PPADS (pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid) is a selective purinergic P2Xantagonist. It is able to block contractions of rabbit vas deferens induced by ATP or α,β,methylene-ATP. It appears to be relatively selection for P2X receptors, having no appreciable activity at α1 adrenergic, muscarinic M2 and M3, histamine H1, and adenosine A1 receptors.
^Lambrecht, G. (1992). "PPADS, a novel functionally selective antagonist of P2 purinoreceptor mediated responses". European Journal of Pharmacology217: 217–19. doi:10.1016/0014-2999(92)90877-7. PMID1330591.|accessdate= requires |url= (help)