Abstract
The vesamicol analogue (+/-)-trans-2-Hydroxy-3-[4-(3-iodophenyl)piperidyl]-1,2,3,4-tetrahydronaphthalene (3'-IBVM), a potent ligand for the vesicular acetylcholine transporter (VAChT), was evaluated as a potential radiotracer for studying VAChT density in vivo. In radioligand binding experiments, 3'-IBVM displays subnanomolar affinity for VAChT and 100-fold selectivity for VAChT over sigma1 and sigma2 receptors. Consistent with this profile, radioiodinated (+/-)-3'-IBVM distributed heterogenously in the rat brain following a bolus IV injection, displaying high concentrations in the striatum and moderate to low concentrations in the cortex and cerebellum, respectively. However, co-injection of the radiotracer with the sigma ligand haloperidol resulted in significant reductions of radiotracer levels in all brain regions examined. Therefore, radioiodinated (+/-)-IBVM appears to bind to both VAChT and sigma receptors in vivo.
Publication types
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Acetylcholine / metabolism*
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Animals
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Autoradiography
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Binding, Competitive
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Brain / diagnostic imaging
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Brain / metabolism
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Carrier Proteins / metabolism*
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Guinea Pigs
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In Vitro Techniques
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Iodine Radioisotopes
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Isotope Labeling
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Ligands
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Liver / metabolism
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Membrane Transport Proteins*
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Piperidines / chemical synthesis*
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Piperidines / chemistry
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Piperidines / metabolism
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Protein Binding
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Radionuclide Imaging
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Radiopharmaceuticals / chemical synthesis*
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Radiopharmaceuticals / chemistry
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Radiopharmaceuticals / metabolism
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Rats
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Rats, Wistar
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Receptors, sigma / metabolism
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Synaptic Vesicles / metabolism*
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Tissue Distribution
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Torpedo
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Vesicular Acetylcholine Transport Proteins
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Vesicular Transport Proteins*
Substances
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3'-iodobenzovesamicol
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Carrier Proteins
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Iodine Radioisotopes
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Ligands
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Membrane Transport Proteins
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Piperidines
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Radiopharmaceuticals
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Receptors, sigma
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Slc18a3 protein, rat
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Vesicular Acetylcholine Transport Proteins
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Vesicular Transport Proteins
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Acetylcholine