Effect of PPADS on P2X receptor-mediated responses of human blood vessels.

In vitro experiments showed that pyridoxal-phosphate-6-azophenyl-2',4'-disulfonic acid almost completely suppressed contractile responses of the gallbladder artery to α,β-methylene-ATP, while α,β-methylene-ATP-induced contractions of the major subcutaneous vein of patients with varicose disease did not change under the effect of the antagonist. Pyridoxal-phosphate-6-azophenyl-2',4'-disulfonic acid significantly reduced contractions of the major subcutaneous veins induced by α,β-methylene-ATP (in two highest concentrations) in patients without varicosity. These results indicate different sensitivity of human blood vessels to the studied P2 receptor agonist and antagonist.