Platelet monoamine oxidase-B activity in alcoholics with lowered dopamine D2 receptor activity.

This letter is a report on a comparison between two methods of assessment of dopamine function in a group of abstinent alcoholics, one a neuroendocrine challenge test using a dopaminergic probe, and the other a measurement of platelet monoamine oxidase (MAO) enzyme activity. This enzyme is on the dopamine degradation pathway and has been reported as having diminished activity in alcoholics (Pandey et al, 1988; Faraj et al, 1994). Balldin et al. (1994) reported in this journal evidence that a group of alcoholics with a reduced dopamine D2 receptor function, as explored using a neuroendocrine challenge, relative to healthy controls, possessed normal platelet monoamine oxidase activity. These authors, however, failed to compare the level of platelet MAO activity between alcoholics with and without reduced dopamine function.