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

Values of binding maximum (B_max) and dissociation constant (K_d) of (-)3-[¹²⁵I]iodocyanopindolol (ICYP) were determined in β-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 < 0.05). Mean B_max (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 < 0.05). In the female patient group (n = 14), mean B_max was 30.5 ± 5.79 (se); in female controls, mean B_max was 56.0 ± 5.15(SE). Differences between male patients and male controls were not significant. Mean values of K_d (pmol/liter) showed a trend for patient values to be lower than control values [69.0 ± 73.66 (se) versus 108.5 ± 14.42 (se), respectively]. A significant inverse relationship was noted between lymphocyte β-receptor B_max and frequency of panic attacks during the depressive episode in 18 patients (p = 0.05). No relationship was found between values of K_d and frequency of panic attacks in these patients. Thus, preliminary evidence is provided for relationships among altered β-adrenergic receptor binding, gender, and indices of panic-anxiety in unipolar depressed patients.