to a significantly lesser extent; Martinez et al., 2009). Similar results were obtained with the dopamine releasing agent methylphenidate (Volkow et al., 2007) and amphetamine (Martinez et al., 2005) in alcoholics. Notably, artificially increasing the brain levels of DAD2 receptors, using a replication-deficient adenoviral vector containing the rat cDNA insert for DAD2 into the Nacc, reduces alcohol intake in spontaneously drinking rats, thereby offering the counterproof that a potentiation of DA transmission may have beneficial effects on alcohol-seeking and alcohol-taking, in experimental models (Thanos et al., 2001, 2004). In line with this conclusion, a spontaneous high number of DA D2 receptors has been shown to have a protective role in non-alcoholic members of alcoholic families (Volkow et al., 2006). These findings further support the notion that the number of DA receptors (and consequently DA transmission) inversely correlates with alcohol drinking.
