• 대한약리학회지
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• 제12권2호
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• pp.13-19
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• 1976

A fluid extract of Zizyphi Semen was employed in this experiment. The cardiac effects of Zizyphi Semen were examined on isolated rabbits atria and heart in situ of anesthetized cats and rabbits. The adrenergic blocking activity and refractory period of cardiac muscle were measured after administration of this drug. In rabbits and cats the antiarrhythmic action of Zizyphi Semen on atrial and ventricular arrhythmias produced by epinephrine or ouabain was examined. The results were following: 1. Zizyphi Semen produced a decrease in rate and contractile amplitude of the isolated rabbit atria and had a week blocking effect on epinephrine acceleration of atrial movement. 2. Zizyphi Semen effectively abolished the spontaneous arrhythmia occurring in the isolated rabbit atria ana the atrial arrhythmia induced by ouabain. 3. Zizyphi Semen produced a marked prolongation of the refractory period in isolated atrial muscle of rabbit. 4. Zizyphi Semen prevented the induction of ventricular arrhythmia arising from excessive dose of epinephrine in anesthetized rabbits and cats. 5. With regard to the ventricular arrhythmia induced by a continuous infusion of ouabain, Zizyphi Semen exerted suppressive effect and produced a marked prolongation of cardiac arrest time in anesthetized rabbits and cats. From the above results, it may be concluded that Zizyphi Semen is effective against atrial and ventricular arrhythmias. The antiarrhythmic effect of this drug may be the result of direct myocardial depressive and partially adrenergic beta receptor blocking activities including prolongation of the refractory period of cardiac muscle.

• The Korean Journal of Physiology and Pharmacology
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• 제3권4호
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• pp.375-382
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• 1999

Growing evidence indicates that enhanced generation or actions of nitric oxide (NO) are implicated in the pathogenesis of hypertension in spontaneously hypertensive rats and diabetic nephropathy in streptozotocin (STZ)-induced diabetic rats. We investigated whether inducible nitric oxide synthase (iNOS) expression in STZ-induced diabetic rats is responsible for the alterations of vascular reactivity. Diabetic state was confirmed 28 days after injection of STZ (i.p) in rats by measuring blood glucose. In order to evaluate whether short term (4 weeks) diabetic state is related with altered vascular reactivity caused by iNOS expression, isometric tension experiments were performed. In addition, plasma nitrite/nitrate (NOx) levels and expression of iNOS in the lung and aorta of control and STZ-treated rats were compared by using Griess reagent and Western analysis, respectively. Results indicated that STZ-treated rats increased the maximal contractile response of the aorta to phenylephrine (PE), and high $K^+,$ while the sensitivity remained unaltered. Endothelium-dependent relaxation, but not SNP-mediated relaxation, was reduced in STZ-treated rats. Plasma nitrite/nitrates are significantly increased in STZ-treated rats compared to controls. The malondialdehyde (MDA) contents of liver, serum, and aorta of diabetic rats were also significantly increased. Furthermore, nitrotyrosine, a specific foot print of peroxynitrite, was significantly increased in endothelial cells and smooth muscle layers in STZ-induced diabetic aorta. Taken together, the present findings indicate that enhanced release of NO by iNOS along with increased lipid peroxidation in diabetic conditions may be responsible, at least in part, for the augmented contractility, possibly through the modification of endothelial integrity or ecNOS activity of endothelium in STZ-diabetic rat aorta.

• Journal of Yeungnam Medical Science
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• 제5권2호
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• pp.111-119
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• 1988

효소와 기계적인 힘을 이용하여 얻어진 심장세포를 심근세포와 내피세포를 분리하여 48시간 배양한 후 양군으로 나눠서 관찰하였다. 실험군은 배양중에 10% DMSO에 1시간 처리하였고 DMSO를 처리하지 않고 계속 배양한 것을 대조군으로 하였다. DMSO효과를 관찰하기 위하여 도립현미경하에서 세포의 형태, 수축능력, 증식 능력등을 관찰하였고, 심근세포에서는 succinate dehydrogenase 반응으로 사립체의 증감을 대조군과 비교하였고, 심장내과세포에서는 thiamine pyrophosphatase의 반응으로 Golgi의 양을 대조군으로 비교하였다. 실험 결과를 요약하연 다음과 같다. 1. DMSO에 의하여 심근세포는 분화된 형태로 모양이 길어졌고 사립체의 증가에 의해 succinate dehydrogenase의 반응이 대조군보마 강하게 나타났다. 2. DMSO에 의해 심근세포는 근세섬유의 파괴와 혼란이 초래되었고 이로 인하여 수축능력이 감소되었다. 3. 심장내과 세포는 DMSO에 의해 세포증식이 감소되고 고유기능이 강조되어 Golgi의 표지효소안 thiamine pyrophosphatase의 반응이 대조군보다 강하였다. 4. 심장내과세포는 DMSO의 세포접착력 소실과 운동성 소실작용에 의해 배양중 많은 세포의 손실이 초래되었다.

• Journal of Periodontal and Implant Science
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• 제26권4호
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• pp.1003-1012
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• 1996

The induction of a phenotype with preoperties may have clinical significance in the acceleration of the wound-healing process. Wound contraction involves a specialized cell known as the myofibroblast. The myofibroblasts can be identified by their intense staining of actin bundles with anti-actin antibody. Tissue-specific actin distribution is correlated with the contractile activity of the myofibroblasts and smooth muscle etc. This study was performed to determine the expression of actin filaments in the cytoplasm of cultured human gingival fibroblsts after GaAs laser(BIOSAER, Korea) irradiation. Human gingival fibroblasts were cultured from explants of normal interdental gingival tissue. The third-generation fibroblasts were used for immunohistochemical study. The cultured fibroblasts were exposed $0.53joule/cm^2$(lmW, 7 mimutes) of energy density, and then observed by immunohistochemical method using, rabbit anti0gelsolin, hen smooth muscle polyclonal antibody(Chemicon international inc.), and biotinylated goat anti-rabbit IgG(Vectastain) 24-, 36-, 48-hour after laser irradiation Following results were obtained ; 1. In nonirradiated cultures, round shaped active fibroblasts with abundant cytoplasm and prominet nucleoli were observed. 2. In 24- and 36-hour cultures after laser irradiation, spindle shaped cells with long process were observed. The intensity of stain was seen in cytoplasm of these modified fibroblasts. 3. In 48-hoour cultures after laser irradiation, stained spindle shape cell were not observed. The results suggest that the effect of the galium-arsenide laser treatment on cultured gingival fibroblasts is the rapid development of cytoplasmic actin filaments.

• The Korean Journal of Physiology and Pharmacology
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• 제22권4호
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• pp.437-445
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• 2018

${\alpha}$-Iso-cubebene (ICB) is a dibenzocyclooctadiene lignin contained in Schisandra chinensis (SC), a well-known medicinal herb that ameliorates cardiovascular symptoms, but the mechanism responsible for this activity has not been determined. To determine the role played by ICB on the regulation of vascular tone, we investigated the inhibitory effects of ICB on vascular contractile responses by adrenergic ${\alpha}$-receptor agonists. In addition, we investigated the role on myosin light chain (MLC) phosphorylation and cytosolic calcium concentration in vascular smooth muscle cells (VSMC). In aortic rings isolated from C57BL/6J mice, ICB significantly attenuated the contraction induced by phenylephrine (PE) and norepinephrine (NE), whereas ICB had no effects on KCl (60 mM)-induced contraction. In vasculatures precontracted with PE, ICB caused marked relaxation of aortic rings with or without endothelium, suggesting a direct effect on VSMC. In cultured rat VSMC, PE or NE increased MLC phosphorylation and increased cytosolic calcium levels. Both of these effects were significantly suppressed by ICB. In conclusion, our results showed that ICB regulated vascular tone by inhibiting MLC phosphorylation and calcium flux into VSMC, and suggest that ICB has anti-hypertensive properties and therapeutic potential for cardiovascular disorders related to vascular hypertension.

• 한국축산식품학회지
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• 제36권6호
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• pp.819-828
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• 2016

Muscle fiber characteristics account for meat quality and muscle fibers are mainly classified into three or more types according to their contractile and metabolic properties. However, the majority of previous studies on bovine skeletal muscle are based on myosin ATPase activity. In the present study, the differences in the characteristics of muscle fibers classified by the expression of myosin heavy chain (MHC) among four bovine skeletal muscles such as longissimus thoracis (LT), psoas major (PM), semimembranosus (SM) and semi-tendinosus (ST) and their relationships to beef quality were investigated. MHCs 2x, 2a and slow were identified by LC-MS/MS and IIX, IIA and I fiber types were classified. PM, which had the smallest size and highest density of fibers regardless of type, showed the highest myoglobin content, CIE $L^*$, $a^*$, $b^*$ and sarcomere length (p<0.05), whereas ST with the highest composition of IIX, showed high shear force and low sarcomere length (p<0.05). The correlation coefficients between muscle fiber characteristics and meat quality showed that type IIX is closely related to poor beef quality and that a high density of small-sized fibers is related to redness and tenderness. Therefore, the differences in meat quality between muscles can be explained by the differences in muscle fiber characteristics, and especially, the muscles with good quality are composed of more small-sized fibers regardless of fiber type.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제18권1호
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• pp.115-119
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• 1996

Myoepithelioma is composed exclusively of myoepithelial cells. Myoepithelial cells are ectodermally derived contractile cells that can be routinely identified in many normal tissues having secretory function such as major and minor salivary glands, lacrimal gland and sweat gland. Tumors composed exclusively of myoepithelial cells, so-called myoepitheliomas, are rare-less than 1% of all salivary gland tumors. Grossly, these tumors are well demarcated. The external surface is smooth and may be bosselated. The cut surface is white and homogenous. Microscopically, these tumors are surrounded by a thin fibrous capsule. They are composed of benign-appearing spindle- shaped and/or polygonal cells. Mitoses are rare. Frequently these tumors contain myxomatous stroma which is susceptible to alcial blue stain. Clinically, myoepitheliomas present as slow-glowing, painless masses and can not distinguished from pleomorphic adenomas. Treatment is the same as for pleomorphic adenoma, and the surgical excision should include a margin of normal tissue. Although the majority of myoepitheliomas have behaved in a beingn manner, pleomorphism and mitotic activity have been associated with local aggressiveness.

• The Korean Journal of Physiology
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• 제20권1호
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• pp.125-133
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• 1986

Ethanol이 고양이 회장 종주근의 수축에 미치는 영향을 관찰한 결과 정상 Tyrode용액에서는 $0.5{\pm}4%$ 범위내에서 자발적 수축 및 기초장력을 억제하였으나 $Na^+$이 surcose로 대치된 용액에서는 수축을 유발시켰다. 이러한 수축은 ethanol의 농도에 비례하여 증가하였으며 용액내의 Na-free 용액으로 처리한 기간이 길수록 증가하였다. 용액내 $Ca^{2+}$이 없는 경우에도 ethanol에 의한 수축은 $La{+3}$에 의해 억제되었으나 verapamil을 전처치한 후 Na-free액을 처리했을 때는 수축이 나타나지를 않았다. Ethanol은 $^45Ca$의 유출에는 어떤 영향을 나타내지는 못하였다. 이상의 결과로 보아 Na-free용액에서 ethanol은 세포막에 결합하고 있는 $Ca^{2+}$이나 세포내부에 결합하고 있는 $Ca^{2+}$의 세포내로 유리를 증가시켜 수축을 유발시키는 것으로 사료된다.

• The Korean Journal of Physiology and Pharmacology
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• 제15권5호
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• pp.267-272
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• 2011

A number of studies have demonstrated that 5-hydroxytryptamine (5-HT) can induce muscle contraction or relaxation response and enhance secretion in the gastrointestinal tract via a multiplicity of 5-HT receptor subtypes. In the present study, we investigated the pharmacological characterization of the 5-HT-induced contractile response in longitudinal smooth muscle isolated from the feline ileum. Addition of 5-HT into muscle chambers enhanced the basal tone and spontaneous activity in a concentration-dependent manner. The neurotoxin tetrodotoxin did not alter the 5-HT-induced contraction of the longitudinal muscles. Neither atropine nor guanethidine affected the contraction. The 5-HT agonists, 5-methylserotonin hydrochloride and mosapride, also evoked concentration-dependent contractions. The 5-HT-induced contraction was enhanced by the $5HT_2$ receptor antagonist ketanserin and the $5-HT_3$ receptor antagonist ondansetron but was inhibited by the 5-$HT_1$ receptor antagonist methysergide and 5-$HT_4$ receptor antagonist GR113808. These results indicate that 5-$HT_1$ and 5-$HT_4$ receptors may mediate the contraction of the 5-HT-induced response and 5-$HT_2$ and 5-$HT_3$ receptors may mediate 5-HT-induced relaxation in feline ileal longitudinal smooth muscles.

• The Korean Journal of Physiology and Pharmacology
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• 제12권5호
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• pp.267-274
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• 2008

Since first discovered in chick skeletal muscles, stretch-activated channels (SACs) have been proposed as a probable mechano-transducer of the mechanical stimulus at the cellular level. Channel properties have been studied in both the single-channel and the whole-cell level. There is growing evidence to indicate that major stretch-induced changes in electrical activity are mediated by activation of these channels. We aimed to investigate the mechanism of stretch-induced automaticity by exploiting a recent mathematical model of rat atrial myocytes which had been established to reproduce cellular activities such as the action potential, $Ca^{2+}$ transients, and contractile force. The incorporation of SACs into the mathematical model, based on experimental results, successfully reproduced the repetitive firing of spontaneous action potentials by stretch. The induced automaticity was composed of two phases. The early phase was driven by increased background conductance of voltage-gated $Na^+$ channel, whereas the later phase was driven by the reverse-mode operation of $Na^+/Ca^{2+}$ exchange current secondary to the accumulation of $Na^+$ and $Ca^{2+}$ through SACs. These results of simulation successfully demonstrate how the SACs can induce automaticity in a single atrial myocyte which may act as a focus to initiate and maintain atrial fibrillation in concert with other arrhythmogenic changes in the heart.