Up-regulation of cortical AMPA receptor binding in the fawn-hooded rat following ethanol withdrawal.

The present study has employed quantitative receptor autoradiography to compare the binding of (S)-[3H]5-fluorowillardiine to (S)-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) receptors in the brains of alcohol-preferring Fawn-Hooded (FH) rats, alcohol non-preferring Wistar-Kyoto (WKY) rats, and FH rats following a 28-day period of 5% ethanol consumption with or without ethanol withdrawal. Significantly higher binding of [3H]5-fluorowillardiine was found in the cingulate cortex (+12%) and claustrum (+13%) in alcohol naïve FH rats compared to WKY rats. Chronic ethanol consumption decreased binding of (S)-[3H]5-fluorowillardiine in four cortical regions (frontal, parietal, occipital and temporal cortex), hippocampus and septohippocampal nucleus. In contrast, ethanol withdrawal induced a significant "rebound" increase in binding by +22% in frontal and parietal cortex, by +17% in cingulate cortex and +13% in claustrum, and by +14% in the septohippocampal nucleus compared to chronic ethanol-exposed FH rats. The findings suggest that AMPA receptors in frontal cortical regions are sensitive to ethanol and therefore may be implicated in the predisposition of alcohol preference in FH rats.