Lysophosphatidylcholine-induced vascular relaxation and production of cGMP are mediated by endothelium-derived...

Endothelial cells produce powerful vasorelaxant substances, among them an endothelium-derived relaxing factor that is believed to be nitric oxide. It relaxes vascular smooth muscle via activation of guanylate cyclase and a subsequent rise in cyclic GMP level. Lysophosphatidylcholine is a potent endothelium-dependent vascular smooth muscle relaxant. Its action, similar to that of endothelium-derived relaxing factor, mediates an increase of cGMP in smooth muscle cells. The experiments reported here demonstrate that inhibitors of nitric oxide formation, such as N-omega-nitro-L-arginine and its methyl ester, inhibit relaxation and cyclic GMP formation by lysophosphatidylcholine in bovine pulmonary artery strips with intact endothelium in a dose-dependent manner. N-omega-Nitro-D-arginine methyl ester does not inhibit relaxation; L-arginine, but not D-arginine, reverses the effect of N-omega-nitro-L-arginine and its methyl ester. It is concluded that lysophosphatidylcholine-induced endothelium-dependent vasorelaxation is endothelium-derived relaxing factor-mediated.