Alteration of calcium mobilization in endothelial cells by volatile anesthetics

Halothane and isoflurane have different effects on the peripheral vasculature. Halothane decreases blood pressure primarily by decreasing cardiac contractility, whereas isoflurane acts primarily as a peripheral vasodilator. These peripheral vascular actions may result from different effects of the anesthetics on endothelial cell function and the release of endothelium-derived vasoactive mediators. The ability of these agents at clinically relevant concentrations to alter agonist-induced calcium mobilization in single cultured bovine aortic endothelial cells was tested using the fluorescent indicator fura-2. Neither halothane (0.3, 0.5, and 2 mM) or isoflurane (0.5 and 2 mM) altered basal calcium ([Ca]i = 49 +/- 5 nM); however, the calcium transient normally elicited by 10 nM bradykinin (peak [Ca]i = 307 +/- 22 nM) was inhibited significantly by halothane but not isoflurane. Neither anesthetic altered the calcium response to ATP (10 microM). These findings suggest that anesthetics may have specific effects on receptor-mediated endothelial cell functions that could influence hemodynamics.