Mice were given either water or ethanol (5g/kg, i
Mice were given either water or ethanol (5g/kg, i.g.) in an intermittent fashion (2 days on 2 days off) during adolescence (P2837). not impact adult Barnes Maze learning. However, AIE did cause reversal learning deficits in adults. AIE also caused structural changes in the adult brain. AIE was associated with adulthood volume enlargements in specific brain regions without changes in total brain volume. Enlarged regions included the orbitofrontal cortex (OFC, 4%), cerebellum (4.5%), thalamus (2%), internal capsule (10%) and genu of the corpus callosum (7%). The enlarged OFC volume in adults after AIE is usually consistent with previous imaging studies in human adolescents. AIE treatment was associated with significant increases in the expression of several extracellular matrix (ECM) proteins in the adult OFC including WFA (55%), Brevican (32%), Neurocan (105%), Tenacin-C (25%), and HABP (5%). These findings are consistent with AIE causing persistent changes in brain structure that could contribute to a lack of behavioral flexibility. Keywords:underage drinking, MRI, extracellular matrix, alcohol, neurocan, behavioral flexibility == 1.1 Introduction == Adolescent human drinkers SB939 ( Pracinostat ) participate in heavy and binge drinking (>5 drinks/episode) at substantially higher rates than adults (Ehlers et al., 2011;Lucantonio et al., 2012;SAMSA, 2007), with the rate of binge-drinking peaking during adolescence (Ehlers et al., 2011). Alcohol consumption during adolescence is usually highly prevalent as 8% of 8thgrade, 16% of 10th grade, and 25% of 12thgrade adolescent individuals reported heavy episodic drinking (i.e., <5 consecutive alcohol drinks per episode) over the past 2 weeks (Johnston et al., 2009). This heavy drinking pattern persists into college as 44% of students report binge drinking every 2 weeks with 19% reporting more than 3 binge drinking episodes per week (O'Malley et al., 1998;Wechsler et al., 1995). Early onset of alcohol use (<13 years of age) is associated with increased drinking frequency and physical violence (Gruber et al., 1996). Further, large population studies find that across the teenage years the earlier the age of drinking onset the greater the risk of lifetime alcohol use disorder (Zhu et al., 2010) and lifetime alcohol related violence and injuries (Hingson and Winter, 2003;White et al., 2011). Adolescents with alcohol use disorders have deficits in executive functioning (Brown et al., 2000;Hanson et al., 2011;Tapert and Brown, 2000) consistent with frontal cortical dysfunction. Although studies have found that heavy drinking among adolescent males increases impulsivity the following year in those individuals predisposed to adolescent-typical impulsivity (White et al., 2011), human studies are all confounded by the difficulty in distinguishing a pre-existing condition that leads to alcohol abuse from an alcohol induced dysfunction that alters the individual beyond the period of intoxication. Adolescence is usually a developmental period associated with maturation of cognitive ability, personality and frontal cortical executive functions (Crews et al., 2007;Gong et al., 2012;Spear, 2000). The frontal cortex continues to develop throughout adolescence and is uniquely sensitive to ethanol neurotoxicity (Crews et al., 2000). Adolescent rat ethanol treatment results in greater frontal cortical damage than adults as well as other alterations in adult brain neurotransmission (Basak and Bandyopadhyay, 2013;Coleman et al., 2011;Sharma and Bhatia, 2004;Torchilin, 2001), electrophysiological activity and sleep wave patterns (Escobar-Chavez et al., 2006), reduced forebrain cholinergic-choline acetyltransferase + neurons (Coleman et al., NOX1 2011;Ehlers et al., 2011) and reduced hippocampal neurogenesis (Ehlers et al., 2011). Further, adolescent rat ethanol treatment increases alcohol intake (Fabio et al., 2013;Pascual et al., 2007) and risk-taking preference (Qin et al., 2013), as well as impairing conditioned discrimination, object recognition (Pascual et al., 2007), and reversal learning (Coleman et al., 2011). These studies support the hypothesis that adolescent binge-drinking impacts the brain and behavior in SB939 ( Pracinostat ) a manner that persists into adulthood. Human adolescents drink mostly in a unique binge drinking on-off-on intermittent temporal SB939 ( Pracinostat ) pattern, drinking at the SB939 ( Pracinostat ) end of the week and on weekends and abstaining during the first 34 days of the week (Zou and Crews, 2012). Daily.