Fate of tritiated 6-fluorodopamine in rats: A false neurotransmitter for positron emission tomographic imaging of sympathetic innervation and function

Journal Article · Thu Nov 01 00:00:00 EST 1990 · Journal of Pharmacology and Experimental Therapeutics; (USA)

OSTI ID:6273427

Chang, P C; Szemeredi, K; Grossman, E; Kopin, I J; Goldstein, D S ^[1]

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1. National Institute of Neurological Disorders and Stroke, Bethesda, MD (USA)

In evaluating positron-emitting analogs of dopamine (DA) as imaging agents for visualizing tissue sympathetic innervation and function, we assessed the metabolic fate of systemically injected ({sup 3}H)-6-fluorodopamine (({sup 3}H)-6F-DA) in plasma, in sympathetically innervated tissues (left ventricle, spleen and salivary glands) and in excretory organs (liver and kidney) of rats. By 5 min after intravenous bolus injection of a physiologically inactive amount (450 ng, 10 microCi) of ({sup 3}H)-6F-DA, {sup 3}H was concentrated in all the organs compared with that in blood or plasma. In the sympathetically innervated organs, most of the radioactivity was in ({sup 3}H)-6F-DA and ({sup 3}H)-6-fluoronorepinephrine (( {sup 3}H)-6F-NE), whereas in the blood, plasma and excretory organs most of the radioactivity was in noncatechol compounds such as O-methylated and conjugated metabolites. In sympathetically innervated organs, tissue/blood ratios exceeded 1.0 at all time points between 5 and 120 min after injection of ({sup 3}H)-6F-DA and increased progressively (from 8 to 60 in myocardium), whereas the tissue/blood ratios in the kidney and liver increased by less than 2-fold during this interval. In all the studied tissues, the proportion of total tissue {sup 3}H that was due to ({sup 3}H)F-NE increased progressively while that due to ({sup 3}H)F-DA declined, consistent with conversion of ({sup 3}H)F-DA to ({sup 3}H)F-NE in vesicles in sympathetic nerve endings.

• OSTI ID: 6273427
• Journal Information: Journal of Pharmacology and Experimental Therapeutics; (USA), Vol. 255:2; ISSN 0022-3565
• Country of Publication: United States
• Language: English

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62 RADIOLOGY AND NUCLEAR MEDICINE
AUTONOMIC NERVOUS SYSTEM
POSITRON COMPUTED TOMOGRAPHY
DOPAMINE
METABOLISM
IMAGE PROCESSING
METABOLITES
RATS
TISSUE DISTRIBUTION
TRACER TECHNIQUES
TRITIUM COMPOUNDS
AMINES
ANIMALS
AROMATICS
AUTONOMIC NERVOUS SYSTEM AGENTS
CARDIOTONICS
CARDIOVASCULAR AGENTS
COMPUTERIZED TOMOGRAPHY
DIAGNOSTIC TECHNIQUES
DISTRIBUTION
DRUGS
EMISSION COMPUTED TOMOGRAPHY
HYDROGEN COMPOUNDS
HYDROXY COMPOUNDS
ISOTOPE APPLICATIONS
MAMMALS
NERVOUS SYSTEM
NEUROREGULATORS
ORGANIC COMPOUNDS
PHENOLS
POLYPHENOLS
PROCESSING
RODENTS
SYMPATHOMIMETICS
TOMOGRAPHY
VERTEBRATES
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