Abstract

Endothelium-denuded coronary artery was reseeded with the endothelial cells in culture, and the endothelium-dependent responses were compared with those in arteries with or without native endothelium. A23187 produced a relaxation in the arterial preparations reseeded with cultured endothelial cells in the cell suspension of 10(5) cells/ml for 17 to 19 hr, whereas no relaxation was observed in the denuded artery. Relaxing response to Ca++ ionophore A23187 was dependent on the number of endothelial cells reseeded. The A23187-induced relaxation in the cell-reseeded artery was inhibited markedly by pretreatment with 3 x 10(-4) M NG-monomethyl-L-arginine or 5 x 10(-5) M methylene blue, but not 10(-4) M aspirin. NG-monomethyl-L-arginine (3 x 10(-4) M) and methylene blue (5 x 10(-5) M) produced a contraction in the cell-reseeded artery. Contraction evoked by bradykinin in the denuded arteries was attenuated by reseeding endothelial cells. KCl-induced contraction in the endothelium-reseeded artery did not differ from that in the denuded artery. Contractile responses to norepinephrine and serotonin were attenuated by reseeding endothelial cells onto the denuded artery to a small extent. Scanning electron microscopy showed that the luminal surface of endothelium-reseeded arteries was partly covered with endothelial cells. We conclude that when the cultured endothelial cells are reseeded onto a denuded coronary artery, endothelium-derived relaxing factor release occurs, but endothelium-dependent mechanisms are not the same as those for native cells.