• Journal of Microbiology
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• v.40 no.3
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• pp.224-229
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• 2002

The effect of human cytomegalovirus (HCMV) on three human monocyte cell lines at different stages of differentiation was investigated. While the viability of HL-60 cells or U-937 cells was not significantly affected by HCMV infection, the viability of THP-1 cells was reduced. Acridine orange/ethidiurn bromide staining revealed that the reduction of THP-1 cell viability was due to increased apoptotic death following HCMV infection. Apoptosis in HL-60 cells was not affected by HCMV infection, and induction of apoptosis of U-937 cells by HCMV was intermediate between HL-60 and THP-1 cells. Since HL-60 cells are the least differentiated and THP-1 cells are the most differentiated, the induction of apoptosis of human monocytes appears to be related to the degree of cell differentiation. Flow cytometric and confocal microscopic studies using fluorescent calcium indicator Fluo-3 suggested a significant increase in intracellular free calcium concentration (［Ca$\^$2+/］i) in THP-1 cells undergoing apoptosis by HCMV infection. Again ［Ca$\^$2+/］i in HCMV-infected HL-60 cells was not critically altered, and that in HCMV-infected U-937 cells was intermediate between THP-1 cells and HL-60 cells. Calcium influx blockers such as verapamil and nifedipine partially reversed HCMV-induced apoptosis in THP-1 cells.

• The Korean Journal of Physiology and Pharmacology
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• v.2 no.4
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• pp.419-425
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• 1998

To clarify the effect of extracellular ATP in cultured C6 glioma cells, ATP-induced cytosolic free calcium ($[Ca^{2+}]_i$) mobilization and cell proliferation were investigated. ATP-induced $[Ca^{2+}]_i$ increased in a dose-dependent manner $(10^{-7}\;M{\sim}10^{-3}\;M)$. ATP-induced $[Ca^{2+}]_i$ increases were slightly slowed in extracellular calcium-free conditions especially in sustained phase. ATP-induced $[Ca^{2+}]_i$ increment was also inhibited by the pretreatment of U73122, a phospholipase C (PLC) inhibitor, in a time-dependent manner. Suramin, a putative $P_{2Y}$ receptor antagonist, dose-dependently weakened ATP-induced $[Ca^{2+}]_i$ mobilization. Significant increases in cell proliferation were observed at 2, 3, and 4 days after ATP was added. Stimulated cell proliferation was also observed with adenosine at days 2 and 3. This cell proliferation was significantly inhibited by the treatment with suramin. Ionomycin also stimulated cell proliferation in a concentration-dependent manner. In conclusion, we suggest that extracellular ATP stimulates C6 glioma cell proliferation via intracellular free calcium mobilization mediated by purinoceptor.

• Biomolecules & Therapeutics
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• v.15 no.2
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• pp.73-77
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• 2007

N,N-Dimethyl-D-ribo-phytosphingosine (DMPH) is an N-methyl derivative of sphingosine. In the present paper, we studied effects of DMPH on intracellular Ca$^{2+}$ concentration, pH, glutamate uptake, and cell viability in human 1321N1 astrocytes. DMPH increased intracellular Ca$^{2+}$ concentration and cytosolic pH significantly in a dose-dependent manner. DMPH also inhibited glutamate uptake by 1321N1 astrocytes. Finally, treatment of cells with DMPH for 24 h reduced viability of cells largely and concentration-dependently. In summary, DMPH increased intracellular Ca$^{2+}$ concentration and pH, inhibited glutamate uptake and evoked cytotoxicity in 1321N1 astrocytes. Our observations with DMPH in the 1321N1 astrocytes would enhance understanding of DMPH actions in the brain.

• Proceedings of the Zoological Society Korea Conference
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• 2003.08a
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• pp.160.4-160
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• 2003

No Abstract, See Full Text

• Proceedings of the Korean Biophysical Society Conference
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• 1997.07a
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• pp.17-17
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• 1997

We investigated the relationship between the voltage-operated calcium channel current and the corresponding [Ca$^{2＋}$]i change (Ca$^{2＋}$-transient) in guinea-pig gastric myocyte. Fluorescence microspectroscopy was combined with conventional whole-cell patch clamp technique and fura-2 (80 $\mu$M) was added into the CsCl-rich pipette solution.(omitted)

• Journal of fish pathology
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• v.9 no.1
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• pp.41-51
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• 1996

The present study was undertaken to investigate the physiological characteristics of the adrenergic responses in the tilapia dorsal aorta. Epinephrine, norepinephrine, clonidine and methoxamine in the presence of propranolol($3{\times}10^{-6}$M), induced only endothelium-independent and concentration-dependent vasocontractions in tilapia dorsal aorta. The rank order of potency of adrenergic agonists inducing vasocontraction was epinephrine>norepinephrine>phenylephrine>clonidine>ethoxamine, Yohimbine produced a parallel shift of the concentration-vascontraction curves of epinephrine, norepinephrine, phenylephrine and clonidine to the right, while prazosin depressed the maximum responses of epinephrine and norepinephrine. Calcium-free physiological solution and verapamil markedly reduced epinephrine or norepinephrine-induced vasocontractions. These results suggest that a-adrenergic agonists produce only on endothelium-inedpenent casoconstrictions in tilapia dorsal aorta and these effect of a-adrenergic agonists, which might be associated with both calcium release from intracellular stores and calcium influx through voltage-dependent calcium channel.

• Preventive Nutrition and Food Science
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• v.22 no.1
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• pp.9-15
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• 2017

Vaccinium angustifolium, commonly known as the lowbush blueberry, is a rich source of flavonoids, with which various human physiological activities have been associated. The present study focuses on the investigation of the effect of the methanolic extract of V. angustifolium root extract (VAE) on high affinity immunoglobulin E receptor ($Fc{\varepsilon}RI$) ${\alpha}$ chain antibody (CRA-1)-induced allergic reaction in human basophilic KU812F cells. The total phenolic content of VAE was found to be $170{\pm}1.9mg$ gallic acid equivalents/g. Flow cytometry analysis revealed that the cell surface expression of $Fc{\varepsilon}RI$ was suppressed in a concentration-dependent manner upon culture with VAE. Reverse-transcriptase polymerase chain reaction analysis showed that the mRNA level of the $Fc{\varepsilon}RI$ ${\alpha}$ chain was reduced in a concentration-dependent manner as a result of VAE treatment. Western blot analysis revealed that the protein expression of $Fc{\varepsilon}RI$ and the phosphorylation of extracellular signal-regulated kinases (ERK) 1/2 were concentration-dependently inhibited by VAE. We determined that VAE inhibited anti-CRA-1-induced histamine release, in addition to the elevation of intracellular calcium concentration ([$Ca^{2+}$]i), in a concentration-dependent manner. These results indicate that VAE may exert an anti-allergic effect via the inhibition of calcium influx and histamine release, which occurs as a result of the down-regulation of $Fc{\varepsilon}RI$ expression through inhibition of ERK 1/2 activation.

• BMB Reports
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• v.49 no.2
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• pp.128-133
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• 2016

Astrocytes play a critical role in normal brain functions and maintaining the brain microenvironment, and defects in astrocytogenesis during neurodevelopment could give rise to severe mental illness and psychiatric disorders. During neuro-embryogenesis, astrocytogenesis involves astrocytic differentiation of neural precursor cells (NPCs) induced by signals from ciliary neurotrophic factor (CNTF) or pituitary adenylate cyclase-activating peptide (PACAP). However, in contrast to the CNTF signaling pathway, the exact mechanism underlying astrocytic differentiation induced by PACAP is unknown. In the present study, we aimed to verify a signaling pathway specific to PACAP-induced astrocytogenesis, using exchange protein directly activated by cAMP2 (Epac2)-knockout mice. We found that PACAP could trigger astrocytic differentiation of NPCs via Epac2 activation and an increase in the intracellular calcium concentration via a calcium ion influx. Taken together, we concluded that astrocytogenesis stimulated by PACAP occurs through a novel signaling pathway independent from CNTF-JAK/STAT signaling, that is the well-known pathway of astrocytogenesis.

• Journal of Microbiology and Biotechnology
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• v.22 no.5
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• pp.622-627
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• 2012

Mast cells and basophils are important effector cells in immunoglobulin-E (IgE)-mediated allergic reactions. Using the human basophilic KU812F cells, we assessed the inhibitory effects of 6-methoxyluteolin, isolated from Chrysanthemum zawadskii, in the $Fc{\varepsilon}RI$-mediated allergic reaction. We determined that 6-methoxyluteolin inhibited anti-$Fc{\varepsilon}RI$ ${\alpha}$ chain antibody (CRA-1)-induced histamine release, as well as elevation of intracellular calcium concentration $[Ca^{2+}]_i$ in a dose-dependent manner. Moreover, the inhibitory effects of 6-methoxyluteolin on the cell surface expression and the mRNA level of the $Fc{\varepsilon}RI$ ${\alpha}$ chain were determined by flow cytometric analysis and reverse transcription-polymerase chain reaction (RT-PCR), respectively. Therefore, these results show that 6-methoxyluteolin is a potent inhibitor of histamine release and calcium influx via down-regulation of the $Fc{\varepsilon}RI$ ${\alpha}$ chain.

• The Korean Journal of Physiology
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• v.27 no.2
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• pp.139-150
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• 1993

We have reported that dopamine potentiates spontaneous contractions dose-dependently in guinea-pig antral circular muscle strips (Hwang et al, 1991). To clarify the underlying excitatory mechanism of dopamine on the gastric smooth muscle, the effects of dopamine on voltage-dependent $Ca^{2+}\;currents\;and\;Ca^{2+}\;-dependent\;K^+\;currents$ were observed in enzymatically dispersed guinea-pig gastric myocytes using the whole-cell voltage-clamp technique. Experiments were also done using isometric tension recording and conventional intracellular microelectrode techniques. 1) The effect of dopamine on the spontaneous contraction of antral circular muscle strips of the guinea-pig was excitatory in a dose-dependent manner, and was blocked by phentolamine, an ${\alpha}-adrenoceptor$ blocker. 2) The slow waves were not changed by dopamine. 3) The voltage-operated inward $Ca^{2+}$ current was not influenced by dopamine. 4) The $Ca^{2+}\;-dependent\;K^+$ outward current, which might reflect the changes of intracellular calcium concentration, was enhanced by dopamine. This effect was abolished by phentolamine. 5) The enhancing effect of dopamine on the $Ca^{2+}\;-dependent\;K^+$ current disappeared with heparin which is known to block the action of $InsP_3$. From these results, it is suggested that dopamine acts via $InsP_3-mediated\;Ca^{2+}$ mobilization from intracellular stores and such action potentiates the spontaneous contraction of guinea-pig gastric smooth muscle.