Dopamine D2/D3-receptor and transporter densities in nucleus accumbens and amygdala of type 1 and 2 alcoholics

Alcohol acts through mechanisms involving the brain neurotransmitter dopamine (DA) with the nucleus accumbens as the key zone for mediating these effects. We evaluated the densities of DA D-2/D-3 receptors and transporters in the nucleus accumbens and amygdala of post-mortem human brains by using [I-125]epidepride and [I-125]PE21 as radioligands in whole hemispheric autoradiography of Cloninger type 1 and 2 alcoholics and healthy controls. When compared with controls, the mean binding of [I-125]epidepride to DA D-2/D-3 receptors was 20% lower in the nucleus accumbens and 41% lower in the amygdala, and [I-125]PE21 binding to DA transporters in the nucleus accumbens was 39% lower in type 1 alcoholics. These data indicate that dopaminergic functions in these limbic areas may be impaired among type 1 alcoholics, due to the substantially lower number of receptor sites. Our results suggest that such a reduction may result in the chronic overuse of alcohol as an attempt to stimulate DA function.