J Korean Med Sci.  2010 Aug;25(8):1222-1227. 10.3346/jkms.2010.25.8.1222.

Propofol and Aminophylline Antagonize Each Other During the Mobilization of Intracellular Calcium in Human Umbilical Vein Endothelial Cells

• Son HJ
• Lim YC
• Ha KS
• Kang SS
• Cheong IY
• Lee SJ
• Park SW
• Hwang BM

• KMID: 1714047
• DOI: http://doi.org/10.3346/jkms.2010.25.8.1222

Abstract

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.

Keyword

Aminophylline; Calcium; Lysophosphatidic Acid; Propofol

MeSH Terms

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

Figure

• 

  Fig. 1 Fluorescence of intracellular calcium in human umbilical-vein endothelial cells (HUVECs) incubated with Fluo-4 and detected by a fluorescence spectrophotometer (confocal microscope). (A) Control group (resting cells) before treatment. (B) Preincubation with propofol (300 µM) blocks lysophosphatidic acid (LPA) signals. (C) Aminophylline (1,000 µM) treatment increases Fluo-4 fluorescence. (D) LPA (5 µg/mL) increases Fluo-4 fluorescence.

• 

  Fig. 2 Propofol inhibits lysophosphatidic acid (LPA)-induced intracellular calcium ([Ca2+]i) elevation. (A) Levels of [Ca2+]i generated by propofol. Cells preincubated in propofol for 30 min and treated with LPA (5 µg/mL). Serum-starved HUVECs were loaded with 2 µM of Fluo-4 for 40 min. Results are expressed as relative fluorescence intensity (RFI). Each trace is of a single cell and is representative of at least three independent experiments. Intracellular Ca2+ was monitored by confocal microscopy. P10 µM→LPA (S): incubation with propofol (10 µM) for 30 min and then treatment with LPA (5 µg/mL); P30 µM→LPA (S): incubation with propofol (30 µM) for 30 min and then treatment with LPA (5 µg/mL); P100 µM→LPA (S): incubation with propofol (100 µM) for 30 min and then treatment with LPA (5 µg/mL); P1,000 µM→LPA (S): incubation with propofol (1,000 µM) for 30 min and then treatment with LPA (5 µg/mL). (B) Propofol inhibits LPA-induced [Ca2+]i elevation in a dose-dependent manner. Values represent the mean peak intracellular calcium response. Results are expressed as fold-stimulation, determined by comparing RFIs before stimulation and expressed as mean±SD from three separate determinations. Each determination represents the mean of at least 10 cells.

• 

  Fig. 3 Representative trace of intracellular calcium ([Ca2+]i) induced by drugs. (A) The elevation of [Ca2+]i generated by aminophylline treatment in HUVECs. Serum-starved HUVECs were loaded with 2 µM of Fluo-4 for 40 min. Results are expressed as relative fluorescence intensity (RFI). Each trace is of a single cell and is representative of at least three independent experiments. Intracellular Ca2+ was monitored by confocal microscopy. A, aminophylline; P, propofol; LPA, lysophosphatidic acid; (s), treatment. (B) Levels of mean peak [Ca2+]i generated by various concentrations of aminophylline in HUVECs. Aminophylline generates [Ca2+]i elevation in a dose-dependent manner. Values represent the mean peak intracellular calcium response. Results are expressed as fold-stimulation, determined by comparing RFIs before stimulation and expressed as mean±SD from three separate determinations. Each determination represents the mean of at least 10 cells.

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  Fig. 4 Levels of mean peak intracellular calcium ([Ca2+]i) generated by lysophosphatidic acid (LPA) or aminophylline treatment after incubation with propofol (10, 30 µM) for 30 min. (A) Levels of mean peak intracellular calcium ([Ca2+]i) generated by lysophosphatidic acid (LPA) or aminophylline treatment after incubation with propofol (10 µM) and for 30 min. LPA only: treatment with LPA (5 µg/mL); P10→LPA: incubation with propofol (10 µM) and treatment with LPA (5 µg/mLl); A100 only: treatment with aminophylline (100 µM); P10→A100: incubation with propofol (10 µM) and treatment with aminophylline (100 µM) Values represent the mean peak intracellular calcium response. Results are expressed as fold-stimulation, determined by comparing relative fluorescence intensities (RFI) before stimulation and expressed as mean±SD from three separate determinations. Each determination represents the mean of at least 10 cells. (B) Levels of mean peak intracellular calcium ([Ca2+]i) generated by lysophosphatidic acid (LPA) or aminophylline treatment after incubation with propofol (30 µM) and for 30 min. LPA only: treatment with LPA (5 µg/mL); P30→LPA: incubation with propofol (30 µM) and treatment with LPA (5 µg/mL); A100 only: treatment with aminophylline (100 µM); P30→A100: incubation with propofol (30 µM) and treatment with aminophylline (100 µM) Values represent the mean peak intracellular calcium response. Results are expressed as fold-stimulation, determined by comparing relative fluorescence intensities (RFI) before stimulation and expressed as mean±SD from three separate determinations. Each determination represents the mean of at least 10 cells. *P<0.05 compared with treatment with LPA (5 µg/mL); †P<0.05 compared with treatment with aminophylline (100 µM).

• 

  Fig. 5 Levels of mean peak intracellular calcium ([Ca2+]i) generated by lysophosphatidic acid (LPA) treatment after incubation with propofol (30 µM) and aminophylline for 30 min. LPA (S): treatment with LPA (5 µg/mL); P30→LPA (S): incubation with propofol (30 µM) and treatment with LPA (5 µg/mL); P30+A100→LPA (S): incubation with propofol (30 µM) and aminophylline (100 µM) and treatment with LPA (5 µg/mL); P30+A1000→LPA (S): incubation with propofol (30 µM) and aminophylline (1,000 µM) and treatment with LPA (5 µg/mL). Values represent the mean peak intracellular calcium response. Results are expressed as fold-stimulation, determined by comparing relative fluorescence intensities (RFI) before stimulation and expressed as mean±SD from three separate determinations. Each determination represents the mean of at least 10 cells. *P<0.05 compared with propofol (30 µM)-incubated cells; †P<0.05 compared with propofol (30 µM) and aminophylline (100 µM)-incubated cells.

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