Alcoholics with reduced dopamine D2 receptor function possess normal platelet monoamine oxidase activity.

Platelet monoamine oxidase (MAO) activity, proposed to be a marker for central 5-hydroxytryptamine (5-HT) capacity, was investigated in 14 severely alcohol-dependent subjects with reduced dopamine (DA) D2 receptor function, as assessed by the growth hormone responses to apomorphine. Twelve healthy men were used as controls. Platelet MAO activity in the alcohol-dependent subjects was not different from that in controls. The finding from this preliminary study suggests that severely alcohol-dependent subjects with reduced DA D2 receptor function have normal 5-HT capacity.