1 This paper describes the in vitro pharmacology of ZM 241385 (4-(2-[7-amino-2-(2-furyl) antagonized vasodilatation of the coronary bed produced by 2-chloroadenosine (2-CADO) and 2-[p-(2-carboxyethyl) phenethylamino]-5'-N-ethylcarboxamidoadenosine (CGS21680) with pA2 values of 8.57 (c.l., 8.45-8.68) and 9.02 (c.l., 8.79-9.24) respectively. 3 ZM 241385 had low potency at A2b receptors and antagonized the relaxant effects of adenosine in the guinea-pig aorta with a pA2 of 7.06, (c.l., 6.92-7.19). 4 ZM 241385 had a low affinity at A1 receptors. In rat cerebral cortex membranes it displaced tritiated R-phenylisopropyladenosine (R-PIA) with a pIC50 of 5.69 (c.l., 5.57-5.81). ZM 241385 antagonized the bradycardic action of 2-CADO in guinea-pig atria with a pA2 of 5.95 (c.l., 5.72-6.18). 5 ZM 241385 had low affinity for A3 receptors. At cloned rat A3 receptors expressed in chinese hamster ovary cells, it displaced iodinated aminobenzyl-5'-N-methylcarboxamido adenosine (AB-MECA) with a pIC50 of 3.82 (c.l., 3.67-4.06). 6 ZM 241385 had no significant additional pharmacological effects on the isolated tissues used in these studies at concentrations three orders of magnitude greater than those which block A2a receptors. At 10 gM it displayed only minor inhibition of the bradycardic effects in guinea-pig atria to some concentrations of carbachol. At 10 gM, ZM 241385 had a small inhibitory effect on relaxant effects of isoprenaline in guinea-pig aortae but no effect on sodium nitrite-induced relaxation. ZM 241385 (100 gM) was without effect on phenylephrine-induced tone in guinea-pig aortae. 7 ZM 241385 (10 gM) had no inhibitory effect on rat hepatocyte phosphodiesterase types I, II, III and IV but caused a small inhibition of the calcium calmodulin-activated type I enzyme. 8 ZM 241385 is the most selective adenosine A2a receptor antagonist yet described and is therefore a useful tool for characterization of responses mediated by A2 adenosine receptors.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.