| Autor: |
Kawamura, Kazunori, Yui, Joji, Konno, Fujiko, Yamasaki, Tomoteru, Hatori, Akiko, Wakizaka, Hidekatsu, Fujinaga, Masayuki, Kumata, Katsushi, Yoshida, Yuichirou, Ogawa, Masanao, Nengaki, Nobuki, Yanamoto, Kazuhiko, Fukumura, Toshimitsu, Zhang, Ming-Rong |
| Jazyk: |
angličtina |
| Rok vydání: |
2012 |
| Zdroj: |
Nuclear Medicine and Biology. 39(1):89-99 |
| ISSN: |
0969-8051 |
| Popis: |
Introduction: To explore the possible use of positron emission tomography (PET) probes for imaging of I2-imidazoline receptors (I2Rs) in peripheral tissues, we labeled two new I2R ligands, 2-[2-(o-tolyl)vinyl]-4,5-dihydro-1H-imidazole (Ki for I2Rs, 3.7 nM) and 2-[2-(o-tolyl) ethyl]-4,5-dihydro-1H-imidazole (Ki for I2Rs, 1.7 nM) with 11C ([11C]metrazoline and [11C]TEIMD), respectively, and evaluated these ligands and the recently developed I2R ligand 2-[3-fluoro-[4-11C]tolyl]-4,5-dihydro-1H-imidazole ([11C]FTIMD) by in vivo studies. Methods: [11C]Metrazoline and [11C]TEIMD were prepared by a palladium-promoted cross-coupling reaction of the tributylstannyl precursor and [11C]methyl iodide. Their biodistribution in mice was investigated by tissue dissection. In addition, PET scans and metabolite analysis were performed. Results: [11C]Metrazoline and [11C]TEIMD were successfully synthesized with a suitable radioactivity for injection. In the liver and pancreas expressing I2Rs, coinjection with the high-affinity I2R ligand, BU224, induced a reduction in the radioactivity level at 30 min after injection of [11C]metrazoline and [11C]FTIMD. However, the radioactivity level after injection of [11C]TEIMD was unchanged. In the PET study, coinjection with BU224 induced a decrease in the radioactivity level in the liver and pancreas after more than 15 min of injection of [11C]metrazoline and [11C]FTIMD as compared with the results obtained for controls. In metabolite analysis, coinjection with BU224 induced a significant reduction in the percentage of unchanged [11C]metrazoline at 30 min after injection as compared with that in the control, although no significant difference was observed in the percentage of unchanged [11C]FTIMD. Conclusion: [11C]Metrazoline may be a more useful PET probe than [11C]FTIMD for imaging of I2Rs in peripheral tissues. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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