ABSTRACT
Over half a century of dedicated and rigorous scientišc research on the mesolimbic system provided insight into the addictive brain and neurogenetic mechanisms involved in man’s quest for happiness. In brief, the site of the brain where one experiences feelings of well-being is the mesolimbic system. This part of the brain has been termed the reward center. Chemical messages, including serotonin, enkephalins, γ-aminobutyric acid (GABA), and dopamine (DA), work in concert to provide a net release of DA at the nucleus accumbens (NAc), a region in the mesolimbic system. It is well known that genes control the synthesis, vesicular storage, metabolism (Baker et al., 1994), receptor formation, and neurotransmitter catabolism (Hodge et al., 1996; Hodge and Cox, 1998). The polymorphic versions of these genes have certain variations that could lead to an impairment of the neurochemical events involved in the neuronal release of DA. The cascade of these neuronal events has been termed brain reward cascade (Blum et al., 1990) (Figure 26.1).
