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Landau AM, Jakobsen S, Thomsen MB, Alstrup AKO, Orlowski D, Jacobsen J, Wegener G, Mørk A, Sørensen JCH, Doudet DJ. Combined In Vivo Microdialysis and PET Studies to Validate [ 11C]Yohimbine Binding as a Marker of Noradrenaline Release. Biomolecules 2023; 13:674. [PMID: 37189421 PMCID: PMC10136072 DOI: 10.3390/biom13040674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Revised: 04/05/2023] [Accepted: 04/07/2023] [Indexed: 05/17/2023] Open
Abstract
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.
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Affiliation(s)
- Anne Marlene Landau
- Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, A701, Palle Juul Jensens Boulevard 99, 8200 Aarhus, Denmark
- Department of Nuclear Medicine & PET-Center, Aarhus University Hospital, 8200 Aarhus, Denmark
| | - Steen Jakobsen
- Department of Nuclear Medicine & PET-Center, Aarhus University Hospital, 8200 Aarhus, Denmark
| | - Majken Borup Thomsen
- Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, A701, Palle Juul Jensens Boulevard 99, 8200 Aarhus, Denmark
- Department of Nuclear Medicine & PET-Center, Aarhus University Hospital, 8200 Aarhus, Denmark
| | | | - Dariusz Orlowski
- Center for Experimental Neuroscience (CENSE), Department of Neurosurgery, Aarhus University Hospital, 8200 Aarhus, Denmark
| | - Jan Jacobsen
- Department of Nuclear Medicine & PET-Center, Aarhus University Hospital, 8200 Aarhus, Denmark
| | - Gregers Wegener
- Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, A701, Palle Juul Jensens Boulevard 99, 8200 Aarhus, Denmark
| | - Arne Mørk
- Synaptic Transmission, H. Lundbeck A/S, Ottiliavej 9, Valby, 2500 Copenhagen, Denmark
| | | | - Doris J. Doudet
- Department of Medicine/Neurology, University of British Columbia, 2221 Wesbrook Mall, Vancouver, BC V6T 2B5, Canada;
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