Journal of Nuclear Medicine
September 29, 2022
Tudor M. Ionescu, Mario Amend, Tadashi Watabe et al.
19 citations
MDMA triggers neuronal activation in limbic projection areas involved in emotional processing, shown by localized increases in glucose metabolism measured with 18F-FDG fPET. Simultaneously, it causes global cerebral and extracerebral hemodynamic decreases detected by BOLD fMRI. The hemodynamic reductions strongly correlate with serotonin transporter occupancy and are of a nonneuronal, peripheral origin. Increased serotonin from SERT blockage leads to neurovascular uncoupling via direct vascular effects. These findings challenge interpretations of previous fMRI studies that suggested MDMA mainly inhibits brain activity, and recommend 18F-FDG fPET as a more robust measure for pharmacological research on psychedelics.
eLife
May 15, 2025
Tudor M Ionescu, Mario Amend, Rakibul Hafiz et al.
1 citation
A novel imaging technique called molecular connectivity (MC) combines functional magnetic resonance imaging (fMRI) and positron emission tomography (PET) to map how specific molecules, such as the serotonin transporter, interact across brain regions. Using dynamic [11C]DASB PET scans in rats, the study examined changes in serotonin transporter distribution after a single dose of MDMA (ecstasy). Results showed clear alterations in molecular connectivity following MDMA, directly linking drug effects on serotonin transporter occupancy to changes in functional brain networks. This approach provides a comprehensive view of brain function at the molecular level and offers new ways to understand how drugs modulate brain activity.
bioRxiv Preprint Server
February 14, 2022
Tudor M. Ionescu, Mario Amend, Tadashi Watabe et al.
1 citation
preprint
MDMA, a psychedelic compound being tested for treating post-traumatic stress disorder, inhibits brain activity rather than exciting it, according to fMRI studies. However, interpreting these hemodynamic changes is complicated by MDMA's potent vascular effects. This study used simultaneous PET/fMRI in rats to relate BOLD-fMRI hemodynamic changes to glucose utilization and serotonin transporter occupancy measured by [18F]FDG fPET and [11C]DASB PET. The findings help clarify how MDMA affects brain function, challenging earlier assumptions of mainly excitatory effects.