Local cerebral glucose utilization rates in alcohol-naive high-alcohol-drinking (HAD) and low-alcohol-drinking (LAD) rats

Background: The present study compared baseline local cerebral glucose util ization (LCGU) values within reward-relevant brain regions in alcohol-naive , adult male high-alcohol-drinking (HAD) and low-alcohol-drinking (LAD) rat s from replicate lines I and 2. Methods: 2-[C-14]Deoxglucose ([C-14]2-DG) was injected (125 mu Ci/kg) intra venously during the rats' dark cycle. Timed arterial blood samples were col lected over 45 min and assayed for glucose as well as [C-14]2-DG content. R ats were then decapitated; their brains quickly removed and frozen in isope ntane at -50 degreesC. Coronal sections from each brain were apposed to fil m and exposed for 2 days. Image densities were analyzed using quantitative autoradiography. Results: Data were collected from several key limbic (nucleus accumbens, ve ntral tegmental area, olfactory tubercle, amygdala, hippocampus, ventral pa llidum, and septum), basal ganglia, cortical (medial prefrontal, frontal, p arietal, temporal, occipital, entorhinal, pyriform, and cingulate), and sub cortical (thalamus, habenula, and superior colliculus) structures. Because there were no significant differences between the replicates within each dr inking line, data from the two replicates were combined to determine drinki ng line differences. When both replicate lines were combined, there were tr ends toward higher (approximately 15%) LCGU rates in HAD (n = 15) versus LA D (n = 16)rats within the parietal and occipital cortices, but neither of t hese line differences reached statistical significance (p < 0.01). Conclusions: The findings suggested that, within the HAD and LAD replicate rat lines, the selection for alcohol preference did not lead to differences in functional brain activity, as measured with the 2-DG method.