AF-353 is a noncompetitive dual antagonist of the purinoreceptors P2X3 and P2X2/3 (IC50s = 10 and 79.4 nM, respectively). It is selective for P2X3 and P2X2/3 over P2X1, P2X2, P2X4, P2X5, and P2X7 (IC50 = >10 μM for all). It inhibits calcium flux in CHO-K1 cells expressing the rat P2X3 receptor and in 1321N1 cells expressing the human P2X3 and P2X2/3 receptors (IC50s = 8.91, 8.71, and 38.9 nM, respectively). AF-353 decreases the electrical signals in the detrusor, but not striated, muscle of the bladder in female rats.
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