Receptor binding at two different temperatures to discriminate agonist and antagonist behaviour of adenosine A1 receptor ligands in rat brain

Abstract— The inhibitory binding constants, Ki, at the adenosine A1 receptor in rat brain have been measured at 0 and 25°C for 25 typical ligands. The Ki ratios at the two temperatures are greater and smaller than unity for adenosine agonists and xanthine antagonists, respectively. These results suggest that two‐temperature measurements of in‐vitro Ki constants represent a simple method of discriminating between in‐vivo agonistic and antagonistic behaviour of A1 adenosine receptor ligands. 1991 Royal Pharmaceutical Society of Great Britain