• Energy Research

Alcohol dependence (AD) is a chronic and recurrent disease that is a major social and clinical problem. The Food and Drug Administration (FDA) has approved a few drugs for AD treatment like disulfiram, naltrexone and acamprosate. Their efficacy is limited and depends on many additional factors. Also therefore, new methods of therapy are still being sought. Currently, research is focused on a new generation of antiepileptic drugs that could improve the efficiency of AD treatment thanks to their multidirectional mechanism of action associated with neurotransmission systems involved in the pathogenesis of addiction. Topiramate is the most widely studied drug in this area. The results of preclinical studies showed that the drug reduces the intake of ethanol and alleviates symptoms of withdrawal syndrome in animals. The results of clinical observations in patients with AD confirmed the efficacy of topiramate in reducing alcohol consumption and number of heavy drinking days and prolonging the abstinence period. In comparative studies with naltrexone, topiramate to a greater extent reduced craving. Despite these promising results, there is still a need for further research on the influence of the drug on the development and course of alcohol dependence.

Topiramate causes the inhibition of alcohol consumption in addicts but the mechanism of this action has not been fully understood yet. Nowadays, it seems that memory may have a role in the development of dependence. In this study, the impact of topiramate and ethanol on the bioelectric activity of the brain in rabbits and on spatial memory in rats was evaluated.The aim of the study was to assess the effect of co-administration of topiramate and ethanol on bioelectric activity of the rabbits' brain and on spatial memory in rats. Topiramate decreased ethanol-induced changes in all studied brain structures and improved memory and learning processes.A pharmaco-electroencephalography study was used to examine the effect of topiramate (25 mg/kg/day) co-administered for 6 weeks with ethanol on the bioelectric activity of the rabbits' brain. The influence of the drug was also assessed in first and second weeks of the abstinence period. Spatial memory was evaluated in rats using Morris water maze task. Topiramate (60 mg/kg/day) was administered with the ethanol for 3 weeks and for 2 weeks in the abstinence.After 6 weeks of topiramate and ethanol administration, the drug decreased ethanol-induced changes in the midbrain reticular formation, hippocampus and frontal cortex. In the abstinence, the drug also inhibited the features of neuronal hyperactivity, especially in the hippocampus. Moreover, topiramate co-administered with ethanol for 3 weeks decreased ethanol-induced memory disturbance in rats. This beneficial effect was also observed in the second week of abstinence.These findings reveal that 'antialcoholic' activity of topiramate may be associated with its advantageous effect on memory and learning processes.

Oxcarbazepine is a representative molecule for a new class of anticonvulsant drugs that can treat alcohol dependence in addition to other disorders. Interestingly, the central mechanism of action in oxcarbazepine is very similar to ethanol, suggesting that these two agents may interact and cause enhanced effects in the central nervous system. In this study, we used a pharmaco-EEG method to examine the influence of oxcarbazepine on the effect of ethanol on the EEG of rabbits (midbrain reticular formation, hippocampus, frontal cortex). Oxcarbazepine was administered po as a single dose (20 mg/kg or 80 mg/kg) or repeatedly at a dose of 40 mg/kg/day for 14 days. Ethanol was injected iv at a dose of 0.8 g/kg 60 min after the administration of oxcarbazepine. Ethanol caused an increase in the low frequencies (0.5-4 Hz) in the recordings, and it caused a marked decrease in higher frequencies (13-30 Hz and 30-45 Hz). Oxcarbazepine altered the EEG pattern in rabbits; this interaction was dependent on the dose of the drug and whether it was administered as a single dose or as multiple doses. Oxcarbazepine administered at a lower dose had a synergistic effect with ethanol in the frontal cortex and midbrain reticular formation, and a similar effect was observed in the hippocampus at a higher dose. Changes in EEG recordings after the administration of oxcarbazepine alone were more pronounced after multiple administrations. The drug decreased the sensitivity of the hippocampus to ethanol, an observation that may be important for the treatment of alcohol addiction.

Recent research suggests a potential role for a new generation of anticonvulsant drugs, including zonisamide, in the treatment of alcohol dependence. Some elements of the central mechanism of action that zonisamide has in common with ethanol, give rise to the question of whether there is an interaction between these two agents and whether there is any risk associated with the enhanced depressive effect of these agents on the central nervous system.This study uses a pharmaco-EEG method to examine the interaction of ethanol with zonisamide. The influence of zonisamide on the effect of ethanol on EEG of rabbits (midbrain reticular formation, hippocampus, frontal cortex) was determined. Zonisamide was administered p.o. as a single dose (20 or 60 mg/kg) or repeatedly at a dose of 30 mg/kg/day for 14 days. Ethanol was injected i.v. at a dose of 0.8 g/kg 180 min after the administration of zonisamide.Ethanol caused an increase in the low frequencies (0.5-4 Hz) in the recording, as well as a marked decrease in the higher frequencies (13-30 and 30-45 Hz). Changes in the EEG recordings after zonisamide alone were more significant compared with these after repeated doses. In the hippocampus after single dose of drug the proportion of the low frequency (0.5-4 Hz) increased, whereas the proportion of high frequencies decreased. Combined administration of ethanol and zonisamide (60 mg/kg) resulted in a markedly synergistic effect in the examined structures. A beneficial effect of repeatedly administered zonisamide on ethanol-induced EEG changes was observed, especially in the hippocampus.Zonisamide in repeated doses decreases the sensitivity of the hippocampus to ethanol, an observation that may be important in the treatment of alcohol addiction.

The influence of nifedipine, verapamil, and cinnarizine on the effect of ethanol on EEG of rabbits (frontal cortex, hippocampus, MRF) was tested. Nifedipine (1.75 mg/kg, IP) and cinnarizine (7.5 mg/kg, IP) were given 30 min before ethanol administration. Verapamil (0.2 mg/kg, IV) was given 15 min before ethanol injection in a dose of 0.8 g/kg IV. Ethanol caused the increase of the frequencies 0.5-4 cps in the recording, as well as a marked decrease of the fastest frequencies. Verapamil prevented ethanol's effect on EEG recording. Cinnarizine antagonized this action to a smaller extent and the influence of nifedipine is transitory and less pronounced.

In this study we have decided to examine acute interaction of ethanol with some drugs that belong to selective serotonin inhibitor (SSRI) group. Therefore, the influence of sertraline, fluoxetine and citalopram on the effect of ethanol on EEG of rabbits (frontal cortex, hippocampus, MRF) was tested. Sertraline (10mg/kg i.p.), fluoxetine (10mg/kg i.p.) and citalopram (5mg/kg i.p.) were given 30min before ethanol injection in a dose 0.8g/kg i.v. Ethanol caused the increase of the slow frequencies (0.5-4cps) in the recording, as well as a marked decrease of the fastest frequencies (13-30 and 30-45cps). Sertraline, fluoxetine and citalopram (given before ethanol) prevented the increase in the slow frequencies (0.5-4cps) in the recordings from the frontal cortex and hippocampus, which indicates on antagonism inhibitory action of ethanol. These drugs administered together with ethanol may increase its influence on fast frequencies. This effect depends on brain structure and drug.

Retigabine is a new antiepileptic drug with multiple mechanisms of action. It may well interact with ethanol, as both have an influence on GABA-ergic and glutamate neurotransmission.To assess the effect of retigabine, administered as single or repeated doses, on ethanol-induced changes in the bioelectric activity of selected brain structures in rabbits.30 rabbits were used to assess the effect of retigabine on ethanol-induced changes in EEGs using the pharmaco-EEG method. Retigabine was administered p.o. as a single dose (5 mg/kg or 10 mg/kg) or repeatedly at a dose of 5 mg/kg/day for 14 days. Ethanol was injected i.v. at a dose of 0.8 g/kg 60 min after the administration of retigabine.Retigabine, administered as a single high or low dose, increased the depressive effect of an acute dose of ethanol on the bioelectric activity of the frontal cortex in rabbits. These changes were also visible in the recordings from the hippocampus and midbrain reticular formation after administration of a high dose of the drug. Retigabine administered in repeated doses decreased ethanol-induced changes in the rabbit EEG recordings from the hippocampus.Retigabine in multiple doses decreases the sensitivity of the hippocampus to an acute dose of ethanol in rabbits. Given the role of hippocampal-related memory processes to addiction, retigabine may have therapeutic potential.

The interaction of mianserin with ethanol in central nervous system (CNS) was investigated. Mianserin was administered at a single dose of 5 or 20 mgkg(-1) i.p. or as daily injections in a dose of 2.5 mgkg(-1) given for 14 days. The influence of mianserin on acute ethanol toxicity (LD(50)), on ED(50) of ethanol in rota-rod test, on the duration of ethanol sleeping time as well as on spontaneous locomotor activity and ethanol-induced hypothermia was investigated. Moreover, the influence of mianserin administered in a dose of 10 mgkg(-1) i.p. on post-ethanol changes in the bioelectric brain activity (EEG) recordings in rabbits was also investigated. The electrodes were implanted into midbrain reticular formation (MRF), dorsal hippocampus (Hp) and frontal cortex (C). Mianserin administered as a single dose of 5 mgkg(-1) was found to decrease LD(50) of ethanol and its ED(50) in rota-rod test. Mianserin administered as a single dose of 5 or 20 mgkg(-1) prolongs ethanol sleeping time in mice but given daily for 14 days has no influence on this time. Mianserin-induced hypothermia was observed after administration of single dose as well as increase of ethanol-induced hypothermia after administration of higher dose (20 mgkg(-1)). Mianserin administered daily for 14 days had no influence on post-ethanol changes in body temperature. Single dose of mianserin 20 mgkg(-1) decreases locomotor activity in mice while repeated administration has no influence on locomotor activity. In contrast, both single dose and repeated administration of mianserin prevents increased locomotor activity of animals observed after ethanol (2.5 mgkg(-1)). Mianserin administered to rabbits (10 mgkg(-1)) induces increase of share of low frequency 0.5-4 cps and decrease of share of frequencies 4-7 and 7-10 cps in EEG recordings from MRF and Hp. The recordings from frontal cortex show increase of share of frequencies 10-13 cps. Ethanol increases the share of low frequencies in EEG recordings and decreases the share of fast frequencies. Mianserin increases its influence on fast frequencies.