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Structure-Activity Relationships of the Sustained Effects of Adenosine A2A Receptor Agonists Driven by Slow Dissociation Kinetics.

Authors :
Hothersall JD
Guo D
Sarda S
Sheppard RJ
Chen H
Keur W
Waring MJ
IJzerman AP
Hill SJ
Dale IL
Rawlins PB
Source :
Molecular pharmacology [Mol Pharmacol] 2017 Jan; Vol. 91 (1), pp. 25-38. Date of Electronic Publication: 2016 Nov 01.
Publication Year :
2017

Abstract

The duration of action of adenosine A <subscript>2A</subscript> receptor (A2A) agonists is critical for their clinical efficacy, and we sought to better understand how this can be optimized. The in vitro temporal response profiles of a panel of A2A agonists were studied using cAMP assays in recombinantly (CHO) and endogenously (SH-SY5Y) expressing cells. Some agonists (e.g., 3cd; UK-432,097) but not others (e.g., 3ac; CGS-21680) demonstrated sustained wash-resistant agonism, where residual receptor activation continued after washout. The ability of an antagonist to reverse pre-established agonist responses was used as a surrogate read-out for agonist dissociation kinetics, and together with radioligand binding studies suggested a role for slow off-rate in driving sustained effects. One compound, 3ch, showed particularly marked sustained effects, with a reversal t <subscript>1/2</subscript> > 6 hours and close to maximal effects that remained for at least 5 hours after washing. Based on the structure-activity relationship of these compounds, we suggest that lipophilic N6 and bulky C2 substituents can promote stable and long-lived binding events leading to sustained agonist responses, although a high compound logD is not necessary. This provides new insight into the binding interactions of these ligands and we anticipate that this information could facilitate the rational design of novel long-acting A2A agonists with improved clinical efficacy.<br /> (Copyright © 2016 by The Author(s).)

Details

Language :
English
ISSN :
1521-0111
Volume :
91
Issue :
1
Database :
MEDLINE
Journal :
Molecular pharmacology
Publication Type :
Academic Journal
Accession number :
27803241
Full Text :
https://doi.org/10.1124/mol.116.105551