Effects of ethanol drinking on central nervous system functional activity of alcohol-preferring rats

The [14C]-2-deoxyglucose (2-DG) technique was used to assess the rates of local cerebral glucose utilization (LCGU) in key limbic, cerebral cortical, hippocampal, basal ganglionic, and subcortical regions of alcohol-preferring (P) rats following chronic 24-h free-choice ethanol drinking. Adult male P rats were submitted to (1) 8 continuous weeks of two-bottle access to 15% ethanol and water (E-C group); (2) 8 weeks of identical two-bottle access followed by 2 weeks of ethanol deprivation (E-D group); (3) cycles of 2 weeks of two-bottle ethanol access and 2 weeks of deprivation, repeated for four cycles (E-RD group); or (4) water only treatment [ethanol-naive group (E-N group)]. A single pulse of [14C]-2-DG (125 μCi/kg) was administered via a venous catheter, and timed arterial blood samples were collected over 45 min and later assayed for plasma glucose and [14C]-2-DG concentrations. Quantitative autoradiography was used to determine [14C] densities, and LCGU values were calculated. With the exception of a few small differences in the hippocampus, no significant differences were found in any of the central nervous system (CNS) regions examined among the four experimental groups of P rats. Animals in the E-D group had lower LCGU rates in the anterior hippocampal CA1 subregion than animals in the E-N, E-C, and E-RD groups. In the anterior hippocampal CA3 subregion and the anterior hippocampal dentate gyrus, the E-D group had significantly lower LCGU rates than the E-RD group. Overall, the results of this study indicate that 24-h ethanol-drinking experience has little effect on CNS functional neuronal activity in P rats.