Increased membrane order of erythrocytes in alcoholics as measured by fluorescence polarization: a possible marker for tolerance in alcoholics.

The erythrocyte membranes from 9 healthy non-alcoholic controls and 8 alcoholic patients (fulfilled DSM-III-R criteria for alcohol dependence) were compared for changes in membrane order as measured by fluorescence polarization. The mean amount of change in fluorescence polarization in response to in vitro exposure to ethanol was significantly less in the alcoholics than controls. This increased membrane order of the peripheral blood erythrocytes suggests the presence of pharmacodynamic tolerance to ethanol in the alcoholic patients.