Dopamine D-2/D-3-receptor and transporter densities in nucleus accumbens and amygdala of type 1 and 2 alcoholics

Alcohol acts through mechanisms involving the brain neurotransmitter dopami ne (DA) with the nucleus accumbens as the key zone for mediating these effe cts. 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 autora diography of Cloninger type 1 and 2 alcoholics and healthy controls. When c ompared 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 amygd ala, and [I-125]PE21 binding to DA transporters in the nucleus accumbens wa s 39% lower in type 1 alcoholics. These data indicate that dopaminergic fun ctions in these limbic areas may be impaired among type 1 alcoholics, due t o the substantially lower number of receptor sites. Our results suggest tha t such a reduction may result in the chronic overuse of alcohol as an attem pt to stimulate DA function.