Decreased gene expression of neuropeptide Y and its receptors in hippocampal regions during ethanol withdrawal in rats

Ethanol withdrawal is associated with neuronal hyperexcitability and increased hippocampal glutamate release. Neuropeptide Y (NPY) appears to play an important role in regulation of hippocampal neuronal excitability by inhibiting glutamate release. Expression of NPY and its receptors Y1, Y2, and Y5 was studied in hippocampal areas of rats during ethanol withdrawal after repeated intragastric ethanol administration for 2 or 4 days using in situ hybridization. Withdrawal was associated with decreased hippocampal expression of NPY and each of its receptors, particularly Y2, after 2 and/or 4 days of ethanol compared to control rats. These data suggest that the hippocampal NPY system is downregulated during ethanol withdrawal and these neuroadaptational changes could play a role in mediating withdrawal hyperexcitability.