Adolescent and adult animals used for determination of ethanol concentrations were naive to any experimental manipulation until being food and fluid deprived for 120 min prior to injection of 0.5 or 2.0 g/kg ethanol, on P32 or P70, respectively. Animals were individually placed in pine-shaving lined containers, with brain and blood ethanol samples taken at 7.5 or 32.5 min after ethanol administration. Trunk blood (2 μl samples) was obtained through decapitation, employing a heparinized capillary tube, and centrifuged at high speed (15 min / 3000 rpm; Micro-Haematocrit Centrifuge, Hawksley & Sons LTD, Sussex, England). Blood samples were processed by means of an AM1 Alcohol Analyzer (Analox Instruments, Lunenburg, MA). The apparatus estimates BELs by oxidating ethanol to acetaldehyde in the presence of ethanol oxidase. This process is oxygen-dependent and the quantity of O2 is proportional to ethanol concentration. Whole brains were collected, maintained in a -80° C freezer and later sonicated in a water solution as previously described by Silveri & Spear (2000). These samples were analyzed for ethanol content by means of a head-space gas-chromatograph method (Hewlett Packard 5890
