[14C]Benzyl acetate is a potential radiotracer for the measurement of glial metabolism in the rat brain.
In order to develop a suitable radiotracer for the measurement of glial metabolism, we synthesized four different types of ester derivatives of [14C]acetate, namely, [14C]phenyl acetate, [14C]para-nitrophenyl acetate, [14C]2,4-dinitrophenyl acetate and [14C]benzyl acetate ([14C]BA), and evaluated their potencies in rats. Among the derivatives, the highest brain uptake at 30 s postinjection was observed for [14C]BA, which was more than 23 times higher than that of [14C]acetate itself. A long-term retention of [14C]BA radioactivity in the brain was observed, whereas rapid clearance of radioactivity was seen in the heart. [14C]BA was rapidly hydrolyzed in the intact rat brain, and less than 5% of radiolabeled parent was observed 1 min after the injection. Radiochemical analysis using thin-layer chromatography revealed that [14C]BA was rapidly converted to [14C]glutamine and [14C]glutamate in the cortex within 10 min after injection. Furthermore, the uptake of [14C]BA was significantly decreased following microinjection of fluorocitrate, a selective glial toxin. These results strongly suggest that [14C]BA may be a useful radiotracer for the measurement of glial metabolism in the intact rat brain.
Momosaki
Sotaro
S
Division of Health Sciences, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan. momosaki@sahs.med.osaka-u.ac.jp
Hosoi
Rie
R
Sanuki
Tomoya
T
Todoroki
Kenichiro
K
Yamaguchi
Masatoshi
M
Gee
Antony
A
Inoue
Osamu
O
D000818:Animals; D001593:Benzyl Compounds / Q000493:pharmacokinetics*; D001921:Brain / Q000000981:diagnostic imaging* / Q000378:metabolism*; D002250:Carbon Radioisotopes; D005240:Feasibility Studies; D008297:Male; D008657:Metabolic Clearance Rate; D009457:Neuroglia / Q000000981:diagnostic imaging* / Q000378:metabolism*; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D051381:Rats; D017208:Rats, Wistar; D014018:Tissue Distribution
D001593:Benzyl Compounds; D002250:Carbon Radioisotopes; D019275:Radiopharmaceuticals; C046412:benzyl acetate