Protamine induces elevation of cytosolic free Ca2+ in cultured porcine aortic endothelial cells

• Published in: Journal of pharmacy and pharmacology Vol. 51; no. 8; p. 949
• Main Authors: Sato, N, Az-Ma, T, Fujii, K, Yuge, O
• Format: Journal Article
• Language: English
• Published: England 01.08.1999
• Subjects: Animals; Aorta - drug effects; Aorta - metabolism; Calcium - metabolism; Cell Culture Techniques; Chelating Agents - pharmacology; Cytosol - metabolism; Dose-Response Relationship, Drug; Drug Interactions; Egtazic Acid - pharmacology; Endothelium - drug effects; Endothelium - metabolism; Protamines - pharmacology; Swine
• ISSN: 0022-3573
• DOI: 10.1211/0022357991773212

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.