Figure 4.

An overview the involvement of P1 receptors in arterial calcification. Activation of the A_2A receptor favors arterial calcification by stimulating intracellular cyclic adenosine monophosphate (cAMP) production. The A₃ receptor blocks arterial calcification through decreasing tissue non-specific alkaline phosphatase (TNAP) activity and cAMP production. Both A₁ and A_2B receptors might favor a phenotypic switch of vascular cells into an adipocyte phenotype and by this prevent the transdifferentiation towards a bone-like phenotype, thus halting the arterial calcification process. Dashed lines represent relevant findings in other cell-types, not yet shown in vascular cells. The term vascular cell covers vascular smooth muscle cells and valve interstitial cells.