Chronic Alcohol Consumption On The Rat Nucleus Accumbens Spontaneous Electrical Activity And ¦Â-ep Content

Alcohol is the most popular drink and the most widely abused drug. Alcohol dependence induced vast economic, social, family and personal damage. Studying on the neural mechanism of alcohol dependence is very important for the treatment and prevention. The rewarding effect of opiate or alcohol plays the key role in drug dependence. The nucleus accumbens (Nacc) is one of the most important brain regions for rewarding effect. To investigate the neural mechanism of ethanol dependence, the alteration of the EEG and their power spectra in the Nacc of the rats during chronic ethanol exposure and withdrawal were analyzed.Stainless steel recording electrodes were implanted in rats' Nacc in advance. For chronic ethanol treatment studies, the animals received the 6%(V/V) ethanol as their only water intake for 30 days. For withdrawal studies, ethanol was replaced by tap water on the 31th day. The EEG of rat was recorded and analyzed in the different phases of the animals exposure to and withdrawal of ethanol.The EEG of the control rats showed mainly as alpha waves, together with a few decentralized delta and theta waves. The main peaks of the EEG power spectra were in delta and theta frequency range. In the stage of ethanol exposure, the rats exhibited much more act of attack than the control, the alpha waves of EEG decreased, while the delta waves increased. The EEG power spectra analysis showed the delta power increased and the theta power decreased. In the stage of ethanol withdrawal, the rats showed some withdrawal behaviors such as wet dog shakes, sniffing, groomingand tonic-clonic seizures for audiogenic stimulus (lOOdB). Spikes and spike-slow waves were found in the EEG. In power spectra analysis, the delta power decreased while the alpha and the theta power increased, the EEG frequency band moved to the high-frequency rang. These changes were found obviously on the sixth day and disappeared on the 1 Oth day after the ethanol was removed. This study suggests that the spontaneous activity in Nacc neurons of rat could be inhibited by the chronic ethanol exposure. The Nacc neurons of rat could show supersynchronization activity during ethanol withdrawal, and this change is time-dependent. This study also indicates that the spontaneous activity of the Nacc neurons are consistent with the behaviors in the rats chronic exposed to or withdrawn from ethanol.