Mishina Masahiro, Ishii Kenji, Kimura Yuichi, Suzuki Masahiko, Kitamura Shin, Ishibashi Kenji, Sakata Muneyuki, Oda Keiichi, Kobayashi Shiro, Kimura Kazumi, Ishiwata Kiichi
Department of Neuro-pathophysiological Imaging, Graduate School of Medicine, Nippon Medical School, 1-396 Kosugi, Nakahara, Kawasaki, Kanagawa, 211-8533, Japan.
Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi, Tokyo, 173-0015, Japan.
Synapse. 2017 Aug;71(8). doi: 10.1002/syn.21979. Epub 2017 Apr 25.
Adenosine A receptors (A Rs) interact negatively with dopamine D receptors (D Rs) in neurons of the basal ganglia's direct pathway, while adenosine A receptors (A Rs) negatively interact with dopamine D receptors (D Rs) in indirect-pathway neurons. The aim of this study was to investigate the cerebral density of A Rs in Parkinson's disease (PD) in its early stages, using PET scans with the radioligand 8-dicyclopropylmethyl-1- C-methyl-3-propylxanthine ( C-MPDX). We studied 10 drug-naïve patients with early PD. Each patient was also examined for dopamine transporters (DATs) and D Rs by PET using C-2-β-carbomethoxy-3-β-(4-fluorophenyl)-tropane ( C-CFT) and C-raclopride ( C-RAC), respectively. Ten elderly, healthy volunteers were recruited as controls for C-MPDX PET scanning and eight elderly volunteers were recruited as controls for C-CFT and C-RAC PET scanning. The PET scans revealed a decrease in the uptake ratio index (URI) of C-CFT and an increase in the URI of C-RAC in patients. In the temporal lobe, the binding potential for C-MPDX was higher in the patient group than in healthy subjects, but not in the other regions examined, including the striatum. In patients, we observed motor-symptom asymmetry and a relationship between parkinsonism and the striatal density of DATs, but not A R density. In the putamen of early PD, asymmetrical down-regulation of A Rs is likely a compensatory mechanism in response to a decrease in dopamine. However, our study suggests that A Rs are unaltered in the putamen of early PD.
腺苷A受体（A受体）在基底神经节直接通路的神经元中与多巴胺D受体（D受体）发生负性相互作用，而腺苷A受体（A受体）在间接通路神经元中与多巴胺D受体（D受体）发生负性相互作用。本研究的目的是使用放射性配体8-二环丙基甲基-1-碳-甲基-3-丙基黄嘌呤（碳-MPDX）进行PET扫描，以研究帕金森病（PD）早期阶段A受体的脑密度。我们研究了10例未服用药物的早期PD患者。每位患者还分别使用碳-2-β-甲氧基羰基-3-β-（4-氟苯基）-托烷（碳-CFT）和碳-雷氯必利（碳-RAC）通过PET检查多巴胺转运体（DATs）和D受体。招募了10名老年健康志愿者作为碳-MPDX PET扫描的对照，8名老年志愿者作为碳-CFT和碳-RAC PET扫描的对照。PET扫描显示患者中碳-CFT的摄取率指数（URI）降低，碳-RAC的URI升高。在颞叶，患者组中碳-MPDX的结合潜能高于健康受试者，但在包括纹状体在内的其他检查区域则不然。在患者中，我们观察到运动症状不对称以及帕金森症与纹状体DATs密度之间的关系，但与A受体密度无关。在早期PD的壳核中，A受体的不对称下调可能是对多巴胺减少的一种代偿机制。然而，我们的研究表明早期PD壳核中的A受体未发生改变。
