Figure 5.

Lack of involvement of the P2Y₂ receptor in regulating AMC. (a) Cultured VSMCs and (b) aortic rings from P2Y₂R^−/− animals displayed no differences in the basal level of calcification. The inhibitory effects of (c) ATP and (d) UTP were unchanged in P2Y₂R^−/− VSMCs. (e) The selective P2Y₂ receptor antagonist, ARC118925XX, did not block the inhibitory effects of UTP on VSMC calcification. (f) Histological analysis of isolated aortas from 24-week old P2Y₂R^−/− mice showed no difference in cell morphology or the presence of AMC. Scale bar = 100 μm. The protective effects of (g) ATP and (h) UTP on cell viability were unaffected by deletion of the P2Y₂ receptor. The stimulatory actions of (i) ATP and (j) UTP on TNAP activity were unchanged in P2Y₂R^−/− VSMCs. Values are mean ± SEM (n = 6), *p < 0.05, **p < 0.01, ***p < 0.001