Lymphocyte beta-adrenoreceptor density in patients with unipolar depression and normal controls

Values of binding maximum (Bmax) and dissociation constant (Kd) of (-)3-[125I]iodocyanopindolol (ICYP) were determined in beta-adrenergic receptors of membranes of peripheral lymphocytes in 32 patients with unipolar depression (DSM-III-R) and 31 normal controls. Results were analyzed by a two-way Analysis of Covariance method. A significant difference was noted for group assignment (patient versus control, p less than 0.05). Mean Bmax (fmol ICYP bound/mg lymphocyte membrane fraction total protein) of patients was 31.9 +/- 3.84 (SE) and controls 46.3 +/- 3.92 (SE). A significant interaction was found between group membership and gender (p less than 0.05). In the female patient group (n = 14), mean Bmax was 30.5 +/- 5.79 (SE); in female controls, mean Bmax was 56.0 +/- 5.15 (SE). Differences between male patients and male controls were not significant. Mean values of Kd (pmol/liter) showed a trend for patient values to be lower than control values [69.0 +/- 13.66 (SE) versus 108.5 +/- 14.42 (SE), respectively]. A significant inverse relationship was noted between lymphocyte beta-receptor Bmax and frequency of panic attacks during the depressive episode in 18 patients (p = 0.05). No relationship was found between values of Kd and frequency of panic attacks in these patients. Thus, preliminary evidence is provided for relationships among altered beta-adrenergic receptor binding, gender, and indices of panic-anxiety in unipolar depressed patients.