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Electroconvulsive therapy has been reported to desensitize brain beta-adrenergic receptors in rodents, but this effect has not been studied in man. We examined the effect of a course of electroconvulsive therapy on lymphocyte beta-adrenergic responsivity in 19 inpatients with melancholia. Before treatment, beta-adrenergic cyclic adenosine monophosphate response to isoproterenol was significantly blunted in the patients compared with controls. Following a course of electroconvulsive therapy, beta-adrenergic responsivity increased such that patients no longer differed from controls. Thus, blunted lymphocyte beta-adrenergic responsivity is a state-dependent effect of melancholia that can be corrected by a therapeutic course of electroconvulsive therapy. The effect of electroconvulsive therapy on this beta-adrenergic system is in the opposite direction to that reported for rodent forebrain, where electroconvulsive therapy causes desensitization, and may reflect differences between peripheral and central effects, species differences, or disease effects.

We measured regional cerebral blood flow with the xenon 133 inhalation technique in 41 patients with major depressive disorder and 40 matched, normal controls during an eyes-closed, resting condition. The depressed group had a marked reduction in global cortical blood flow. To examine topographic abnormalities, traditional multivariate analyses were applied, as well as a new scaled subprofile model developed to identify abnormal functional neural networks in clinical samples. Both approaches indicated that the depressed sample had an abnormality in topographic distribution of blood flow, in addition to the global deficit. The scaled subprofile model identified the topographic abnormality as being due to flow reduction in the depressed patients in selective frontal, central, superior temporal, and anterior parietal regions. This pattern may reflect dysfunction in the parallel distributed cortical network involving frontal and temporoparietal polymodal association areas. The extent of this topographic abnormality, as revealed by the scaled subprofile model, was associated with both patient age and severity of depressive symptoms.

Monoamine oxidase (MAO) inhibitors are effective antidepressants whose use is limited because of unwanted side effects and the possibility of a tyramine-induced hypertensive crisis (cheese reaction). (-)-Deprenyl (the official nonproprietary name for this substance is selegiline), a selective MAO type B inhibitor, may be safer and have fewer side effects, but its antidepressant efficacy is uncertain. A double-blind placebo-controlled study was carried out in depressed outpatients who were treated with (-)-deprenyl in an MAO type B selective dose range and at a higher nonselective dose range. (-)-Deprenyl did not have a statistically significant antidepressant effect after three weeks of treatment at doses of 10 mg/d. However, after six weeks and at higher doses (averaging about 30 mg/d for the second three weeks), (-)-deprenyl was superior to placebo in antidepressant effect with a positive response rate of 50% vs 13.6% and with a 41% reduction in the Hamilton Depression Rating Scale mean score vs 10% in the placebo-treated group. No hypertensive crises were seen. The rate of occurrence of side effects with (-)-deprenyl was no greater than with placebo. It was concluded that (-)-deprenyl is an effective antidepressant in a dose range where it is distinguished by the absence of many of the side effects typical of nonselective MAO inhibitors.

Previous studies of peripheral blood mononuclear cells isolated from drug-free, hospitalized patients with endogenous major depression have demonstrated a diminished adenosine 3',5'-monophosphate (cyclic AMP) response to single concentrations of isoproterenol as compared with that obtained from normal control subjects. We now report results of isoproterenol dose-response studies that indicate lower basal levels of cyclic AMP as well as diminished cyclic AMP levels in response to isoproterenol stimulation at concentrations ranging from 10(-10) to 10(-5) mol/L in drug-free, hospitalized patients with endogenous depression. The major factor responsible for the diminished cyclic AMP production in the depressed patients was a loss of receptor sites capable of cyclic AMP production. Taken together with our previously reported finding that beta-adrenergic antagonist binding was normal in peripheral blood mononuclear cells obtained from depressed patients, the results of the dose-response studies suggest a loss of receptor function (desensitization) rather than a diminished number of receptor binding sites (down-regulation) as the underlying mechanism. Potential explanations for beta-adrenergic desensitization and its implications for the catecholamine hypothesis of depressive disorders are discussed.