• Proceedings of the Korean Biophysical Society Conference
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• 2002.06b
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• pp.35-35
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• 2002

The large conductance $Ca^{2＋}$ -activated $K^{＋}$ channels ($BK_{Ca}$) in vascular smooth muscle have been considered to function as a negative feedback in pressure-induced vasoconstriction. In the present study, the function of cytoskeletons in the regulation of $BK_{Ca}$ and its stretch sensitivity was investigated. Using the inside-out patch clamp technique, we recorded single channel activities of $BK_{Ca}$ with 150 mM KCl in the bath solution (pCa=6.5).(omitted)itted)

• The Korean Journal of Physiology and Pharmacology
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• v.15 no.5
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• pp.279-283
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• 2011

Quercetin (3,3',4',5,7-pentahydroxyflavone) is an attractive therapeutic flavonoid for cancer treatment because of its beneficial properties including apoptotic, antioxidant, and antiproliferative effects on cancer cells. However, the exact mechanism of action of quercetin on ion channel modulation is poorly understood in bladder cancer 253J cells. In this study, we demonstrated that large conductance $Ca^{2+}$-activated $K^+$ ($BK_{Ca}$) or MaxiK channels were functionally expressed in 253J cells, and quercetin increased $BK_{Ca}$ current in a concentration dependent and reversible manner using a whole cell patch configuration. The half maximal activation concentration ($IC_{50}$) of quercetin was $45.5{\pm}7.2{\mu}m$. The quercetin-evoked $BK_{Ca}$ current was inhibited by tetraethylammonium (TEA; 5 mM) a non-specific $BK_{Ca}$ blocker and iberiotoxin (IBX; 100 nM) a $BK_{Ca}$-specific blocker. Quercetin-induced membrane hyperpolarization was measured by fluorescence-activated cell sorting (FACS) with voltage sensitive dye, bis (1,3-dibutylbarbituric acid) trimethine oxonol ($DiBAC_4$2(3); 100 nM). Quercetin-evoked hyperpolarization was prevented by TEA. Quercetin produced an antiproliferative effect ($30.3{\pm}13.5%$) which was recovered to $53.3{\pm}10.5%$ and $72.9{\pm}3.7%$ by TEA and IBX, respectively. Taken together our results indicate that activation of $BK_{Ca}$ channels may be considered an important target related to the action of quercetin on human bladder cancer cells.

• The Korean Journal of Pharmacology
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• v.26 no.1
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• pp.55-66
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• 1990

In both resting and opsonized zymosan activated neutrophils, ATP stimulated superoxide generation, whereas adenosine inhibited it slightly. The superoxide generation in activated neutrophils to ATP was greater than that of resting neutrophils. In $Ca^{++}$ free medium, inhibitory effect of adenosine on superoxide generation was detectable, whereas ATP did not have any effect. The stimulatory effect of ATP on superoxide generation was inhibited by adenosine in a dose dependent manner. Neither ATP nor adenosine had any effect on NADPH oxidase acitivity. Effects of ATP or adenosine on superoxide generation were more prominent than that by other triphosphate nucleotides or nucleosides. ATP and ADP further stimulated $Ca^{++}$ uptake and increased cytosolic free $Ca^{++}$ level in neutrophils activated by opsonized zymosan, but adenosine inhibited a $Ca^{++}$ mobilization. Verapamil effectively and tetrodotoxin slightly inhibited an increase of cytosolic free $Ca^{++}$ level induced by ATP. Inhibitory effect of either verapamil or tetrodotoxin on superoxide generation in the ATP plus opsonized zymosan-activated neutrophils was greater than in the cells activated by opsonized zymosan alone. Tetraethylammonium chloride had no apparent effect on superoxide generation. CCCP, 2,4-dinitrophenol, diphenylhydantoin and procaine all inhibited superoxide generation in neutrophils activated by opsonized zymosan. Among these, CCCP only inhibited a stimulatory effect of ATP. ATP further stimulated a loss of sulfhydryl groups in activated neutrophils, whereas adenosine had no effect on it. These results suggest that functional responses of neutrophils may be regulated at least partly by purines. ATP and adenosine may further after functional responses of activated neutrophils through their effect on $Ca^{++}$ uptake, membrane phosphorylation and oxidation of soluble sulfhydryl groups.

• The Korean Journal of Physiology and Pharmacology
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• v.2 no.2
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• pp.133-145
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• 1998

$Ca^{2+}-signals$ in endothelial cells are determined by release from intracellular stores and entry through the plasma membrane. In this review, the nature of $Ca^{2+}$ entry and mechanisms of its control are reviewed. The following ion channels play a pivotal role in regulation of the driving force for $Ca^{2+}$ entry: an inwardly rectifying $K^+$ channel, identified as Kir2.1, a big-conductance, $Ca^{2+}-activated$ $K^+$ channel (hslo) and at least two $Cl^-$ channels (a volume regulated $Cl^-$ channel, VRAC, and a $Ca^{2+}$ activated $Cl^-$ channel, CaCC). At least two different types of $Ca^{2+}$-entry channels exist: 1. A typical CRAC-like, highly selective $Ca^{2+}$ channel is described. Current density for this $Ca^{2+}$ entry is approximately 0.1pA/pF at 0 mV and thus 10 times smaller than in Jurkat or mast cells. 2. Another entry pathway for $Ca^{2+}$ entry is a more non-selective channel, which might be regulated by intracellular $Ca^{2+}$. Although detected in endothelial cells, the functional role of trp1,3,4 as possible channel proteins is unclear. Expression of trp3 in macrovascular endothelial cells from bovine pulmonary artery induced non-selective cation channels which are probably not store operated or failed to induce any current. Several features as well as a characterisation of $Ca^{2+}$-oscillations in endothelial cells is also presented.

• Korean Journal of Materials Research
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• v.13 no.12
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• pp.785-790
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• 2003

We have synthesized some phosphors in the system $CaO-Y_2$$O_3$-$Al_2$$O_3$by combinatorial polymerized-complex method. Composition and synthetic temperature of phosphors in the library was screened from the emission intensities of individual samples under VUV excitation. In $Tb^{ 3＋}$-activated $CaO-Y_2$$O_3$-$Al_2$$O_3$, green phosphors showing good intensity were found to be X$O_3$$O_{7}$, CaYA1O$_4$, YA1O$_3$, $Y_3$$Al_{5}$$O_{12}$, $Y_4$$A1_2$$O_{9}$ .

• The Korean Journal of Physiology and Pharmacology
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• v.8 no.2
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• pp.69-76
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• 2004

A variety of G protein coupled receptors (GPCRs) are expressed in the presynaptic terminals of central and peripheral synapses and play regulatory roles in transmitter release. The patch-clamp whole-cell recording technique, applied to the calyx of Held presynaptic terminal in brainstem slices of rodents, has made it possible to directly examine intracellular mechanisms underlying the GPCR-mediated presynaptic inhibition. At the calyx of Held, bath-application of agonists for GPCRs such as $GABA_B$ receptors, group III metabotropic glutamate receptors (mGluRs), adenosine $A_1$ receptors, or adrenaline ${\alpha}2$ receptors, attenuate evoked transmitter release via inhibiting voltage-activated $Ca^{2+}$ currents without affecting voltage-activated $K^+$ currents or inwardly rectifying $K^+$ currents. Furthermore, inhibition of voltage-activated $Ca^{2+}$ currents fully explains the magnitude of GPCR-mediated presynaptic inhibition, indicating no essential involvement of exocytotic mechanisms in the downstream of $Ca^{2+}$ influx. Direct loadings of G protein ${\beta}{\gamma}$ subunit $(G{\beta}{\gamma})$ into the calyceal terminal mimic and occlude the inhibitory effect of a GPCR agonist on presynaptic $Ca^{2+}$ currents $(Ip_{Ca})$, suggesting that $G{\beta}{\gamma}$ mediates presynaptic inhibition by GPCRs. Among presynaptic GPCRs glutamate and adenosine autoreceptors play regulatory roles in transmitter release during early postnatal period when the release probability (p) is high, but these functions are lost concomitantly with a decrease in p during postnatal development.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.11
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• pp.1020-1024
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• 2006

Europium$(Eu^{2+}\;or\;Eu^{3+})$-activated calcium aluminium silicate phosphors were synthesized for the first time and the structures and luminescence characteristics of these phosphors were investigated. The phosphors in this study emitted blue, green, and even red light depending on the starting milterials and annealing conditions for synthesis. In addition, the structure was also changed when the different starting materials were used. When $CaCO_3$ was used as a starting material, tetragonal $Ca_2Al_2SiO_7$ was formed. However, pure green light was emitted when the annealing was conducted in reduced atmosphere and red one was emitted by annealing in air. In the case of $CaSiO_3$ as a starting material, triclinic $CaAl_2Si_2O_8$ was formed and only pure blue emission was observed. Moreover, this blue phosphor exhibited higher intensity than that of commercial YAG:Ce phosphor, which showed the possibility of application on the phosphor for new light source such as a UV-LED.

• The Journal of Korean Medicine
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• v.19 no.2
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• pp.450-467
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• 1998

To research the characteristics of ion currents induced by inhibitory and excitatory herbs of oriental medicine, we used nystatin-perforated patch clamp technique under voltage clamp condition in periaqueductal gray neuron dissociated from Sprauge-Dawley rat, 10-15 days old. The results are as follows. 1. Ion current induced by $10mg/m{\ell}$ of Bupleuri Radix was inhibited $59.50{\pm}4.29%$ by $10^{-4}M$ bicuculline(p>0.01) but inhibition of $10.75{\pm}4.77%$ by $10^{-4}M$ tubocurarine and $4.75{\pm}4.23%$ by $10^{-4}M$ verapamil had no statistical significance(p>0.05). So ion current induced by Bupleuri Radix revealed only GABA induced $Cl^-$ current, not acetylcholine and $Ca^{2+}$ current. 2. Ion current induced by $20mg/m{\ell}$ of Coptidis Rhizoma was inhibited $47.20{\pm}7.88%$ by $10^{-4}M$ bicuculline(p<0.01) but $3.20{\pm}2.33%$ inhibition by $10^{-4}M$ tubocurarine and $1.00{\pm}1.00%$ inhibition by $10^{-4}M$ verapamil had no significance(p>0.05). So ion current induced by Coptidis Rhizoma revealed only GABA induced $Cl^-$ current, not acetylcholine and $Ca^{2+}$ current. 3. Ion current induced by $20mg/m{\ell}$ of Ecliptae Herba was inhibited $55.00{\pm}4.92%$ by $10^{-4}M$ bicuculline (p<0.01), and also inhibited $15.00{\pm}4.26%$ by $10^{-4}M$ tubocurarine(p<0.05), but inhibition of $6.00{\pm}3.03%$ by $10^{-4}M$ verapamil had no significance(p>0.05). So ion current induced by Ecliptae Herba showed GABA activated $Cl^-$ current and acetylcholine activated cation current, not $Ca^{2+}$ current 4. Ion current induced by $5mg/m{\ell}$ of Liriopis Tuber was inhibited $15.20{\pm}4.57%$ by $10^{-4}M$ bicuculline<0.05) and also inhibited $14.00{\pm}3.00%$ by $10^{-4}M$ tubocurarine(p<0.05), but inhibition of $5.20{\pm}4.80%$ by $10^{-4}M$ verapamil had no significance(p>0.05). So ion current induced by Liriopis Tuber showed GABA. activated $Cl^-$ current and acetylcholine activated cation current, not $Ca^{2+}$ current. 5. Ion current induced by $5mg/m{\ell}$ of Aconiti Tuber was inhibited $97.00{\pm}1.34%$ by $10^{-4}M$ bicuculline(p<0.01), $80.00{\pm}9.83%$ by $10^{-4}M$ tubocurarine(p<0.01), and $24.00{\pm}6.18%$ by $10^{-4}M$ verapamil(p<0.05). So ion current induced by Aconiti Tuber revealed GABA activated $Cl^-$ current and acetylcholine activated cation current and $Ca^{2+}$ current. 6. Ion current induced by $10mg/m{\ell}$ of Zingiberis Rhizoma was inhibited $33.00{\pm}7.43%$ by $10^{-4}$ bicuculline(p<0.05), $10.20{\pm}1.83%$ by $10-^{-4}M$ tubocurarine(p<0.01), and $14.00{\pm}2.16%$ by $10^{-4}M$ verapamil(p<0.01) So ion current induced by Zingiberis Rhizoma revealed GABA activated $Cl^-$ current and acetylcholine activated cation outtent and $Ca^{2+}$ current. 7. Ion current induced by $10mg/m{\ell}$ of Boshniakiae Herba was inhibited $65.00{\pm}13.75%$ by $10^{-4}M$ bicuculline(p<0.05), $38.00{\pm}9.24%$ by $10^{-4}M$ tubocurarine(p<0.05), and $33.25{\pm}7.42%$ by $10^{-4}M$ verapamiHp<0.05). So ion current induced by Bpshniakiae Herba revealed GABA activated $Cl^-$ current and acetylcholine activated cation current and $Ca^{2+}$ current. These results suggest that a point of difference between inhibitory and excitatory herbs is existence of$Ca^{2+}$ current.

• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.4
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• pp.395-403
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• 2020

CaO-based by-product, which consist of CaO, SO3, Al2O3 and so on, has being used to raw materials of CaO compound. When It was applied to recycling water of remicon, concrete performance can be enhanced because hydration reaction of powder material is accelerated. In this study, activated-sludge, which was putted desulfurization gypsum of CaO-based in recycling water, was manufactured to verify effect of them, and then they was investigated by characteristics of redy-mixde concrete. As a result of concrete tests, it was confirmed that there is no problem of strength or drying shrinkage while ensuring workability. Therefore, the possibility of specific application using activated sludge was confirmed.

• Bulletin of Food Technology
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• v.18 no.2
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• pp.52-58
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• 2005

최근 20여년 동안 Panax ginseng의 다양한 효과가 연구 되어져 왔다. Panax ginseng의 주요 활성 성분인 ginsenosides는 오직 인삼에서만 발견되어지는 saponin이다. 최근 들어 신경, 非신경 또는 복합적으로 분포된 세포에서 ginsenoside가 $Ca^2+$, $K^+$,$Na^+$,$Cl^-$ channel이나 ligand gated ionchannel (5-HT3, nicotinic acetylcholine, NMDA receptor)과 같은 다양한 ion channel을 조절하는증거들이 발표되고 있다. Ginsenoside는 voltage-dependent $Ca^2+$, $K^+$,$Na^+$ channel의 활성을 억제하는 반면 $Ca^2+$-activated $Cl^-$ channel이나 $Ca^2+$-activated $K^+$ channel의 활성은 증가 시키는 것으로 나타났다. 또한 흥분성 ligand-gated ion channel인 $5-HT_3$, nicotinic acetylcholine, NMDA receptor의 활성은 억제한다. 본 총설에서는 현재까지 알려진 ion channel 활성에 대한 ginsenoside의 조절작용과 이것으로 인해 어떻게 생물학적 효능과 연결이 되어있는지에 대하여 이야기하고자 한다.