Combined In Vivo Microdialysis and PET Studies to Validate [11C]Yohimbine Binding as a Marker of Noradrenaline Release

Autor: Anne Marlene Landau, Steen Jakobsen, Majken Borup Thomsen, Aage Kristian Olsen Alstrup, Dariusz Orlowski, Jan Jacobsen, Gregers Wegener, Arne Mørk, Jens Christian Hedemann Sørensen, Doris J. Doudet
Jazyk: angličtina
Rok vydání: 2023
Předmět:
Zdroj: Biomolecules, Vol 13, Iss 4, p 674 (2023)
Druh dokumentu: article
ISSN: 2218-273X
DOI: 10.3390/biom13040674
Popis: The noradrenaline system attracts attention for its role in mood disorders and neurodegenerative diseases but the lack of well-validated methods impairs our understanding when assessing its function and release in vivo. This study combines simultaneous positron emission tomography (PET) and microdialysis to explore if [11C]yohimbine, a selective antagonist radioligand of the α2 adrenoceptors, may be used to assess in vivo changes in synaptic noradrenaline during acute pharmacological challenges. Anesthetised Göttingen minipigs were positioned in a head holder in a PET/CT device. Microdialysis probes were placed in the thalamus, striatum and cortex and dialysis samples were collected every 10 min. Three 90 min [11C]yohimbine scans were acquired: at baseline and at two timepoints after the administration of amphetamine (1–10 mg/kg), a non-specific releaser of dopamine and noradrenaline, or nisoxetine (1 mg/kg), a specific noradrenaline transporter inhibitor. [11C]yohimbine volumes of distribution (VT) were obtained using the Logan kinetic model. Both challenges induced a significant decrease in yohimbine VT, with time courses reflecting their different mechanisms of action. Dialysis samples revealed a significant increase in noradrenaline extracellular concentrations after challenge and an inverse correlation with changes in yohimbine VT. These data suggest that [11C]yohimbine can be used to evaluate acute variations in synaptic noradrenaline concentrations after pharmacological challenges.
Databáze: Directory of Open Access Journals
Nepřihlášeným uživatelům se plný text nezobrazuje