Adenosine A1 receptor mapping of the human brain by PET with 8-dicyclopropylmethyl-1-11C-methyl-3-propylxanthine. J Nucl Med

Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan.
Journal of Nuclear Medicine (Impact Factor: 6.16). 02/2005; 46(1):32-7.
Source: PubMed


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 A(1) adenosine receptor in the human brain by PET with a newly developed radioligand, 8-dicyclopropylmethyl-1-(11)C-methyl-3-propylxanthine ((11)C-MPDX).
In 5 healthy volunteers, after PET measurement of the regional cerebral blood flow (rCBF) with (15)O-H(2)O, a 60-min PET scan with (11)C-MPDX was performed. The distribution volume (DV) of (11)C-MPDX was quantitatively evaluated by Logan's graphical analysis.
(11)C-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 (11)C-MPDX in plasma was 75% at 60 min after injection. The DV of (11)C-MPDX was large in the striatum and thalamus, moderate in the cerebral cortices and pons, and small in the cerebellum. The distribution pattern of (11)C-MPDX in the brain was coincident with that of adenosine A(1) receptors in vitro, reported previously, but discretely different from that of rCBF.
(11)C-MPDX PET has the potential for mapping adenosine A(1) receptors in the human brain.

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Available from: Kenji Ishii, Apr 23, 2015
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    • "It is important to add that a combination of neuroreceptor mapping studies with rCBF PET would help identify the effects of rCBF on neurochemical processes. It is especially important for the newly developed ligands to establish that activity-related CBF does not have a confounding effect on the ligand's specific bindings values and the distribution of the tracer does not depend on rCBF, thus validating the use of a tracer (Fukumitsu et al., 2005; Ishiwata et al., 2008). Furthermore, combined rCBF and neuroreceptor measures may help derive information about the dynamic and plastic changes in both systems. "

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