Time dependent alterations on tyrosine hydroxylase, opioid and cannabinoid CB1 receptor gene expressions after acute ethanol administration in the rat brain.

The aim of this study was to examine the differential regulation after acute ethanol administration on tyrosine hydroxylase, proenkephalin and cannabinoid CB(1) receptor gene expressions in selected areas of the rat brain. Rats received an intragastric administration of 3 g/kg ethanol and were killed by decapitation at 1, 2, 4, 8 and 24 h. The results showed an activation of tyrosine hydroxylase gene expression in the ventral tegmental area and the substantia nigra, increased proenkephalin gene expression in the caudate-putamen, nucleus accumbens core and shell, central and medial amygdala, ventromedial hypothalamic nucleus and the paraventricular hypothalamic nucleus. In contrast, a significant decrease in the cannabinoid CB1 receptor gene expression was found in caudate-putamen, central amygdala and ventromedial hypothalamic nucleus. In conclusion, the results suggest that an acute dose of ethanol induces neuroplastic alterations in proenkephalin, tyrosine hydroxylase and cannabinoid CB1 receptor gene expressions that may contribute to trigger the rewarding effects of ethanol consumption.