect on the bioelectric activity of selected brain structures. Co-administration of zonisamide and ethanol caused a reduction of ethanol-induced alterations. Changes in EEG recordings were different during period of abstinence and were associated with potent shift toward the high frequencies. Zonisamide significantly decreased encephalographic features of neuronal hyperactivity when administered during the abstinence.

Conclusion: Zonisamide decreases ethanol- and abstinence-induced changes in the EEG recordings. These effects may be a significant part of drug's mechanism of action in alcohol addiction therapy.

Short summary: A pharmaco-EEG method was used to determine the influence of a new anti-epileptic drug zonisamide on the development and course of alcohol dependence in rabbits. The drug co-administered with ethanol decreased alcohol-induced changes in selected brain structures. Zonisamide also decreases abstinence-induced changes in the EEG recordings.