A recent report combined a placebo-controlled intravenous alcohol administration with positron emission tomography methodology to examine the striatal DA response to alcohol in social-drinking male Asp40 carriers and Asn40 homozygotes (Ramchandani et al., 2011). Using 11C-raclopride, this study showed that Asp40 carriers displayed a more potent striatal DA response to alcohol as compared to individuals who were homozygous for the Asn40 allele. In conjunction, the 2 neuroimaging studies described above have supported the biological plausibility of this polymorphism as a determinant of alcohol-induced reward, both in terms of hemodynamic response (Filbey et al., 2008b) and DA release in the striatum following alcohol exposure. A functional neuroimaging study of social pain has implicated the Asp40 allele with greater neural response to a social rejection task, as well as with greater dispositional levels of social rejection sensitivity (Way et al., 2009). Together, these studies have begun to elucidate the neural bases of differential response to alcohol conferred by this polymorphism and have suggested that these mechanisms may not be alcohol-specific and instead may apply to a host of psychological domains.
