A genetic determinant of the striatal dopamine response to alcohol in men.
Level 3 - non-randomized controlled study
Controlled clinical challenge trial stratified by genotype combined with animal experimental models.
PubMed 20479755 · doi:10.1038/mp.2010.56
What was done
Social drinkers were recruited based on their OPRM1 A118G genotype and received alcohol and placebo challenges across separate sessions under pharmacokinetically controlled conditions. Striatal dopamine release was assessed using positron emission tomography (PET) with [11C]-raclopride displacement. To test causality, researchers generated humanized mouse lines carrying either the human 118GG or 118AA sequence variants and measured peak dopamine responses to an alcohol challenge via brain microdialysis.
What was found
In human participants, striatal dopamine response to alcohol was restricted to carriers of the minor 118G allele (no numerical values or effect sizes provided in the abstract). In the animal model, humanized h/mOPRM1-118GG mice exhibited a 4-fold greater peak dopamine response to an alcohol challenge compared to h/mOPRM1-118AA mice.
Why it matters
These findings provide a biological mechanism linking the OPRM1 A118G polymorphism to variations in alcohol-induced dopamine release, helping explain genetic susceptibility to alcohol reward and dependence.
Limits
The abstract does not state the sample size (n), participant demographics, or the exact numerical baseline and response values for the human cohort. The human study focused on men who were social drinkers, limiting generalizability to women or individuals with severe alcohol use disorder. Behavioral reward measures in humans were not reported in the abstract.
Cited by
- supports Individuals carrying a specific variant of the mu-opioid receptor experience a large dopamine increase following alcohol consumption, whereas individuals with the more common variant do not.