Platelet monoamine oxidase activity in a nonhuman primate model of type 2 excessive alcohol consumption.

OBJECTIVE

Low platelet monoamine oxidase (MAO) activity is associated with "type 2 alcoholism." MAO activity is also affected by cigarette smoking. Since most alcoholics are smokers, it is difficult to evaluate the possible effect of platelet MAO activity on alcoholism independently of the effects of smoking. The authors investigated the relationship between platelet MAO activity and excessive alcohol consumption in rhesus macaques.

METHOD: Platelet MAO activity and CSF metabolite concentrations were measured. The authors also investigated level of voluntary alcohol intake and social dominance rank.

RESULTS

Subjects with low platelet MAO activity consumed alcohol to excess, had low CSF 5-hydroxyindoleacetic acid concentrations, and were less competent socially.

CONCLUSIONS

These findings show that nonhuman primates that exhibit type 2-like alcohol features display low platelet MAO activity and support the notion that platelet MAO activity is a biologic marker for central serotonergic activity. The results also challenge the hypothesis that low platelet MAO activity in type 2 alcoholism is simply an artifact of smoking.