Alkyl-ether phosphoglycerides influence calcium fluxes into human endothelial cells.
Suspended or adherent human endothelial cells (HEC) treated with 5 to 100 nM 1-O-octadecyl-2-acetyl-sn-glycero-3-phosphocholine (AGEPC, platelet-activating factor) showed a marked concentration and temperature-dependent increase in calcium uptake. This effect was also elicited by some AGEPC analogs. At 10 nM, the relative potencies were AGEPC = 100; 1-O-octadecyl-2-acetyl-sn-glycero-3-phosphoric acid (AGEPA) = 52.9; 1-O-alkyl-2-acetyl-sn-glycero-3-phosphoethanolamine (AGEPE) = 20; 1-O-octadecyl-2-deoxy-2-acetamido-sn-glycero-3-phosphocholine (2-acetamido-analog)-inactive at 100 nM = 25; 1-octadecyl-2-methoxy-sn-glycero-3-phosphocholine(2-methoxy analog)-inactive, and at 100 nM = 50. 1-O-octadecyl-2-lyso-sn-glycero-3-phosphocholine(lyso-GEPC) (100 nM) was inactive. The increase in calcium uptake was accompanied by a rise in membrane-associated calcium. The ratio between nonmembrane-bound intracellular calcium and membrane-associated calcium was constant for all agonists. CV-3988, a specific AGEPC antagonist, inhibited the effect of AGEPC. Preexposure of adherent HEC to AGEPC inhibited calcium uptake upon subsequent stimulation, suggesting a deactivation of the putative receptor. AGEPC (5 to 100 nM), but not lyso-GEPC, also stimulated calcium-efflux from calcium-preloaded, adherent HEC. AGEPC and 2-acetamido-analog, at concentrations able to induce calcium influx, did not elicit the production of 6-keto-PGF1 alpha.
Bussolino
F
F
Aglietta
M
M
Sanavio
F
F
Stacchini
A
A
Lauri
D
D
Camussi
G
G
D002118:Calcium / Q000378:metabolism*; D002448:Cell Adhesion; D004727:Endothelium / Q000378:metabolism*; D006801:Humans; D007473:Ion Channels / Q000187:drug effects*; D010714:Phosphatidylethanolamines / Q000494:pharmacology; D010742:Phospholipid Ethers; D010972:Platelet Activating Factor / Q000031:analogs & derivatives / Q000494:pharmacology*; D014471:Umbilical Veins
D007473:Ion Channels; C029271:O-deacetyl platelet activating factor; D010714:Phosphatidylethanolamines; D010742:Phospholipid Ethers; D010972:Platelet Activating Factor; C032521:acetyl glyceryl ether phosphorylethanolamine; D002118:Calcium