The binge drinking animals also had decreased expression of genes involved in myelin formation, which has been noted in other tissues (Lewohl et al., 2000, Mayfield et al., 2002, McClintick et al., 2013, Sokolov et al., 2003, and in pre-clinical models of adolescent binge drinking (Vargas et al., 2014). Decreased myelination and poorer myelin integrity have also been found in adolescents with extensive alcohol use (Jacobus and Tapert, 2013). Decreased myelination during adolescent development could have a major impact on brain function. It is unknown whether decreased cholesterol production is the cause of decreased myelination in the brains of alcoholics but Hmgcs1 and Hmgcr in the biosynthetic pathway also had decreased expression in the hippocampus of alcoholics, who also had decreased expression of myelin forming genes (McClintick et al., 2013). Expression of both myelin-related genes and Hmgcr is decreased in post-mortem studies of frontal and motor cortex and temporal cortex (Mayfield et al., 2002; Sokolov, et al., 2003). Hmgcr, Hmgcs1, Dhcr7 and Sqle all had decreased expression in the VTA of binge drinking adult female P rats (McBride et al., 2013a).
