Health & Environmental Research Online (HERO)


Print Feedback Export to File
9818742 
Journal Article 
Effects of antidepressants on the brain/plasma distribution of corticosterone 
Weber, CC; Eckert, GP; Müller, WE 
2006 
1 
Neuropsychopharmacology
ISSN: 0893-133X
EISSN: 1740-634X 
31 
11 
2443-2448 
English 
16641944 
WOS:000241380900015 
It is well established that hypothalamic-pituitary-adrenal (HPA) axis dysregulation, characterized by elevated circulating cortisol concentrations and impaired negative feedback inhibition, is associated with affective disorders. As normalization of the HPA axis function and mood-stabilizing effects occur simultaneously during antidepressant treatment, it is likely that these effects are either directly or indirectly dependent. Although data concerning the outward transport of glucocorticoids from the brain by P-glycoprotein (Pgp) are inconsistent, it has been hypothesized that antidepressants exert their clinical activity in parts by inhibiting Pgp, subsequently leading to enhanced brain glucocorticoid levels and the normalization of the HPA axis function. Here, we report on the effects of different antidepressants (amitriptyline, fluoxetine, mirtazapine, St John's wort extract) on the brain/plasma distribution of corticosterone in mice after acute and subchronic treatment. The four antidepressants exerted different effects on the corticosterone concentration in brain and plasma. Changes in corticosterone levels were highly correlated, suggesting passive diffusion between both tissues. St John's wort extract and fluoxetine elevated brain and plasma corticosterone concentrations after subchronic treatment. Mirtazapine and amitriptyline had no effect on corticosterone concentration after subchronic treatment, possibly because both are also potent antagonists at the 5-HT2 receptor, which mediates HPA axis stimulation by serotonergic stimuli. In addition, St John's wort is the only antidepressant tested which slightly elevated Pgp protein level in the brain.