Plasma noradrenaline, adrenaline and DHPG responses to clonidine in control and depressed subjects

Abstract

Plasma noradrenaline, adrenaline and DHPG were measured in depressed and control subjects before and after a challenge test with clonidine 1.3pg/kg. Significant falls in all three variables were found, but there were no differences between the two groups on either baseline or post-challenge test values. No correlation was found between these catecholamine responses to clonidine and clonidine-induced changes in growth hormone, blood pressure, or pulse rate. There were also no correlations between plasma catecholamine levels and platelet adrenergic receptor binding or plasma cortisol. These findings do not support the hypothesis of a generalized adrenergic deficit in major depressive disorder.

Differences and variability in plasma noradrenaline between depressive and anxiety disorders

“…Most of the studies are well conducted and methodological/technical differences do not apparently separate the positive and negative outcomes. Those studies that are positive tend to have a larger sample size and more melancholic patients with the exception of the study by Healy et al (1992).…”

“…Negative findings have also been reported (Sevy et al, 1989;Healy et al, 1992). Correlations between raised plasma NA and abnormalities in the hypothalamic pituitary adrenal (HPA) axis have been noted.…”