Protamine induces elevation of cytosolic free Ca2+ in cultured porcine aortic endothelial cells.
To test the hypothesis that protamine influences calcium movement in endothelial cells, we measured the concentration of intracellular free calcium ([Ca2+]i) in cultured porcine aortic endothelial (PAE) cells in Krebs solution (2.5mM Ca2+, pH 7.4) at 37 degrees C, by fura-2 fluorimetry. The basal [Ca2+]i of PAE cells was 113+/-18 nM (n=6). Protamine increased [Ca2+]i in a concentration-dependent manner (EC50, the concentration having 50% of the maximum effect, 1.4+/-0.3 microg mL(-1), n=6). The response of PAE cells to 100 microg mL(-1) protamine (330+/-80 nM, n=6) was blocked by a Ca2+ chelator, 5 mM glycoletherdiaminetetraacetic acid (EGTA; 131+/-16 nM, n=6), and by a non-selective Ca2+ channel blocker, 3 mM Co2+ (134+/-14 nM, n=6). These results suggest that Ca2+ influx through cell-membrane Ca2+ channels is mainly responsible for the protamine-induced Ca2+ elevation.
Sato
N
N
Department of Anaesthesiology and Critical Care Medicine, Hiroshima University, School of Medicine, Japan.
Az-Ma
T
T
Fujii
K
K
Yuge
O
O
D000818:Animals; D001011:Aorta / Q000187:drug effects / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D018929:Cell Culture Techniques; D002614:Chelating Agents / Q000494:pharmacology; D003600:Cytosol / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004533:Egtazic Acid / Q000494:pharmacology; D004727:Endothelium / Q000187:drug effects / Q000378:metabolism*; D011479:Protamines / Q000494:pharmacology*; D013552:Swine
D002614:Chelating Agents; D011479:Protamines; D004533:Egtazic Acid; D002118:Calcium