EFFECTS OF ELECTROCONVULSIVE-THERAPY ON PERIPHERAL ADRENOCEPTORS, PLASMA, NORADRENALINE, MHPG AND CORTISOL IN DEPRESSED-PATIENTS

Background, The mechanism of the antidepressant action of electroconvu lsive therapy (ECT) remains unknown Based on previous work with antide pressant drugs and their effects on the noradrenergic system, we under took this study to further determine the effects of ECT on selected in dices of peripheral adrenoceptor function in depressed patients. Metho ds. Binding parameters (B-max and K-d) of platelet alpha(2)- and leuko cyte beta(2)-adrenoceptors, plasma noradrenaline (NA) 3-methoxy-4-hydr oxy-phenylglycol (MHPG) and cortisol levels were determined in 18 pati ents, prior to treatment and 14 days after the fast of a series of ECT s, and compared with samples obtained from 18 matched control subjects . Results. Platelet alpha(2)-adrenoceptor sites were significantly ele vated in untreated patients compared with controls (P<0.03), but leuko cyte beta(2)-adrenoceptor numbers did not differ. Treatment with ECT l ed to a significant reduction in platelet alpha(2)-adrenoceptor number s, whereas leukocyte beta(2)-adrenoceptor densities increased. Pre-ECT plasma NA, MHPG, and cortisol levels were elevated in patients. compa red with controls, and decreased following ECT, but these differences were not statistically significant. Post-ECT plasma NA and beta(2)-adr enoceptor numbers were significantly. negatively correlated (P< 0.05). Conclusions. These results suggest that platelet alpha(2)-adrenocepto rs are supersensitive in depressed patients and treatment with ECT res ults in down-regulation of these receptors, which may be interpreted a s a primary therapeutic, 'normalising' effect. The post-ECT changes in leukocyte beta(2)-adrenoceptors are probably only secondary to the lo wer circulating plasma NA levels.