Up-regulation of cortical AMPA receptor binding in the Fawn-Hooded rat following ethanol withdrawal

The present study has employed quantitative receptor autoradiography to com pare the binding of (S)-[H-3]5-fluorowillardiine to (S)-alpha-amino-3-hydro xy-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 wit h or without ethanol withdrawal. Significantly higher binding of [H-3]5-flu orowillardiine was found in the cingulate cortex (+12%) and claustrum (+13% ) in alcohol naive FH rats compared to WKY rats. Chronic ethanol consumptio n decreased binding of (S)-[H-3]5-fluorowillardiine in four cortical region s (frontal, parietal, occipital and temporal cortex), hippocampus and septo hippocampal nucleus. In contrast, ethanol withdrawal induced a significant "rebound" increase in binding by +22% in frontal and parietal cortex, by +1 7% in cingulate cortex and +13% in claustrum, and by +14% in the septohippo campal nucleus compared to chronic ethanol-exposed FH rats. The findings su ggest that AMPA receptors in frontal cortical regions are sensitive to etha nol and therefore may be implicated in the predisposition of alcohol prefer ence in FH rats. (C) 1999 Elsevier Science B.V. All rights reserved.