Cytosolic [Ca super(2+)] measurements in endothelium of rabbit cardiac valves using imaging fluorescence microscopy

Cytosolic Ca super(2+) plays a critical role in the secretion of endothelium-derived factors. A new preparation that allows fluorescence imaging of intracellular free Ca super(2+) concentration ([Ca super(2+)] sub(i)) in endothelial cells of rabbit cardiac valves is described. Electron micrographs of the valves revealed no underlying smooth muscle cells that might influence endothelial cell responses or contribute to [Ca super(2+)] sub(i) signaling. The valve leaflets, which were