{"title":"TRIFUNCTIONAL LIGANDS: A RADIOIODINATED HIGH AFFINITY ACYLATING ANTAGONIST FOR THE A<sub>1</sub> ADENOSINE RECEPTOR.","authors":"Kenneth A Jacobson, Mark E Olah, Gary L Stiles","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>A new xanthine (adenosine antagonist) radioligand that binds covalently to A<sub>1-</sub>adenosine receptors was prepared and used as a receptor probe. BH-DITC-XAC was synthesized via a trifunctional aryl diisothiocyanate crosslinker. containing the p-hydroxyphenylpropionyl group for radioiodination. The xanthine competed against agonist or antagonist A<sub>1</sub> receptor radioligands in bovine brain membranes with an IC<sub>50</sub>, of 40nM. <sup>125</sup>I-BH-DITC-XAC, prepared directly by the chloramine T method and purified by HPLC. bound specifically to A<sub>1</sub> receptors. This binding was inhibited in the presence of the adenosine agonists <i>R</i>-PIA, <i>S</i>-PIA. and NECA in a dose dependent manner and with the order of potency characteristic of bovine A<sub>1</sub> receptors. Incubation of affinity purified bovine A<sub>1</sub>-receptors with <sup>125</sup>I-BH-DITC-XAC (0.8 nM) for 2 hours resulted in the specific and clean labelling of a polypeptide band corresponding to MW 36,000, identical to that previously found for the A<sub>1</sub> receptor.</p>","PeriodicalId":90677,"journal":{"name":"Pharmacology communications","volume":"1 2","pages":"145-154"},"PeriodicalIF":0.0,"publicationDate":"1992-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4217529/pdf/nihms385194.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"32795641","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}