• The Korean Journal of Physiology and Pharmacology
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• v.15 no.6
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• pp.431-436
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• 2011

Vascular smooth muscle cells can obtain a proliferative function in environments such as atherosclerosis in vivo or primary culture in vitro. Proliferation of vascular smooth muscle cells is accompanied by changes in ryanodine receptors (RyRs). In several studies, the cytosolic $Ca^{2+}$ response to caffeine is decreased during smooth muscle cell culture. Although caffeine is commonly used to investigate RyR function because it is difficult to measure $Ca^{2+}$ release from the sarcoplasmic reticulum (SR) directly, caffeine has additional off-target effects, including blocking inositol trisphosphate receptors and store-operated $Ca^{2+}$ entry. Using freshly dissociated rat aortic smooth muscle cells (RASMCs) and cultured RASMCs, we sought to provide direct evidence for the operation of RyRs through the $Ca^{2+}$- induced $Ca^{2+}$ -release pathway by directly measuring $Ca^{2+}$ release from SR in permeabilized cells. An additional goal was to elucidate alterations of RyRs that occurred during culture. Perfusion of permeabilized, freshly dissociated RASMCs with $Ca^{2+}$ stimulated $Ca^{2+}$ release from the SR. Caffeine and ryanodine also induced $Ca^{2+}$ release from the SR in dissociated RASMCs. In contrast, ryanodine, caffeine and $Ca^{2+}$ failed to trigger $Ca^{2+}$ release in cultured RASMCs. These results are consistent with results obtained by immunocytochemistry, which showed that RyRs were expressed in dissociated RASMCs, but not in cultured RASMCs. This study is the first to demonstrate $Ca^{2+}$ release from the SR by cytosolic $Ca^{2+}$ elevation in vascular smooth muscle cells, and also supports previous studies on the alterations of RyRs in vascular smooth muscle cells associated with culture.

• The Journal of Internal Korean Medicine
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• v.12 no.2
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• pp.30-43
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• 1991

Mahwangsan is used in the treatment of asthma due to wind and cold(風寒喘). This study was carried out to investigate the effect of Mahwangsan extract and each drug composing it on the contractile force of the isolated guinea pig trachea muscle and elucidate its mechanism. The results were obtained as follows; 1. The isolated trachea smooth muscle of guinea pig was signifi-cantly relaxed by the administration of Mahwangsan extract. 2. The contractile response of the isolated trachea smooth muscle of guinea pig to histamine was significantly inhibited by the administration of Mahwangsan extract. 3. The contractile response of the isolated trachea smooth muscle of guinea pig to histamine was significantly inhibited by the administraction of Herba Ephedrae, Cortex Cinnamoni, Flos Farfarae, Fructus Chebulae and Semen Armeniacae extract. 4. The contractile response of the isolated trachea smooth muscle of guinea pig to acetylcholine was significantly inhibited by the administration of Mahwangsan extract. 5. The contractile response of the isolated trachea smooth muscle of guinea pig to acetylcholine was significantly inhibited by the administration of Herba Ephedrae, Flos Farfarae, Fructus Chebulae and Semen Armeniacae extract. 6. The contractile response of the isolated trachea smooth muscle of guinea pig to 5-hydroxytryptamine was significantly inhibited by the administration of Mahwangsan extract. 7. The contractile response of the isolated trachea smooth muscle of guinea pig to 5-hydroxytryptamine was significantly inhibited by the administration of Herba Ephedrae, Flos Farfarae, Fructus Chebulae and Semen Armeniacae extract.

• Tunnel and Underground Space
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• v.21 no.3
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• pp.235-243
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• 2011

In this study, a control blast method, which utilizes crack guide holes, is suggested to achieve smooth fracture plane and minimize blast damage zone (BDZ) in smooth blasting. In order to verify the effectiveness of crack guide holes on the fracture plane control in blasting, fracture process analyses which consider regular smooth blasting and guide hole smooth blasting had been conducted and the fracture planes resulting from the analyses had been compared. The analyses models considered the ignition of the blast holes using detonation cords and each guide hole placed between blast holes. From the results, the smooth blasting utilizing guide holes showed lower fracture plane roughness than regular smooth blasting method in the hole spacing range between 20 to 40cm.

• Biotechnology and Bioprocess Engineering:BBE
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• v.5 no.1
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• pp.40-43
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• 2000

Pyrrolidinedithiocarbamate (PDTC) and N-Acetylcysteine (NAC) are metal and nonmetal-chelating antioxidant which can induce rat and human smooth muscle cell death. When the smooth muscle cells from mouse aorta (MASMC) that we successfully cultured recently was exposed to PDTC and NAC in a normal serum state, the cells were induced to death by these compounds. However, PDTC did not induce the cell death in a serum depleted medium. This data suggests that certain factors in the serum may mediate the cytotoxic effect of PDTC. The metal chelator, Ca-EDTA blocked PDTC-induced cell death, but Cu-, Fe-, and Zn-EDTA did not block the PDTC-induced cell death. This data indicated that copper, iron, and zinc in the serum may lead to the cytotoxic effect of PDTC. Investigation of the intracellular zinc level in PDTC-induced smooth muscle cell death using the zinc probe dye N-(6-methoxy-8-quinolyl)-p-toluenesulfonamide shows that only the muscle-containing layers of the arteries have higher level of zinc. As expected, PDTC increased the intracellular fluorescence level of the zinc. In agreement with these results, the addition of an exogenous metal, zinc, induced the vascular aortic smooth muscle cell death which led to an increased intracellular zinc level. We concluded that PDTC induced mouse aortic smooth muscle cell death required not only zinc level but also intracellular copper and iron level. The mechanism of this antioxidant to induce vascular smooth muscle cell death may provide a new strategy to prevent their proliferation in arteriosclerotic lesions.

• Molecules and Cells
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• v.20 no.2
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• pp.263-270
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• 2005

Transactivation of EGF-receptor (EGFR) by G-protein coupled receptors (GPCRs) is emerging as an important pathway in cell proliferation, which plays a crucial role in the development of atherosclerotic lesion. Angiotensin II (Ang II) has been identified to have a major role in the formation of atherosclerotic lesions, although the underlying mechanisms remain largely unclear. We hypothesize that Ang II promotes the proliferation and migration of smooth muscle cells through the release of heparin-binding epidermal growth factor like growth factor (HB-EGF), transactivation of EGFR and activation of Akt and Erk 1/2, with matrix metalloproteases (MMPs) playing a dispensable role. Primary rat aortic smooth muscle cells were used in this study. Smooth muscle cells rendered quiescent by serum deprivation for 12 h were treated with Ang II (100 nM) in the presence of either GM6001 ($20{\mu}M$), a specific inhibitor of MMPs or AG1478 ($10{\mu}M$), an inhibitor of EGFR. The levels of phosphorylation of EGFR, Akt and Erk 1/2 were assessed in the cell lysates. Inhibition of MMPs by GM6001 significantly attenuated Ang II-stimulated phosphorylation of EGFR, suggesting that MMPs may be involved in the transactivation of EGFR by Ang II receptor. Furthermore Ang II-stimulated proliferation and migration of smooth muscle cells were significantly blunted by inhibiting MMPs and EGFR and applying HB-EGF neutralization antibody, indicating that MMPs, HB-EGF and EGFR activation is necessary for Ang-II stimulated migration and proliferation of smooth muscle cells. Our results suggest that inhibition of MMPs may represent one of the strategies to counter the mitogenic and motogenic effects of Ang II on smooth muscle cells and thereby prevent the formation and development of atherosclerotic lesions.

• BMB Reports
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• v.33 no.6
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• pp.531-536
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• 2000

Tropomyosin (TM) is an important actin binding protein involved in regulation of muscle contraction. Unacetylated striated tropomyosin failed to bind to actin whereas unacetylated smooth tropomyosin bound well to actin. It has been demonstrated that high actin affinity of unacetylated ${\alpha}-tropomyosin$ was ascribed to the carboxyl terminal amino acid residues. In order to define the role of the carboxyl terminal residues of tropomyosin molecule on actin binding, two mutant tropomyosins were constructed. TM11 is identical to the striated tropomyosin except that the carboxyl terminal last three amino acids was replaced with $^{282}NNM^{284}$ whereas in TM14 $^{276}HA^{277}$ was substituted with smooth specific $^{276}QT^{277}$. TM11 and TM14 were overproduced in Escherichia coli and analyzed for actin affinity. The apparent binding constants (Kapp) of unacetylated tropomyosins were $2.2{\times}10^6M^{-1}$ for sm9, $1.03{\times}10^6M^{-1}$ for TM14, $0.19{\times}10^6M^{-1}$ for TM11, $>0.1{\times}10^6M^{-1}$ for striated, respectively. This result indicated that higher actin affinity of the unacetylated smooth tropomyosin was primarily attributed to the presence of QT residues in the smooth sequence. In case of the Ala-Ser (AS) dipeptide extension of the amino terminus of tropomyosin, Kapp were $21.1{\times}10^6M^{-1}$ for AS-sm9, $8.0{\times}10^6M^{-1}$ for AS-11, $4.7{\times}10^6M^{-1}$ for AS-14, $3.8{\times}10^6M^{-1}$ for AS-striated. AS-TM11 showed considerably higher actin affinity than AS-TM14, implying that interaction of Ala-Ser of the amino terminus with the carboxyl terminal residues. Since Kapp of AS-TM11 was significantly lower than that of AS-sm9, the presence of QT might be required for restoration of high actin affinity of the smooth ${\alpha}-tropomyosin$. These results suggested that the carboxyl terminal amino acid residues Glutamine275-Threonine276 are important for actin affinity of the recombinant smooth ${\alpha}-tropomyosin$, particularly of unacetylated smooth ${\alpha}-tropomyosin$.

• The Korean Journal of Physiology and Pharmacology
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• v.5 no.1
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• pp.1-8
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• 2001

Hyperpolarization of arterial smooth muscle by acetylcholine is considered to be produced by the release of an unidentified chemical substance, an endothelium-derived hyperpolarizing factor (EDHF). Several chemicals have been proposed as the candidate for EDHF. However, none of them fulfil completely the nature and property of EDHF. Ultrastructural observation with electron microscope reveals that in some arteries, gap junctions are formed between endothelial and smooth muscle cells. In small arterioles, injection of gap junction permeable dyes into an endothelial cell results in a distribution of the dye to surrounding cells including smooth muscle cells. These observations allow the speculation that myoendothelial gap junctions may have a functional significance. Simultaneous measurement of the electrical responses in both endothelial and smooth muscle cells using the double patch clamp method demonstrates that these two cell types are indeed electrically coupled, indicating that they behave as a functional syncytium. The EDHF-induced hyperpolarization is produced by an activation of $Ca^{2+}-sensitive\;K^+-channels$ that are inhibited by charybdotoxin and apamin. Agonists that release EDHF increase $[Ca^{2+}]_i$ in endothelial cells but not in smooth muscle cells. Inhibition of gap junctions with chemical agents abolishes the agonist-induced hyperpolarization in smooth muscle cells but not in endothelial cells. All these observations can be explained if EDHF is an electrotonic signal propagating from endothelium to smooth muscle cells through gap junctions.

• Communications of the Korean Mathematical Society
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• v.18 no.3
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• pp.521-532
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• 2003

In this paper, we introduce the notions of ($T_{i},\;T_{j}$)-fuzzy (r, s)-preopen sets and fuzzy pairwise (r, s)-precontinuous mappings in smooth bitopological spaces and then we investigate some of their characteristic properties.

• Bulletin of the Korean Mathematical Society
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• v.57 no.2
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• pp.443-447
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• 2020

For n ≥ 2, we characterize the smooth points of the unit ball of 𝓛_s(ⁿ𝑙²_∞).

• Journal of the Chungcheong Mathematical Society
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• v.29 no.2
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• pp.367-374
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• 2016

In this paper, we introduce intuitionistic fuzzy pairwise semiopen and semiclosed mappings in intuitionistic smooth bitopological spaces, and obtain the characterizations for the mappings.