• The Korean Journal of Physiology
• /
• v.18 no.2
• /
• pp.125-137
• /
• 1984

The effects of external $Ca^{2+}$ ana the inhibition of Na-pump on vanadate-induced contraction in isolated human and rat uterine smooth muscle were studied and the following results were observed. 1) Vanadate induced contraction in rat uterine muscle and showed maximal contraction at concentration of $5{\times}10^{-4}$M, and the contractile response to vanadate was more sensitive in human than rat uterine muscle. 2) Vanadate-induced contraction was not completely inhibited by $Ca^{2+}$ removal from PSS and the response to $Ca^{2+}$ removal was more sensitive in human than rat uterine muscle. 3) Vanadate-induced contraction decreased with increasing concentration of verapamil, but even in the presence of $3{\times}10^{-5}M$ verapamil which inhibited 100 K-induced contraction completely. about 40% of maximal contraction remained, and its amplitude was similar to that of contraction in $Ca^{2+}$-free solution. 4) Vanadate-induced contraction was increased by the inhibition of Na-pump and this increase also could be observed in the presence of $3{\times}10^{-5}M$ verapamil. 5) After pretreatment with $Ca^{2+}$-free PSS containing ouabain Vanadate-induced contraction was not increased, but the contractile response of these tissues to the addition of external $Ca^{2+}$ was remarkably increased in the presence of vanadate. 6) $3{\times}10^{-5}$M verapamil inhibited vanadate-induced $Ca^{45}$ influx completely, but after pretreatment with ouabain vanadate could induce remarkable $Ca^{45}$ influx even in the presence of verapmil. 7) With increasing the time of pretreatment with ouabain or $K^+$-free solution, the degree of increase in contraction by vanadate was more remarkable. 8) $10^{-4}M$ papaverine stowed a considerable inhibition of the increase in the vanadate-induced contraction by pretreatment with ouabain. 9) Acetylcholine-induced contraction increased with lengthening the duration of Na-pump inhibition even in the presence of verapamil. Considering above results it seems that the uterine muscle of human is more sensitive to vanadate than that of rat, and both internal and external $Ca^{2+}$ is utilized in vanadate·induced contraction. In the case of Na-pump inhibition several smooth muscle contracting agents seems to induce $Ca^{2+}$ influx which is not inhibited by verapamil. This $Ca^{2+}$ influx seems to be inhibited by papaverine and to be associated with membrane potential, although its precise characteristics is not certain.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.2 no.2
• /
• pp.20-32
• /
• 1992

$Na_2O-CaO-MgO-Al_2O_3-SiO_2$ glass was taken as a basic glass and then $Li_2O$ O.5wt%, $K_2O$ 2.0wt% were substituted to $Na_2O$content, MgO 12.0wt %, ZnO 6.0wt % to CaO content. And also nucleation agent $ZrO_2 and $CaF_2$ were added to 1-2wt% respectively. The crystal according to the compositions appeared wollastonite, diopside and diopside.tremolite. The glasses substituted NazO by LizO was decreased thermal expansion coeffcient but substituted by ZnO was opposite direction and both of them increased bending strength. In the ratio of ZrOz to CaF, each 1: 1 and 1: 2 have shown considerable crystal growth at $1000^{circ}C~1050^{\circ}C$ and high bending strength, but the glass in the ratio 1: 2 have shown lowest thermal expansion coefficient. The activation energy was at the glass in the ratio of ZrO, to CaFz 1:2 evaluated 55.24kvsl/mol by Ozawa type and 53.05kal/mol by kissinger type.

• The Korean Journal of Physiology and Pharmacology
• /
• v.5 no.6
• /
• pp.487-494
• /
• 2001

During depolarization, extrusion of $Ca^{2+}$ from sarcoplasmic reticulum through forward-mode $Na^+-Ca^{2+}$ exchange was studied in the rat ventricular myocytes patch-clamped in whole-cell configuration. In order to confine the $Ca^{2+}$ responses in a micro-domain by limiting the $Ca^{2+}$ diffusion time, rat ventricular myocytes were dialyzed with high (14 mM) EGTA. $K^+$ current was suppressed by substituting KCl with 105 mM CsCl and 20 mM TEA in the pipette filling solution and by omitting KCl in the external Tyrode solution. $Cl^-$ current was suppressed by adding 0.1 mM DIDS in the external Tyrode solution. During stimulation roughly mimicking action potential, the initial outward current was converted into inward current, $47{\pm}1%$ of which was suppressed by 0.1 mM $CdCl_2.$ 10 mM caffeine increased the remaining inward current after $CdCl_2$ in a cAMP-dependent manner. This caffeine-induced inward current was blocked by $1\;{\mu}M$ ryanodine, $10\;{\mu}M$ thapsigargin, 5 mM $NiCl_2,$ or by $Na^+\;and\;Ca^{2+}$ omission, but not by $0.1\;{\mu}M$ isoproterenol. The $I{\sim}V$ relationship of the caffeine-induced current elicited inward current from -45 mV to +3 mV with the peak at -25 mV. Taken together, it is concluded that, during activation of the rat ventricular myocyte, forward-mode $Na^+-Ca^{2+}$ exchange extrudes a fraction of $Ca^{2+}$ released from sarcoplasmic reticulum mainly by voltage-sensitive release mechanism in a micro-domain in the t-tubule, which is functionally separable from global $Ca^{2+}{_i}$ by EGTA.

• Proceeding of EDISON Challenge
• /
• 2017.03a
• /
• pp.703-707
• /
• 2017

배아줄기세포 유래 심근세포는 심근경색 등으로 심장이 제 기능을 다 하지 못할 때 치료적 목적으로 주사하여 환자의 심기능을 정상화 시키는 데에 쓰인다. 배아줄기세포 유래 심근세포는 페이스메이커 활동을 보이면서 막전압 고정상태에서도 주기적인 일과성 내향전류를 보이는 특징을 갖고 있다. 본 연구는 기존에 발표된 배아줄기세포 유래 심근세포의 시뮬레이션 모델을 이용하여 어떻게 하여 페이스메이커 활동이 나타나는지 그 기전을 밝히고자 하였다. 세포내 모든 이온을 고정하였을 때 모델 세포는 여전히 페이스메이커 활동을 보였다. 근장그물내 칼슘 이온을 고정하였을 때도 모델 세포는 페이스메이커 활동을 보였다. 그러나 Na-Ca 교환 전류를 차단하였을 때는 모델 세포의 페이스메이커 활동이 사라졌는데, 여기서 L-type $Ca^{2+}$ 전류의 칼슘 의존성 비활성화 기전을 제거하자 페이스메이커 활동이 지속되었다. 또한 Na-Ca 교환전류와 L-type $Ca^{2+}$ 전류만으로는 페이스메이커 활동이 보이지 않았으나 L-type $Ca^{2+}$ 전류의 크기를 3배로 증가시키자 페이스메이커 활동이 다시 나타남을 확인하였다. 따라서, 배아줄기세포 유래 심근세포의 페이스메이커 활동은 Na-Ca 교환전류와 L-type $Ca^{2+}$ 전류의 역할이 매우 중요하며, Na-Ca 교환전류는 L-type $Ca^{2+}$ 전류가 비활성화되지 않도록 칼슘 이온의 농도를 조절하는 데에 큰 역할을 하는 것으로 결론을 내렸다.

• Proceeding of EDISON Challenge
• /
• 2017.03a
• /
• pp.698-702
• /
• 2017

배아줄기세포 유래 심근세포는 심근경색 등으로 심장이 제 기능을 다 하지 못할 때 치료적 목적으로 주사하여 환자의 심기능을 정상화 시키는 데에 쓰인다. 배아줄기세포 유래 심근세포는 페이스메이커 활동을 보이면서 막전압 고정상태에서도 주기적인 일과성 내향전류를 보이는 특징을 갖고 있다. 본 연구는 기존에 발표된 배아줄기세포 유래 심근세포의 시뮬레이션 모델을 이용하여 어떻게 하여 페이스메이커 활동이 나타나는지 그 기전을 밝히고자 하였다. 세포내 모든 이온을 고정하였을 때 모델 세포는 여전히 페이스메이커 활동을 보였다. 근장그물내 칼슘 이온을 고정하였을 때도 모델 세포는 페이스메이커 활동을 보였다. 그러나 Na-Ca 교환 전류를 차단하였을 때는 모델 세포의 페이스메이커 활동이 사라졌는데, 여기서 L-type $Ca^{2+}$ 전류의 칼슘 의존성 비활성화 기전을 제거하자 페이스메이커 활동이 지속되었다. 또한 Na-Ca 교환전류와 L-type $Ca^{2+}$ 전류만으로는 페이스메이커 활동이 보이지 않았으나 L-type $Ca^{2+}$ 전류의 크기를 3배로 증가시키자 페이스메이커 활동이 다시 나타남을 확인하였다. 따라서, 배아줄기세포 유래 심근세포의 페이스메이커 활동은 Na-Ca 교환전류와 L-type $Ca^{2+}$ 전류의 역할이 매우 중요하며, Na-Ca 교환전류는 L-type $Ca^{2+}$ 전류가 비활성화되지 않도록 칼슘 이온의 농도를 조절하는 데에 큰 역할을 하는 것으로 결론을 내렸다.

• Proceedings of the Korean Society of Applied Pharmacology
• /
• 1994.04a
• /
• pp.289-289
• /
• 1994

흰쥐 적출 대동맥을 이용하여 혈관근의 $Na^{+}$/$Ca^{2+}$ 교환계의 기능과 성질을 구명코자 $Na^{+}$/$Ca^{2+}$ 교환계를 통한 수축 반응을 관찰하고 이때의 조직내 $Ca^{2+}$ 농도, cGMP 농도 및 이 수축에 대한 차단제와 저산소 처리의 영향을 조사하였다. 흰쥐 적출 대동맥은 $Na^{+}$ free 영양액하에서 수축반응을 일으켰고 이 수축 반응 ($Na^{+}$ free 수축반응)은 KCl 농도 증가에 비례하여 증가하였다. KCI 21.6mM 하의 $Na^{+}$ free유발 수축반응은 amiloride전처리하에서 용량-의존성으로 억제되었고 특히 tonic 수축반응이 예민하게 소실되었으며, benzamil과 verapamil 전처리하에서도 유의하게 억제되었다.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2008.11a
• /
• pp.525-528
• /
• 2008

This study is performed to know influence on the hydration according to alkali activator and method of pulverization and fineness in slag-cement. The compressive strength of mortar were examined when the SG powder of which the specific surface area are 4,000, 6,000, and 8000cm$^2$/g were substituted for 50wt.% of ordinary portland cement. Na$_2$SO$_4$, Ca(OH)$_2$, NaOH were used as alkali activator. respectively, As the results, the compressive strength of mortar increased as following the order, Na$_2$SO$_4$>Ca(OH)$_2$>None>NaOH until 7days. But at 28days, mortar used Ca(OH)$_2$ as alkali activator were the highest strength.

• The Korean Journal of Physiology and Pharmacology
• /
• v.4 no.5
• /
• pp.417-425
• /
• 2000

The underlying mechanism commonly applicable for both the positive and negative force-frequency relationships (FFR) was pursued in left atria (LA) of rat and rabbit. The species differences in the roles of $Na^+/Ca^{2+}$ exchanger and sarcoplasmic reticulum (SR), which are major intracellular $Ca^{2+}$ regulatory mechanisms in the heart, were examined in the amplitude accommodation to the frequency that changed from 3 Hz to the variable test frequencies for 5 minutes in the electrically field stimulated left atria (LA) of rat and rabbit. Norepinephrine strongly increased the frequency-related amplitude accommodation in both of rat and rabbit LA, while monensin, oubain or the reduced $Na^+$ and 0 mM $Ca^{2+}$ containing Tyrode solution increased the frequency-related amplitude accommodation only in the rabbit LA. Monenisn was also able to increase the frequency-related amplitude accommodation only in 1-day old rat LA but not in 4-week old rat LA that had 75% less $Na^+/Ca^{2+}$ exchanger with 97% higher SR than 1-day old rat LA. Taken together, it is concluded that the differences in the prevalence between myocardial $Na^+/Ca^{2+}$ exchanger and SR in the amplitude accommodation to the frequency-change determine the difference in the FFR between rat and rabbit heart.

• Geomechanics and Engineering
• /
• v.25 no.3
• /
• pp.245-251
• /
• 2021

The present study investigated the ageing effect on compressibility, permeability and shear strength behavior of kaolin and bentonite samples in the presence of NaCl and CaCl₂ solutions. The compressibility, permeability and shear strength parameters were determined on the 60, 190, and 250 days cured samples. The results have shown that, the kaolin sample becomes more compressible in the presence Ca²⁺ ions with ageing. Generally, the normalized compression index values of bentonite samples increased at the end of 60 days and 250 days curing time periods. The normalized permeability value of kaolin decreased by ageing in the presence of Na⁺ ions almost twofold. The permeability values of bentonite increased both in NaCl and CaCl₂ solutions during ageing. In the presence of Na⁺ ions kaolin had higher max. shear stress value than Ca²⁺ ions. When the max. shear stress values of 0, 60 and 190 days samples were compared, it was seen that NaCl solution had no significant effect on the shear strength of kaolin sample. However, the shear strength of kaolin increased in the CaCl₂ solution during ageing. In the presence of Ca²⁺ ions the max. shear stress value of bentonite was higher. The results of this study have shown that ageing has significant effects on the compressibility, permeability and shear strength of kaolinitic and bentonitic clayey soils.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.33 no.5
• /
• pp.187-190
• /
• 2023

In this study, antibacterial glasses were developed by the addition of CaO in ZnO-Na₂O-B₂O₃-SiO₂ glass system. The effect of the addition of CaO on the thermal properties, dissolution properties, surface zeta potential and antibacterial activity were analyzed. Differential thermal analysis (DTA) analysis was performed to analyze the thermophysical properties of 30ZnO-xCaO-20Na₂O-30B₂O₃-(20-x)SiO₂ (x = 0, 2, 4, 6, 8, 10 mol%). It was confirmed that the glass transition temperature decreased as the CaO content increased. The amount of released Zn²⁺ ions and surface zeta potential of glass samples increased with increasing CaO concentration. For these reasons, the antibacterial activity was dramatically improved. By the addition of CaO, we could successfully develop an antibacterial glass with 99.9 % antibacterial activity against both Escherichia coli and Staphylococcus aureus.