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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 - J. Korean Med. Sci. (2010)

Bottom Line: The results were expressed as relative fluorescence intensity and fold stimulation.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Anesthesiology and Pain Medicine, Kangwon National University Medical School, Chuncheon, Korea.

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.

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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.
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Figure 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.

Mentions: The fluorescence intensity in untreated HUVECs loaded with Fluo-4 was very low and distributed homogeneously throughout the cells (Fig. 1A). Fluo-4 fluorescence in cells treated with 5 µg/mL of LPA or 1,000 µM of aminophylline increased rapidly (Fig. 1C, D). Propofol (300 µM) blocked the increase induced by LPA (5 µg/mL) (Fig. 1B). HUVECs treated with LPA (5 µg/mL) showed a very rapid increase in [Ca2+]i (Fig. 2A), but propofol blocked this increase dose-dependently at clinically relevant concentrations (10, 30 µM) (Fig. 2B).


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 - J. Korean Med. Sci. (2010)

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.
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Figure 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.
Mentions: The fluorescence intensity in untreated HUVECs loaded with Fluo-4 was very low and distributed homogeneously throughout the cells (Fig. 1A). Fluo-4 fluorescence in cells treated with 5 µg/mL of LPA or 1,000 µM of aminophylline increased rapidly (Fig. 1C, D). Propofol (300 µM) blocked the increase induced by LPA (5 µg/mL) (Fig. 1B). HUVECs treated with LPA (5 µg/mL) showed a very rapid increase in [Ca2+]i (Fig. 2A), but propofol blocked this increase dose-dependently at clinically relevant concentrations (10, 30 µM) (Fig. 2B).

Bottom Line: The results were expressed as relative fluorescence intensity and fold stimulation.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Anesthesiology and Pain Medicine, Kangwon National University Medical School, Chuncheon, Korea.

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.

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