This study examined whether propofol and aminophylline affect the mobilization of intracellular calcium in human umbilical vein endothelial cells. Intracellular calcium was measured using laser scanning confocal microscopy. Cultured and serum-starved cells on round coverslips were incubated with propofol or aminophylline for 30 min, and then stimulated with lysophosphatidic acid, propofol and aminophylline. The results were expressed as relative fluorescence intensity and fold stimulation. Propofol decreased the concentration of intracellular calcium, whereas aminophylline caused increased mobilization of intracellular calcium in a concentration-dependent manner. Propofol suppressed the lysophosphatidic acid-induced mobilization of intracellular calcium in a concentration-dependent manner. Propofol further prevented the aminophylline-induced increase of intracellular calcium at clinically relevant concentrations. However, aminophylline reversed the inhibitory effect of propofol on the elevation of intracellular calcium by lysophosphatidic acid. Our results suggest that propofol and aminophylline antagonize each other on the mobilization of intracellular calcium in human umbilical vein endothelial cells at clinically relevant concentrations. Serious consideration should be given to how this interaction affects mobilization of intracellular calcium when these two drugs are used together.
Aminophylline/*antagonists & inhibitors/pharmacology ; Anesthetics, Intravenous/*antagonists & inhibitors/pharmacology ; Bronchodilator Agents/*antagonists & inhibitors/pharmacology ; Calcium/*metabolism ; Cells, Cultured ; Endothelial Cells/*drug effects/metabolism ; Endothelium, Vascular/cytology ; Humans ; Lysophospholipids/pharmacology ; Microscopy, Confocal ; Propofol/*antagonists & inhibitors/pharmacology ; Umbilical Veins/cytology