• International Journal of Oral Biology
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• 제40권1호
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• pp.11-17
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• 2015

The gingival epithelium of the oral cavity is constantly exposed to exogenous stimuli such as bacterial toxins, allergens, and thermal changes. These exogenous stimuli are resisted by innate host defense in gingival epithelial cells. However, it is unclear exactly how the exogenous stimuli affect detrimentally on the human gingival epithelial cells. Here, we investigated whether the allergen, such as house dust mite (HDM) extract, is linked to $Ca^{2+}$ signaling and proinflammatory cytokine expression in primary cultured human gingival epithelial cells. HDM extract induced an increase in intracellular $Ca^{2+}$ concentration ($[Ca^{2+}]_i$) in a dose-dependent manner. Extracellular $Ca^{2+}$ depletion did not affected on the HDM extract-induced increase in $[Ca^{2+}]_i$. The HDM extract-induced increase in $[Ca^{2+}]_i$ was abolished by the treatment with U73122 and 2-APB, which are inhibitors of phospholipase C (PLC) and inositol 1,4,5-trisphosphate ($IP_3$) receptor. Moreover, HDM extract induced the mRNA expression of pro-inflammatory cytokine, interleukin (IL)-8. These results suggest that HDM extract triggers $PLC/IP_3$-dependent $Ca^{2+}$ signaling and IL-8 mRNA expression in primary cultured human gingival epithelial cells.

• Animal cells and systems
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• 제3권1호
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• pp.53-58
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• 1999

The immunocytochemical method was used to identify the existence of voltage-dependent $Ca^{2＋}$-channels in mouse follicular oocytes. Three types of voltage-dependent $Ca^{2＋}$-channels were shown to exist in the follicular oocytes for the first time, the P/Q-type $Ca^{2＋}$-channel, the N-type $Ca^{2＋}$-channel, and the L-type $Ca^{2＋}$-channel. Among proven $Ca^{2＋}$-channels distributions of the P/Q-type $Ca^{2＋}$-channel and L-type $Ca^{2＋}$-channel showed localized staining (clustered pattern) on the oolemma. The distribution of the P/Q-type $Ca^{2＋}$-channel showed all localized staining, and the range of localized staining was from 1 to 8 in staining intensity. As the staining intensity increased from 1 to 8, the number of localized staining decreased. The L-type $Ca^{2＋}$-channel are homogeneously stained (29.4%-54.2%), while some of them (around 28.7%-44.1%) showed localized staining on the oolemma. However, the rest of them showed no staining at all (17.1%- 26.5%). On the contrary, the N-type $Ca^{2＋}$-channel showed mostly homogeneous staining, while nonstaining oocytes were around 33.8%. The rest showed localized staining (10%). However, staining intensity was much weaker than those of the P/Q-type and L-type $Ca^{2＋}$-channel. In fact, the N-type $Ca^{2＋}$-channel has been known to exist only in neurons (from ectoderm origin), but it is unknown how the N-type $Ca^{2＋}$-channel exists in the follicular oocytes (from mesoderm origin). Further studies are needed to examine the expression of $Ca^{2＋}$-channels during the developmental stages of the oocytes.

• 한국발생생물학회지:발생과생식
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• 제5권1호
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• pp.53-57
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• 2001

정자의 수정능력획득과 첨체반응은 Ca$^{2+}$에 의존적으로 일어나며, 수정능력획득 과정에서는 원형질막으로부터 cholesterol이 방출되어 첨체반응이 일어나기 쉬운 상태로 전환된다. 최근 세포막으로부터 cholesterol 방출을 촉진하는 methyl beta cyclodextrin (MBCD)이 첨체반응을 유발함이 알려졌으나 정자 주변의 Ca$^{2+}$ 농도와 관계없이 cholesterol 방출만으로 첨체반응이 유발되는지의 여부는 확인되지 않았다. 본 연구에서는 생쥐 정자에서 MBCD에 의한 첨체반응의 Ca$^{2+}$ 의존성을 조사하였다. 첨가된 Ca$^{2+}$이 없는 경우에도 MBCD는 농도 의존적으로 첨체반응을 증가시켰다. 저농도 (100 ${\mu}$M)의 Ca$^{2+}$의 존재시 MBCD에 의한 첨체반응이 유의하게 증가하였다. Ca$^{2+}$을 첨가하지 않은 배양액에 100 ${\mu}$M의 EGTA를 첨가한 경우 자발적 첨체반응을 유의하게 억제되었다. 같은 조건하에서 1 mM MBCD는 첨체반응을 유의하게 증가시켰으나 EGTA 비처리군보다 유의하게 낮아 MBCD에 의해 유발되는 첨체반응에 정자내부의 Ca$^{2+}$이 관여하는 것으로 사료된다. 이상의 결과에서 외부의 Ca$^{2+}$이 존재하지 않더라도 MBCD를 이용하여 첨체반응을 유발할 수 있으며 정자 내부의 Ca$^{2+}$이 원형질막 cholesterol의 방출에 따른 첨체반응 조절에 관여함을 알 수 있다.

• The Korean Journal of Physiology and Pharmacology
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• 제24권4호
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• pp.287-298
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• 2020

Ca²⁺ signaling of endothelial cells plays a critical role in controlling blood flow and pressure in small arteries and arterioles. As the impairment of endothelial function is closely associated with cardiovascular diseases (e.g., atherosclerosis, stroke, and hypertension), endothelial Ca²⁺ signaling mechanisms have received substantial attention. Increases in endothelial intracellular Ca²⁺ concentrations promote the synthesis and release of endothelial-derived hyperpolarizing factors (EDHFs, e.g., nitric oxide, prostacyclin, or K⁺ efflux) or directly result in endothelial-dependent hyperpolarization (EDH). These physiological alterations modulate vascular contractility and cause marked vasodilation in resistance arteries. Transient receptor potential (TRP) channels are nonselective cation channels that are present in the endothelium, vascular smooth muscle cells, or perivascular/sensory nerves. TRP channels are activated by diverse stimuli and are considered key biological apparatuses for the Ca²⁺ influx-dependent regulation of vasomotor reactivity in resistance arteries. Ca²⁺-permeable TRP channels, which are primarily found at spatially restricted microdomains in endothelial cells (e.g., myoendothelial projections), have a large unitary or binary conductance and contribute to EDHFs or EDH-induced vasodilation in concert with the activation of intermediate/small conductance Ca²⁺-sensitive K⁺ channels. It is likely that endothelial TRP channel dysfunction is related to the dysregulation of endothelial Ca²⁺ signaling and in turn gives rise to vascular-related diseases such as hypertension. Thus, investigations on the role of Ca²⁺ dynamics via TRP channels in endothelial cells are required to further comprehend how vascular tone or perfusion pressure are regulated in normal and pathophysiological conditions.

• 고려인삼학회:학술대회논문집
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• 고려인삼학회 1998년도 Advances in Ginseng Research - Proceedings of the 7th International Symposium on Ginseng -
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• pp.182-189
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• 1998

Administration of ginsenosides, a mixture of saponin extracted from Panax ginseng, decreased blood pressure in rat. Previous studies have shown that ginsenosides caused endothelium-dependent relaxation, which was associated with the formation of cyclic GMP, suggested that ginsenosides caused release of nitric oxide (NO) from the vascular endothelium. The aim of the present study was to characterize the endothelium-independent relaxation to ginsenosides in the isolated rat aorta. Ginsenosides caused a concentration-dependent relaxation of rat aortic rings without endothelium constricted with 25 mM KCI but affected only minimally those constricted with 60 mM KCI. Ginsenoside Rg3 (Rg3) was a more potent vasorelaxing agonist than total ginsenoside mixture and also the ginsenoside PPT and PPD groups. Relaxation to ginsenosides were markedly reduced by TEA, but not by glibenclamide. Rg3 significantly inhibited Cal'-induced concentration-contraction curves and the "50a2'influx in aortic rings incubated in 25 mM KCI whereas those responses were not affected in 60 mM KCI. Rg3 caused efflux of $"Rb in aortic rings that was inhibited by tetraethy- lammonium (TEA), an inhibitor of Ca"-dependent K'channels, but not by glibenclamide, an inhibitor of AfP-dependent K'channels. These findings indicate that ginsenosides may induce vasorelaxation via activation of Ca2'-dependent K'channels resulting in hyperpolarization of the vas- cular smooth muscle with subsequent inhibition of the opening of voltage-dependent Caf'channels. These effects could contribute to explain the red ginseng-associated vasodilation and the beneficial effect on the cardiovascular system.

• 대한물리치료과학회지
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• 제11권1호
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• pp.20-27
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• 2004

It is widely accepted that smooth muscle contraction is triggered by intracellular $Ca^{2+}$ ($[Ca^{2+}]_i$) released from intracellular $Ca^{2+}$ stores such as sarcoplasmic reticulum (SR) and from the extracellular space, The increased $[Ca^{2+}]_i$ can phosphorylate the 20-kDa myosin light chain ($MLC_{20}$) by activating MLC kinase (MLCK), and this initiates smooth muscle contraction. In addition to the $[Ca^{2+}]_i$-MLCK-tension pathway, a number of intracellular signal molecules, including mitogen-activated protein kinase (MAPK), protein kinase C (PKC), phosphatidylinositol 3-kinase (PI3K), and Rho-associated coiled coil-forming protein kinase (ROCK), play important roles in the regulation of smooth muscle contraction. However, the mechanisms regulating contraction of caldesmon (CaD), actin-binding protein, are not entirely elucidated in the presence of $Ca^{2+}$. It is known that CaD tightly interacts with actin and inhibits actomyosin ATPase activity. Therefore, the purpose of the present study was to investigate the roles of $Ca^{2+}$-dependent CaD in smooth muscle contraction. Endothelin-1 (ET-1), G-protein coupled receptor agonist and vasoconstrictor, increased both vascular smooth contraction and phosphorylation of CaD in the presence of $Ca^{2+}$. These results suggest that ET-1 induces contraction and phosphorylation of CaD in rat aortic smooth muscle, which may he mediated by the increase of $[Ca^{2+}]_i$.

• 환경생물
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• 제21권3호
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• pp.303-307
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• 2003

Tributyltin (TBT) used world-wide in antifouling paints toy ships is a wide-spread environmental pollutant. At low doses, antiproliferative modes of action have been shown to be involved, whereas at higher doses apoptosis seems to be the mechanism of toxicity in reproductive organs by TBT. In this study, we investigated that the mechanisms underlying apoptosis induced by TBT in R2C cell. Effects of TBT on intracellular $Ca^{2+}$ level and reactive oxygen species (ROS) were investigated in R2C cells by fluorescence detector. TBT significantly induced intracellular $Ca^{2+}$ level in a time-dependent manner. The rise in intracellular $Ca^{2+}$ level was followed by a time-dependent generation of reactive oxygen species (ROS) at the cytosol level. Simultaneously, TBT induced the release of cytochrome c from the mitochondrial membrane into the cytosol. Furthermore, ROS production and the release of cytochrome c were reduced by BAPTA, an intracellular $Ca^{2+}$ chelator, indicating the important role of $Ca^{2+}$ in R2C during these early intracellular events. In addition, Z-DEVD FMB, a caspase -3 inhibitor, decreased apoptosis by TBT. Taken together, the present results indicated that the apoptotic pathway by TBT might start with an increase in intracellular $Ca^{2+}$ level, continues with release of ROS and cytochrome c from mitochondria, activation of caspases, and finally results in DNA fragmentation.

• The Korean Journal of Physiology and Pharmacology
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• 제21권2호
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• pp.259-265
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• 2017

Excessive influx and the subsequent rapid cytosolic elevation of $Ca^{2+}$ in neurons is the major cause to induce hyperexcitability and irreversible cell damage although it is an essential ion for cellular signalings. Therefore, most neurons exhibit several cellular mechanisms to homeostatically regulate cytosolic $Ca^{2+}$ level in normal as well as pathological conditions. Delayed rectifier $K^+$ channels ($I_{DR}$ channels) play a role to suppress membrane excitability by inducing $K^+$ outflow in various conditions, indicating their potential role in preventing pathogenic conditions and cell damage under $Ca^{2+}$-mediated excitotoxic conditions. In the present study, we electrophysiologically evaluated the response of $I_{DR}$ channels to hyperexcitable conditions induced by high $Ca^{2+}$ pretreatment (3.6 mM, for 24 hours) in cultured hippocampal neurons. In results, high $Ca^{2+}$-treatment significantly increased the amplitude of $I_{DR}$ without changes of gating kinetics. Nimodipine but not APV blocked $Ca^{2+}$-induced $I_{DR}$ enhancement, confirming that the change of $I_{DR}$ might be targeted by $Ca^{2+}$ influx through voltage-dependent $Ca^{2+}$ channels (VDCCs) rather than NMDA receptors (NMDARs). The VDCC-mediated $I_{DR}$ enhancement was not affected by either $Ca^{2+}$-induced $Ca^{2+}$ release (CICR) or small conductance $Ca^{2+}$-activated $K^+$ channels (SK channels). Furthermore, PP2 but not H89 completely abolished $I_{DR}$ enhancement under high $Ca^{2+}$ condition, indicating that the activation of Src family tyrosine kinases (SFKs) is required for $Ca^{2+}$-mediated $I_{DR}$ enhancement. Thus, SFKs may be sensitive to excessive $Ca^{2+}$ influx through VDCCs and enhance $I_{DR}$ to activate a neuroprotective mechanism against $Ca^{2+}$-mediated hyperexcitability in neurons.

• The Korean Journal of Physiology and Pharmacology
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• 제21권2호
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• pp.241-249
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• 2017

Plasma membrane hyperpolarization associated with activation of $Ca^{2+}$-activated $K^+$ channels plays an important role in sperm capacitation during fertilization. Although Slo3 (slowpoke homologue 3), together with the auxiliary ${\gamma}^2$-subunit, LRRC52 (leucine-rich-repeat-containing 52), is known to mediate the pH-sensitive, sperm-specific $K^+$ current KSper in mice, the molecular identity of this channel in human sperm remains controversial. In this study, we tested the classical $BK_{Ca}$ activators, NS1619 and LDD175, on human Slo3, heterologously expressed in HEK293 cells together with its functional interacting ${\gamma}^2$ subunit, hLRRC52. As previously reported, Slo3 $K^+$ current was unaffected by iberiotoxin or 4-aminopyridine, but was inhibited by ~50% by 20 mM TEA. Extracellular alkalinization potentiated hSlo3 $K^+$ current, and internal alkalinization and $Ca^{2+}$ elevation induced a leftward shift its activation voltage. NS1619, which acts intracellularly to modulate hSlo1 gating, attenuated hSlo3 $K^+$ currents, whereas LDD175 increased this current and induced membrane potential hyperpolarization. LDD175-induced potentiation was not associated with a change in the half-activation voltage at different intracellular pHs (pH 7.3 and pH 8.0) in the absence of intracellular $Ca^{2+}$. In contrast, elevation of intracellular $Ca^{2+}$ dramatically enhanced the LDD175-induced leftward shift in the half-activation potential of hSlo3. Therefore, the mechanism of action does not involve pH-dependent modulation of hSlo3 gating; instead, LDD175 may modulate $Ca^{2+}$-dependent activation of hSlo3. Thus, LDD175 potentially activates native KSper and may induce membrane hyperpolarization-associated hyperactivation in human sperm.

• Clinical and Experimental Reproductive Medicine
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• 제28권1호
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• pp.13-24
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• 2001

Objective: In muscle and neuronal cells, calcium channels have been classified by electrophysiological and pharmacological properties into (1) voltage-dependent $Ca^{2+}$-channel (1) P/Q-type $Ca^{2+}$-channel (2) N-type $Ca^{2+}$-channel (3) L-type $Ca^{2+}$-channel (4) T-type $Ca^{2+}$-channel (5) R-type $Ca^{2+}$-channel. The present study was done in order to investigate whether there is any difference in $Ca^{2+}$-channel distribution between activated and normally fertilized embryos. Methods: The immunocytochemical method was used to identify the existence of voltage-dependent $Ca^{2+}$-channels in parthenogenetically activated 2-cell embryos by ethanol and $SrCl_2$ treatment. These 2-cell embryos were obtained by exposure to 6% ethanol for 6 min and to 10 mM $SrCl_2$ for 2h. Results: P/Q-type $Ca^{2+}$-channels and L-type $Ca^{2+}$-channels have been identified. Whereas, three type of $Ca^{2+}$-channel P/Q-type, N-type, L-type have been identified in 2-cell embryos fertilized in vivo. Conclusion: Activation by ethanol was faster than those by $SrCl_2$. However, there was difference in DAB staining of the embryos between ethanol and $SrCl_2$ treatment (87.7% and 54.1 %). Intensity of staining was also different between ethanol- and $SrCl_2$-treated group. However, it has not been known why there was some difference in DAB staining and staining intensity in the present study.