Dopamine D2 receptors and transporters in type 1 and 2 alcoholics measured with human whole hemisphere autoradiography.
Level 4 - case-series / case-control
Human postmortem case-control comparative study
PubMed 14505335 · doi:10.1002/hbm.10129
What was done
Human postmortem whole hemispheric autoradiography using [125I]epidepride was performed to measure striatal dopamine D2 receptor densities in Cloninger type 1 alcoholics, Cloninger type 2 alcoholics, and non-alcoholic controls. The investigators also evaluated correlations between dopamine transporter (DAT) and D2 receptor binding site densities, as well as correlations in [125I]epidepride binding between dorsal striatal regions (caudate, putamen, globus pallidus) and the nucleus accumbens.
What was found
Type 1 alcoholics showed 21.4% to 32.6% lower dopamine D2 receptor density across all dorsal striatal structures (caudate, putamen, globus pallidus) compared with controls. Type 2 alcoholics exhibited 19.6% to 21.4% lower binding in dorsal striatal structures, except in the medial globus pallidus where binding did not differ significantly from controls. A significant positive correlation between D2 receptor and DAT density was found exclusively in the putamen of type 1 alcoholics. Furthermore, [125I]epidepride binding showed significant positive correlations between the nucleus accumbens and all dorsal striatal areas in type 1 alcoholics (absent in controls), whereas type 2 alcoholics showed weaker correlations and no correlation between the nucleus accumbens and globus pallidus.
Why it matters
This study provides postmortem evidence that Cloninger type 1 and type 2 alcoholics display distinct neurochemical alterations in striatal dopamine D2 receptor binding and regional connectivity, supporting biological heterogeneity between alcoholism subtypes.
Limits
The abstract does not state the sample size (n) for any group. As a postmortem observational study, it cannot determine whether altered dopamine receptor density is a pre-existing vulnerability trait or a consequence of chronic alcohol neurotoxicity. Key confounders such as postmortem interval, cause of death, toxicological history, and comorbid substance use are not reported in the abstract.
Cited by
- supports People with alcohol use disorder have lower dopamine receptor density and lower dopamine transporter density compared to people without alcohol use disorder.