Alterations of the serotonin-1A receptor (5-HT_1A) and the hypothalamic-pituitary-adrenal (HPA) axis have been reported in depression and anxiety disorders. We previously showed a strong negative correlation between cortisol plasma levels and 5-HT1A receptor binding potential (BP) in patients with social anxiety disorder but not in healthy controls using PET [1].

To investigate the relationship of cortisol and the 5-HT_1A BP in postmenopausal women, a population that is at increased risk of suffering from depressive symptoms.

Subjects: 19 postmenopausal women, aged 55.26±4.98, medication free, no current substance abuse or hormone replacement therapy.

Dynamic measurements (50 frames, 90min) were performed using the radioligand [carbonyl-11C]WAY100635 and a GE-Advance scanner. PET data were normalized to a ligand-specific template [2]. Regions-of-interest (ROI) were defined as given in [3]. TACs within ROIs were averaged and the 5-HT1A receptor BP was quantified using Logan-plot and PMOD 3.1. Measurement of total cortisol plasma levels was done using electrochemoluminescence.

We found negative correlations between cortisol and 5-HT_1A BP in the midbrain (Spearman’s r_s=−0.54, p=0.02), the median raphe nucleus (r_s=−0.47, p=0.04) and the nucleus accumbens (r_s=−0.505, p=0.03).

In line with our previous findings [1], the observed negative association between cortisol plasma levels and 5-HT1A BP might reflect an increased vulnerability for mood disorders in postmenopausal women.