Platelet 3H-imipramine binding in euthymic bipolar patients.

Several recent studies have reported decreased maximal binding (beta max) of 3H-imipramine to platelets obtained from depressed patients. 3H-Imipramine binding was measured in 12 medication-free euthymic bipolar patients and 12 normal volunteers to determine whether the decreased beta max persisted in the euthymic state. No differences between these two groups were found in beta max or binding affinity (Kd). This suggests that 3H-imipramine binding to platelets is not a state-independent marker for affective illness.