Korean Journal of Biological Psychiatry

This study was designed to examine the basal cyclic AMP levels and the 10^-5mol/L isoproterenol-stimulated cyclic AMP levels of lymphocytes, by which B-adrenoceptor function was shown, between 10 normal controls and 17 drug free patients(8 major depressive patients and 9 dysthymic patients), who were diagnosed by DSM-III-R. The severity of depression was assessed by Hamilton Rating Scale for Depression(HDRS). Cyclic AMP levels were measured by radioimmunoassay(double antibody). The results were as follows ; 1) HDRS score was significantly higher in major depressive patients(41.8±4.6) than in dysthymic patients(24.0±4.2)(p<0.05). 2) There was no significant difference in basal cyclic AMP levels among normal controls(3.9±1.7 pmol/10⁶cells/10min), major depressive patients(2.1±0.5 pmol/10⁶cells/10min), and dysthymic patients(3.9±1.8 pmol/10⁶cells/10min). 3) There was significant difference in net cyclic AMP levels(10^-5mol/L isoproterenol-stimulated cyclic AMP levels minus basal cyclic AMP levels) among normal controls(16.5±6.0 pmol/10⁶cells/10min), major depressive patients(3.0±1.4 pmol/10⁶cells/10min), dysthymic patients(10.9±4.4 pmol/10⁶cells/10min)(p<0.05). 4) The net cyclic AMP levels were significantly correlated with HDRS scores in major depressive patients(y=-0.8⁶, p<0.05), but not in dysthymic patients(y=0.43, p=0.25). In conclusion, we suggested that the dysthymic disorder might differ from the major depressive disorder not only in the severity of depressive symptoms but also in B-adrenergic responsiveness of lymphocytes, which was regarded as a biological marker of depressive disorder.

Keywords Major depressive disorder;Dysthymic disorder;Isoproterenol;Cyclic AMP;B-adrenoceptor.