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Purpose: The α nicotinic acetylcholine receptor (nAChR) is implicated in many neuropsychiatric disorders, making it an important target for positron emission tomography (PET) imaging. The first aim of this work was to compare two α nAChRs PET radioligands, [F]ASEM (3-(1,4-diazabicyclo[3.2.2]nonan-4-yl)-6-([F]fluorodibenzo[b,d]thiophene 5,5-dioxide) and [F]DBT-10 (7-(1,4-diazabicyclo[3.2.2]nonan-4-yl)-2-([F]fluorodibenzo[b,d]thiophene 5,5-dioxide), in nonhuman primates. The second aim was to assess further the quantification and test-retest variability of [F]ASEM in humans.
Methods: PET scans with high specific activity [F]ASEM or [F]DBT-10 were acquired in three rhesus monkeys (one male, two female), and the kinetic properties of these radiotracers were compared. Additional [F]ASEM PET scans with blocking doses of nicotine, varenicline, and cold ASEM were acquired separately in two animals. Next, six human subjects (five male, one female) were imaged with [F]ASEM PET for 180 min, and arterial sampling was used to measure the parent input function. Different modeling approaches were compared to identify the optimal analysis method and scan duration for quantification of [F]ASEM distribution volume (V ). In addition, retest scans were acquired in four subjects (three male, one female), and the test-retest variability of V was assessed.
Results: In the rhesus monkey brain [F]ASEM and [F]DBT-10 exhibited highly similar kinetic profiles. Dose-dependent blockade of [F]ASEM binding was observed, while administration of either nicotine or varenicline did not change [F]ASEM V . [F]ASEM was selected for further validation because it has been used in humans. Accurate quantification of [F]ASEM V in humans was achieved using multilinear analysis with at least 90 min of data acquisition, resulting in V values ranging from 19.6 ± 2.5 mL/cm in cerebellum to 25.9 ± 2.9 mL/cm in thalamus. Test-retest variability of V was 11.7 ± 9.8%.
Conclusions: These results confirm [F]ASEM as a suitable radiotracer for the imaging and quantification of α nAChRs in humans.
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http://dx.doi.org/10.1007/s00259-017-3621-8 | DOI Listing |
Nucl Med Biol
August 2025
Department of Rehabilitation Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea. Electronic address:
Purpose: Despite its invasive and subjective nature, needle electromyography (nEMG) remains a standard method for evaluating peripheral nerve injuries. Increased alpha-7 nicotinic acetylcholine receptor (alpha7-nAChR) expression has been observed in an animal nerve injury model of muscle denervation. Hence, we used [F]ASEM positron emission tomography (PET) to investigate the temporal characteristics of alpha7-nAChR expression following skeletal muscle denervation, and tested the correlation between nerve injury severity and [F]ASEM PET uptake intensity.
View Article and Find Full Text PDFBasic Clin Pharmacol Toxicol
April 2025
Neurobiology Research Unit, Rigshospitalet, Copenhagen, Denmark.
Positron emission tomography (PET) has significantly advanced our understanding of the brain by enabling non-invasive imaging and quantification of molecular processes, including receptor binding. In this review, we explore the development and application of PET radioligands targeting the α7 nicotinic acetylcholine receptor (α7 nAChR), a receptor implicated in various central nervous system (CNS) diseases, such as Alzheimer's disease, schizophrenia and cognitive disorders. Despite challenges associated with the low density of α7 nAChRs and difficulties in achieving adequate brain penetration, several promising radioligands have been developed, including C-(R)-MeQAA, C-NS14492 and F-ASEM.
View Article and Find Full Text PDFEJNMMI Res
January 2024
Convergence Medicine Research Center, Asan Institute for Life Sciences, Asan Medical Center, Seoul, Republic of Korea.
J Neurosci
September 2023
Department of Functional Brain Imaging, National Institutes for Quantum Science and Technology, Chiba 263-8555, Japan
Chemogenetic tools provide an opportunity to manipulate neuronal activity and behavior selectively and repeatedly in nonhuman primates (NHPs) with minimal invasiveness. Designer Receptors Exclusively Activated by Designer Drugs (DREADDs) are one example that is based on mutated muscarinic acetylcholine receptors. Another channel-based chemogenetic system available for neuronal modulation in NHPs uses pharmacologically selective actuator modules (PSAMs), which are selectively activated by pharmacologically selective effector molecules (PSEMs).
View Article and Find Full Text PDFJ Nucl Med
June 2022
Department of Nuclear Medicine, University of Leipzig, Leipzig, Germany; and
As a neuromodulator, the neurotransmitter acetylcholine plays an important role in cognitive, mood, locomotor, sleep/wake, and olfactory functions. In the pathophysiology of most neurodegenerative diseases, such as Alzheimer disease (AD) or Lewy body disorder (LBD), cholinergic receptors, transporters, or enzymes are involved and relevant as imaging targets. The aim of this review is to summarize current knowledge on PET imaging of cholinergic neurotransmission in neurodegenerative diseases.
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