ISSN:
1471-4159
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Medicine
Notes:
Abstract: 4-[18F]Fluoro-L-m-tyrosine (FMT), a biochemical probe of striatal dopaminergic function, has been synthesized as an L-3,4-di-hydroxyphenylalanine analog for positron emission tomography. Biochemical characterization of this compound in the rat 30 min after intrajugular administration indicated that in the brain, selective decarboxylation occurred in the striatum, with the formation of 4-fluoro-3-hydroxyphenylethylamine and its metabolites. Positron emission tomography analysis of brain tissue in monkeys (Macaca nemestrina) after intravenous injection of FMT revealed a true time-dependent, specific accumulation of radioactivity in striatum, with a striatum/cerebellum (nonspecific) ratio of 4 at 180 min. Peripheral metabolism accounted for 〈40% of the total radioactivity in arterial blood samples after 120 min. The amino acid remained as the major component throughout the period of investigation (n = 3; 5 min, 95%; 10 min, 85%; 30 min, 67%; 60 min, 62%; 120 min, 60%), with a plasma clearance tl/2 of 112 min. 3-O-Methylated metabolites were not observed. The substrate specificity of FMT, coupled with its limited in vivo peripheral metabolism, makes it a useful, new biochemical probe for in vivo, noninvasive evaluation of central dopaminergic mechanisms.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1471-4159.1989.tb07331.x
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