Widespread increases of cortical serotonin type 2A receptor availability after hormone therapy in euthymic postmenopausal women

Abstract

Objective To use statistical parametric mapping to determine the extent of previously reported serotonin type 2A (5HT 2A) receptor binding potential (BP) increases in postmenopausal women following hormone therapy. Design Repeated measures positron emission tomography (PET) study. Setting Academic research environment. Patient(s) Five healthy, postmenopausal women. Intervention(s) Serial PET images of [ 18F]altanserin uptake were acquired to measure 5HT 2A receptor BP at menopausal baseline, following estradiol (E 2), and following combined E 2 + micronized progesterone (P 4). Main outcome measure(s) 5HT 2A receptor BP. Result(s) Combined E 2 + P 4 treatment was associated with significant increases in the 5HT 2A receptor BP increases in widespread areas of cerebral cortex. Treatment with E 2 alone was also associated with widespread cortical BP increases, although these changes reached statistical significance in fewer regions. The rate of [ 18F]altanserin metabolism was significantly decreased in the E 2 + P 4 condition relative to menopausal baseline, but this difference did not appear to correlate with changes in 5HT 2A receptor BP. Conclusion(s) Estradiol priming followed by combined E 2 + P 4 is associated with widespread increases in 5HT 2A receptor BP in the cerebral cortex, consistent with the E 2-associated increases in 5HT 2A receptor density previously observed in experimental animals.