EVIDENCE FOR SELECTIVE-INHIBITION BY LYSOPHOSPHATIDYLCHOLINE OF ACETYLCHOLINE-INDUCED ENDOTHELIUM-DEPENDENT HYPERPOLARIZATION AND RELAXATION IN RAT MESENTERIC-ARTERY

The effects of lysophosphatidylcholine (LPC) on acetylcholine-induced hyperpolarization and relaxation were examined in rat mesenteric arter ies. LPC (3-10 mu M) reversibly inhibited endothelium-dependent hyperp olarization by acetylcholine in a concentration-dependent manner. LPC (10 mu M) inhibited only partially endothelium-dependent relaxation by acetylcholine. However, acetylcholine-induced relaxation obtained in the presence of 100 mu M N-G-nitro-L-arginine was almost completely el iminated by 10 mu M LPC. These results indicate that LPC inhibits hype rpolarization and relaxation due to endothelium-derived hyperpolarizin g factor more specifically than the relaxation due to endothelium-deri ved nitric oxide.