Potential of [11C]TMSX for the evaluation of adenosine A2A receptors in the skeletal muscle by positron emission tomography.
We examined the potential of [7-methyl-11C]-(E)-8-(3,4,5-trimethoxystyryl)-1,3,7-trimethylxanthine ([11C]TMSX) for the assessment of adenosine A2A receptors in muscle. In rodents, specific binding of [11C]TMSX was observed in muscle and heart by blockade with A2A-selective CSC and non-selective theophylline, but not with A1-selective DPCPX. Swimming exercise fluctuated radioligand-receptor binding in these tissues. In a PET study of two subjects, theophylline-infusion slightly deceased the distribution volume of [11C]TMSX in the heart (20% reduction) and muscle (10% reduction), which suggested the specific binding.
Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, 1-1 Naka-cho, Itabashi-ku, Tokyo 173-0022, Japan. ishiwata@pet.tmig.or.jp
Kiichi
K
Ishiwata
Masaki
M
Mizuno
Yuichi
Y
Kimura
Kazunori
K
Kawamura
Keiichi
K
Oda
Toru
T
Sasaki
Yoshio
Y
Nakamura
Isao
I
Muraoka
Kenji
K
Ishii
D000328:Adult; D000818:Animals; D005240:Feasibility Studies; D006801:Humans; D008297:Male; D008657:Metabolic Clearance Rate; D051379:Mice; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging* / Q000378:metabolism*; D009928:Organ Specificity; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals / Q000138:chemical synthesis / Q000493:pharmacokinetics; D051381:Rats; D043705:Receptor, Adenosine A2A / Q000378:metabolism*; D013550:Swimming / Q000502:physiology*; D014018:Tissue Distribution; D014970:Xanthines / Q000493:pharmacokinetics*
C405422:KF18446; D019275:Radiopharmaceuticals; D043705:Receptor, Adenosine A2A; D014970:Xanthines