In vivo competition studies with analogues of 3-quinuclidinyl benzilate

✍ Scribed by William C. Eckelman; W. J. Rzeszotarski; R. E. Gibson; B. E. Francis; E. M. Jagoda; R. C. Reba; M. Grissom; J. Conklin; R. Eng

• Book ID: 102916183
• Publisher: John Wiley and Sons
• Year: 1984
• Tongue: English
• Weight: 684 KB
• Volume: 73
• Category: Article
• ISSN: 0022-3549
• DOI: 10.1002/jps.2600730424

✦ Synopsis

Among ligands that bind to the alpha- and beta-adrenoceptors and to the muscarinic acetylcholine receptor (m-AChR), those that bind to the latter have the best properties for external detection of receptor sites by gamma-camera imaging. To develop the optimal radiotracer, nonradioactive analogues of 3-quinuclidinyl benzilate (I) were tested in in vivo displacement studies with (-)-[3H]I to determine their ability to compete with (-)-[3H]I for the muscarinic acetylcholine receptor. There is a linear correlation between the ability to compete with (-)-[3H]I for the m-AChR and the affinity constant of the analogue as determined by in vitro assay, suggesting that the test is a valid indicator of in vivo distribution. One radioiodinated analogue, 3-quinuclidinyl p- iodobenzilate , bound to m-AChR in the heart and brain of rats.