Biochem/physiol Actions

Draflazine (R88021; (-)-R75231), is a potent nucleoside transporter ENT1 (SLC29A1) inhibitor with 370-fold selectivity over ENT2 (SLC29A2). R88021 exhibits 30- and 40-times higher affinity as (+)-R75231 (R88016) using calf lung membrane preparation (by [3H]R75231 & [3H]NBI displacement) and intact human erythrocytes (by [3H]NBMPR displacement), respectively. Draflazine is 20-times more potent as R88016 in enhancing adenosine potency against ADP-induced aggregation in human whole blood (IC50 = 0.5 µM vs 10 µM with 1 µM respective inhibitor), Draflazine and R75231, but not R88016, show cardioprotective efficacy against catecholamines infusion in rabbits in vivo.