PT - JOURNAL ARTICLE AU - Fukumitsu, Nobuyoshi AU - Ishii, Kenji AU - Kimura, Yuichi AU - Oda, Keiichi AU - Sasaki, Toru AU - Mori, Yutaka AU - Ishiwata, Kiichi TI - Adenosine A<sub>1</sub> Receptor Mapping of the Human Brain by PET with 8-Dicyclopropylmethyl-1-<sup>11</sup>C-Methyl-3-Propylxanthine DP - 2005 Jan 01 TA - Journal of Nuclear Medicine PG - 32--37 VI - 46 IP - 1 4099 - http://jnm.snmjournals.org/content/46/1/32.short 4100 - http://jnm.snmjournals.org/content/46/1/32.full SO - J Nucl Med2005 Jan 01; 46 AB - Adenosine is an endogenous modulator of synaptic functions in the central nervous system. To investigate the physiologic and pathologic roles of the adenosine receptors in the human brain, PET is a powerful in vivo technique. In this study, we quantitatively evaluated the distribution of a major subtype A1 adenosine receptor in the human brain by PET with a newly developed radioligand, 8-dicyclopropylmethyl-1-11C-methyl-3-propylxanthine (11C-MPDX). Methods: In 5 healthy volunteers, after PET measurement of the regional cerebral blood flow (rCBF) with 15O-H2O, a 60-min PET scan with 11C-MPDX was performed. The distribution volume (DV) of 11C-MPDX was quantitatively evaluated by Logan’s graphical analysis. Results: 11C-MPDX was taken up at a high level, reaching a peak at 2–2.5 min, followed by a rapid decrease. The unchanged form of 11C-MPDX in plasma was 75% at 60 min after injection. The DV of 11C-MPDX was large in the striatum and thalamus, moderate in the cerebral cortices and pons, and small in the cerebellum. The distribution pattern of 11C-MPDX in the brain was coincident with that of adenosine A1 receptors in vitro, reported previously, but discretely different from that of rCBF. Conclusion: 11C-MPDX PET has the potential for mapping adenosine A1 receptors in the human brain.