Ethanol changes the electroencephalographic correlation of the ventral tegmental area and nucleus accumbens, components of the mesoaccumbens system in rats

Alcohol consumption produces various behavioral effects and its administration is associated with increases of dopamine (DA) levels in the nucleus accumbens (Acc). However, it is not yet clear if these behavioral and neurochemical effects are associated with a different functionality of the Acc and ventral tegmental area (VTA), the neural structures that constitute the dopaminergic mesoaccumbens system. The present study was designed to analyze whether the electroencephalographic (EEG) correlation between the Acc and VTA shows characteristic changes after the forced administration of ethanol in male rats. Simultaneous EEG recordings were obtained from the left and right Acc and VTA in adult male rats during a 40 min period immediately after an i.p. injection of ethanol (15% v/v in a dose of 0.75 g/kg). During the 40 min period after i.p. ethanol administration, an increase of the fast frequencies (13-21 Hz) was observed in Acc and VTA. The interaccumbens correlation showed a significant decrease in the theta frequencies (4-7 and 8-12 Hz bands), whereas the intrahemispheric r in both hemispheres showed a clear increase in the fast frequencies. The possible participation of the mesoaccumbens system in the arousal state and in the motivo-emotional aspects of ethanol is suggested.