P2X (purinergic) receptor redistribution in rabbit aorta following injury to endothelial cells and cholesterol feeding

The redistribution of purinergic P2X receptor subunits (P2X(1) to P2X(7)) within the rabbit aorta wall three weeks after endothelial balloon injury/cholesterol feeding was examined. P2X(1) receptor cluster density was elevated in the media following balloon injury/cholesterol feeding by about 30% and these clusters appeared on smooth muscle cells throughout the greatly expanded neointima but they did not change significantly on the endothelial cells following balloon injury. P2X(4) clusters were found in high density throughout the media and in very high density in the enlarged neointima following balloon injury, particularly on the endothelial cells where the density increased about 10-fold after balloon injury. P2X(5) clusters were found in high density in the media of normal aorta but with little change following balloon injury. P2X(3), P2X(6) and P2X(7) cluster density was low in normal aorta and remained unchanged following balloon injury. All receptor subunits were found on endothelial cells. It is suggested that the release of ATP from damaged endothelial cells and from smooth muscle cells sufficient to activate P2X(4) receptors may contribute to neointimal proliferation.