STRUCTURAL DIFFERENCES IN THE ABILITY OF LYSOPHOSPHOLIPIDS TO INHIBITENDOTHELIUM-DEPENDENT HYPERPOLARIZATION BY ACETYLCHOLINE IN RAT MESENTERIC-ARTERIES

The effects of different lysophospholipids on endothelium-dependent hy perpolarization by acetylcholine were examined in rat mesenteric arter ies. Lysophosphatidylcholine with 14 or longer carbon acyl chain signi ficantly inhibited the hyperpolarization, while that with 12 or lesser carbon acyl chain was without effect. Lysophosphatidylcholine with un saturated acyl chain also showed a potent inhibition. Lysophosphatidyl inositol and lyse-platelet activating factor, but not phosphatidylchol ine, lysophosphatidic acid, lysophosphatidylethanolamine or lysophosph atidylserine, suppressed the hyperpolarization. These results suggest that the length of the carbon acyl chain and the size of the polar hea d group may be crucial for the effects of lysophospholipids on endothe lium-dependent hyperpolarization. Accumulation of these lysophospholip ids may play an important role in endothelial dysfunction associated w ith atherosclerosis. (C) 1996 Academic Press, Inc.