• BMB Reports
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• v.54 no.9
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• pp.464-469
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• 2021

Cardiomyocyte differentiation occurs through complex and finely regulated processes including cardiac lineage commitment and maturation from pluripotent stem cells (PSCs). To gain some insight into the genome-wide characteristics of cardiac lineage commitment, we performed transcriptome analysis on both mouse embryonic stem cells (mESCs) and human induced PSCs (hiPSCs) at specific stages of cardiomyocyte differentiation. Specifically, the gene expression profiles and the protein-protein interaction networks of the mESC-derived platelet-derived growth factor receptor-alpha (PDGFRα)⁺ cardiac lineage-committed cells (CLCs) and hiPSC-derived kinase insert domain receptor (KDR)⁺ and PDGFRα⁺ cardiac progenitor cells (CPCs) at cardiac lineage commitment were compared with those of mesodermal cells and differentiated cardiomyocytes. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses revealed that the genes significantly upregulated at cardiac lineage commitment were associated with responses to organic substances and external stimuli, extracellular and myocardial contractile components, receptor binding, gated channel activity, PI3K-AKT signaling, and cardiac hypertrophy and dilation pathways. Protein-protein interaction network analysis revealed that the expression levels of genes that regulate cardiac maturation, heart contraction, and calcium handling showed a consistent increase during cardiac differentiation; however, the expression levels of genes that regulate cell differentiation and multicellular organism development decreased at the cardiac maturation stage following lineage commitment. Additionally, we identified for the first time the protein-protein interaction network connecting cardiac development, the immune system, and metabolism during cardiac lineage commitment in both mESC-derived PDGFRα⁺ CLCs and hiPSC-derived KDR⁺PDGFRα⁺ CPCs. These findings shed light on the regulation of cardiac lineage commitment and the pathogenesis of cardiometabolic diseases.

• Korean Journal of Veterinary Research
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• v.41 no.4
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• pp.485-495
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• 2001

It was investigated whether $Ca^{2+}$ and $K^+$ channels were involved in the inhibitory action of nitric oxide (NO) on the contractile and slow wave activity of guinea pig gastric antral circular muscle. The gastric antral circular muscle showed spontaneous phasic contraction and slow wave. NO donors, 3-morpholinosydnonimine hydrochloride (SIN-1, $0.01{\sim}100{\mu}M$) and S-nitroso-L-cysteine (CysNO, $0.001{\sim}10{\mu}M$), reduced not only the amplitude of phasic contraction but also that of slow wave in a concentration-dependent manner. Both the perfusion of $Ca^{2+}$-free solution and the administration of $Ni^{2+}$, a nonselective $Ca^{2+}$ channel blocker, reduced the phasic contraction as well as the amplitude and frequency of the slow wave. The effects of these treatments were similar to those of NO donors. Nifedipine ($10{\mu}M$), a specific L-type $Ca^{2+}$ channel blocker, abolished the phasic contraction and remarkably reduced the plateau of slow wave but had no profound effect on the upstroke of slow wave. In the whole-cell patch clamp mode, CysNO shifted the steady-state activation curve for L-type $Ca^{2+}$ current to the right and the steady-state inactivation curve to the left. Pretreatment of various $K^+$ channel blockers such as tetraethylammonium (1 mM), 4-aminopyridine (0.5 mM), glibenclamide (10 mM), apamin ($0.1{\mu}M$), and iberiotoxin ($0.1{\mu}M$) did not affect the inhibitory action of SIN-1. These results suggest that NO donors suppress mechanical and electrical activity of guinea pig gastric antral circular muscle by inhibition of L-type $Ca^{2+}$ channel rather than by activation of $K^+$ channels.

• The Korean Journal of Physiology and Pharmacology
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• v.1 no.5
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• pp.529-535
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• 1997

The present study was aimed at investigating whether the vascular calcium regulation is altered in hypertension. Two-kidney, one clip (2K1C) and deoxycorticosterone acetate (DOCA)-salt hypertension were made in rats, and their thoracic aortae were taken 4 weeks later. The isometric contractile response and calcium uptake of the endothelium-denuded aortic preparations were determined. Caffeine ($0.1{\sim}35\;mmol/L$) induced a greater contraction in 2K1C and DOCA-salt hypertension than in normotensive control. When the vascular calcium store was functionally-depleted by a repeated exposure to caffeine, it took longer to reload the store and to resume the initial contraction force in response to caffeine in both 2K1C and DOCA-salt hypertension. The vascular $^{45}Ca$ uptake following the functional depletion of the cellular store was also greater in both models of hypertension than in control. Ryanodine, calcium channel activator of the sarcoplasmic reticulum, attenuated the restoration of caffeine-induced vascular contraction, which was not affected by either 2K1C or DOCA-salt hypertension. Nifedipine, an L-type $Ca^{2+}$ channel blocker, attenuated the restoration of caffeine-induced contraction, which was not affected by DOCA-salt hypertension, but was more pronounced in 2K1C hypertension. Nifedipine also diminished the vascular $^{45}Ca$ uptake, which was not affected by DOCA-salt hypertension, but was more pronounced in 2K1C hypertension. Ouabain, a $Na^+,\;K^+-ATPase$ inhibitor, increased the caffeine-induced contraction by a similar magnitude in control and 2K1C hypertension, which was, however, markedly attenuated in DOCA-salt hypertension. Ouabain enhanced the vascular $^{45}Ca$ uptake, the degree of which was not affected by 2K1C hypertension, but was markedly attenuated in DOCA-salt hypertension compared with that in control. Cyclopiazonic acid, a selective inhibitor of $Ca^{2+}-ATPase$ of the sarcoplasmic reticulum, attenuated the restoration of caffeine-induced contraction, which was not affected by 2K1C hypertension, but was more marked in DOCA-salt hypertension. These results suggest that the increased vascular calcium storage may be attributed to an enhanced calcium influx in 2K1C hypertension, and to an impaired $Na^+-K^+$ pump activity of the cell membrane and subsequently increased calcium pump activity of the cellular store in DOCA-salt hypertension.

• The Korean Journal of Physiology and Pharmacology
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• v.5 no.5
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• pp.397-405
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• 2001

The ryanodine receptor, a $Ca^{2+}$ release channel of the sarcoplasmic reticulum (SR), is responsible for the rapid release of $Ca^{2+}$ that activates cardiac muscle contraction. In the excitation-contraction coupling cascade, activation of SR $Ca^{2+}$ release channel is initiated by the activity of sarcolemmal $Ca^{2+}$ channels, the dihydropyridine receptors. Previous study showed that the relaxation defect of diabetic heart was due to the changes of the expressional levels of SR $Ca^{2+}$ATPase and phospholamban. In the diabetic heart contractile abnormalities were also observed, and one of the mechanisms for these changes could include alterations in the expression and/or activity levels of various $Ca^{2+}$ regulatory proteins involving cardiac contraction. In the present study, underlying mechanisms for the functional derangement of the diabetic cardiomyopathy were investigated with respect to ryanodine receptor, and dihydropyridine receptor at the transcriptional and translational levels. Quantitative changes of ryanodine receptors and the dihydropyridine receptors, and the functional consequences of those changes in diabetic heart were investigated. The levels of protein and mRNA of the ryanodine receptor in diabetic rats were comparable to these of the control. However, the binding capacity of ryanodine was significantly decreased in diabetic rat hearts. Furthermore, the reduction in the binding capacity of ryanodine receptor was completely restored by insulin. This result suggests that there were no transcriptional and translational changes but functional changes, such as conformational changes of the $Ca^{2+}$ release channel, which might be regulated by insulin. The protein level of the dihydropyridine receptor and the binding capacity of nitrendipine in the sarcolemmal membranes of diabetic rats were not different as compared to these of the control. In conclusion, in diabetic hearts, $Ca^{2+}$ release processes are impaired, which are likely to lead to functional derangement of contraction of heart. This dysregulation of intracellular $Ca^{2+}$ concentration could explain for clinical findings of diabetic cardiomyopathy and provide the scientific basis for more effective treatments of diabetic patients. In view of these results, insulin may be involved in the control of intracellular $Ca^{2+}$ in the cardiomyocyte via unknown mechanism, which needs further study.

• The Journal of Internal Korean Medicine
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• v.29 no.1
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• pp.117-129
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• 2008

Background & Objective : Naeso-san(NSS) has been used for the treatment of functional dyspepsia, regarded as a gastric dysmotility disease. A main cause of gastric dysmotility is antral dilatation or antroduodenal uncoordination. Therefore, we investigated the effect of NSS on gastric motility and its mechanism of action, as well as the morphologic changes in antral dilatated rats. Methods : Antral dilatated rats were induced by wrapping a nonabsorbable rubber ring(D:6mm, W:4mm, T:1mm) around the 1st portion of the duodenum for 8 weeks. Then morphologic changes were investigated and compared with normal intact rats before and after 8 weeks. Gastric emptying was measured by administration of normal saline(NS) or NSS in normal intact and antral dilatated rats. In another series of experiments to evaluate the mechanism of NSS under delayed conditions, normal intact rats were treated with atropine sulfate(1mg/kg, s.c.), quinpirole HCl(0.3mg/kg, i.p.), $NAME(N^{G}-nitro-L-arginine$ methyl ester, 75mg/kg, s.c.) and cisplatin(10mg/kg, i.p.), respectively. The myoelectrical activity of the gastric smooth muscle was recorded in normal intact and antral dilatated rats. The contractile waves were measured for 30 minutes before and after administration of each solution(NS, NSS). Results : Body weight gain of antral dilatated rats was significantly lower than that of the controls. Futhermore, we found the thickness of the mucosal and muscular layers and surface area of the stomach increased significantly compared with controls. NSS 278㎎/㎏ improved gastric emptying more than normal saline or NSS 93mg/kg in normal intact(p=0.026) and antral dilatated rats(p=0.03). NSS enhanced gastric emptying significantly in the NAME treated group(p=0.002). NSS 278mg/kg increased the significant postprandial dominant power than that of NS in normal intact rats, whereas there was no statistical significance in antral dilatated rats. Conclusions : NSS stimulates gastric motility through the cholinergic pathway. We expect that pathologic model with antral dilatation can be used as an exprimental tool which is similar to dyspepsia and NSS would be effective especially in dysmotility-like functional dyspepsia with antral dilatation or impaired reservoir functions such as gastric adaptive relaxation.

• Journal of Life Science
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• v.22 no.3
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• pp.387-397
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• 2012

In this study, we focused on myomoduline A (MMA) released from the central nervous system of Aplysia kurodai. The primary structure of MMA is Pro-Met-Ser-Met-Leu-Arg-Leu-$NH_2$. This peptide is the same as that of the myomodulin family peptide found in other mollusks. The purified MMA showed a modulating activity of phasic contraction on the anterior byssus retractor muscle (ABRM) of Mytilus edulis. In order to study the relationship between the structure and biological activity of MMA, we synthesized MMA, Des[$Pro^1$]-MMA, Des[$Pro^1,Met^2$]-MMA, Des[$Pro^1,Met^2,Ser^3$]-MMA, and MME. The amino acid sequences of Des[$Pro^1$]-MMA, Des[$Pro^1,Met^2$]-MMA, and Des[$Pro^1,Met^2,Ser^3$]-MMA were Met-Ser-Met-Leu-Arg-Leu-$NH_2$, Ser-Met-Leu-Arg-Leu-$NH_2$, and Met-Leu-Arg-Leu-$NH_2$, respectively. MMA and synthetic peptides were tested on ABRM in M. edulis as well as muscle preparations in Achatina fulica. At $1{\times}10^{-8}$ M or lower, MMA showed a potentiating effect on phasic contraction of the ABRM, but this peptide had an inhibitory effect at $1{\times}10^{-6}$ M or higher. Both MMA and its analogs stimulated a contractile response on the crop and a relaxed catch-relaxing response on the penial retractor muscle of A. fulica. These results suggest that Met-Leu-Arg-Leu-$NH_2$ in MMA is the minimum structure required for the regulation of the contraction of ABRM, as well as the reproductive and digestive activities of mollusks.

• Korean Journal of Ichthyology
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• v.26 no.3
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• pp.171-178
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• 2014

Myogenesis is the formation process of multinucleated myofiber with a contractile capacity from muscle satellite cell (MSCs) during life. This process is tightly controlled by several transcription factors such as Pax3 and Pax7 (paired box protein 3 and 7), MEF2C (myocyte enhancer factor 2) and MRFs (myogenic regulatory factors) etc. On the contrary, myostatin (MSTN) is a transforming growth factor-${\beta}$ superfamily, which functions as a negative regulator of skeletal muscle development and growth. Carnosic acid (CA) is a major phenolic component in rosemary (Rosmarinus officinalis) and have been reported various biological activities such as anticancer, antioxidant, antimicrobial and therapeutic agents for amnesia, dementia, alzheimer's disease. This study was confirmed to effects of CA on muscle cell line and muscle tissue alteration of zebrafish by intramuscular injection or feeding methods. $10{\mu}M$ CA showed a non-cytotoxic on myoblast and a complete inhibition effect against myostatin activity on luciferase assay. In intramuscular injection experiment, the total protein and triglyceride amount of $10{\mu}M/kg$ of CA injected group increased by 11% and decreased by 13% compared to these of the no injected group. In histology analysis of muscle tissues by hematoxylin/eosin staining, the number of muscle fiber of $10{\mu}M/kg$ of CA injected group decreased by 29% and fiber area increased 40% compared to these of no injected group. In feeding experiment, the total protein and triglyceride amount no significance difference compared to these of the normal feeding group. In histology analysis, the number of muscle fiber of 1% CA fed group decreased by 35% and fiber area increased 56% compared to these of normal fed group. We identified that CA have an effect on hypertrophy of muscle fiber in adult zebrafish and the results of this study are considered as the basic data that can reveal the mechanisms of muscle formation via gene and protein level analysis.

• Journal of Physiology & Pathology in Korean Medicine
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• v.27 no.5
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• pp.602-610
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• 2013

This study was aimed to evaluate the cavernosal relaxation effect of Crataegii fructus(CF) in the contracted rabbit penile corpus cavernosum by agonists.In order to study the effect of CF on the vasoconstriction of rabbit penile corpus cavernosum, isolated rabbit penile corpus cavernosum tissues were used for the experiment using organ baths containing Krebs solution.To investigate the cavernosal relaxation of CF, CF extract at $0.01{\sim}3.0mg/m{\ell}$ was added after penile corpus cavernosum were contracted by norepinephrine(NE) $1{\mu}M$. To analyze the mechanism of CF's vasorelaxation, CF extract infused into contracted penile tissues by NE after each treatment of indomethacin(IM), $N{\omega}$-nitro-L-arginine(L-NNA), methylene blue(MB), tetraethylammonium chloride(TEA).To study the effect of CF on influx of extracellular calcium chloride($Ca^{2+}$) in penile tissues, in $Ca^{2+}$-free krebs solution, $Ca^{2+}$ 1 mM infused into contracted penile tissues by NE after pretreatment of CF. Cytotoxic activity of CF on human umbilical vein endothelial cell(HUVEC) was measured by MTT assay, and nitric oxide(NO) prodution was measured by Griess reagent. CF relaxed cavernosal strip with endothelium contracted by NE, but in the strips without endothelium, CF-induced relaxation was significantly inhibited. The pretreatment of L-NNA, MB, TEA decreased significantly on the cavernosal relaxation than not-treatment of them. But the pretreatment of IM had no significant effect on the cavernosal relaxation. In $Ca^{2+}$-free krebs solution, when $Ca^{2+}$ infused into contracted penile tissues by NE, pretreatment of CF inhibit contraction induced by adding $Ca^{2+}$.NO production wasn't increased by treatment of CF on HUVEC. This findings showed that CF is effective for the relaxation of rabbit penile corpus cavernosum, and we suggest that CF relax rabbit corpus cavernosal smooth muscle through multiple action mechanisms that include increasing the release of nitric oxide from corporal sinusoidal endothelium, inhibition of $Ca^{2+}$ mobilization into cytosol from the extracellular fluid, and maybe a hyperpolarizing action.

• Journal of Physiology & Pathology in Korean Medicine
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• v.27 no.4
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• pp.400-408
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• 2013

This study aimed to investigate the relaxation effects and its underlying mechanisms of Rubus coreanus(RC) extract in contracted rabbit corpus cavernous tissues by phenylephrine(PE) $1{\mu}M$. In order to define the relaxation effects of RC, rabbit corpus cavernous tissues were prepared in $2{\times}2{\times}6mm$ sized strip. The dose-dependent relaxation responses of RC at 0.01-3.0 $mg/m{\ell}$ in contracted strips induced by PE were measured and also observed after endothelial denudation. To analyze the underlying mechanisms of RC-induced relaxation, indomethacin(IM), tetraethylammonium chloride(TEA), $N{\omega}$-nitro-L-arginine (L-NNA), methylene blue(MB) were treated before RC extract infused into precontracted strips induced by PE. To study the effect of RC extract on influx of extracellular $Ca^{2+}$ in corpus cavernous strips, calcium chloride(Ca) 1 mM infused into precontracted strips induced by PE after pretreatment of RC extract in $Ca^{2+}$-free krebs-ringer solution. To investigate cytotoxic activity and nitric oxide(NO) concentration of RC extract on human umbilical vein endothelial cell(HUVEC), cell viability on HUVEC was measured by MTT assay, and NO concentration was measured by Griess reagent system. The cavernous strips were significantly relaxed by RC extract at 1.0 $mg/m{\ell}$, 3.0 $mg/m{\ell}$ and the relaxation responses to RC were inhibited significantly by endothelial disruption. The pretreatment of IM, TEA didn't affect RC extract-induced endothelium-dependent relaxation, but the pretreatment of L-NNA, MB reduced RC extract-induced endothelium-dependent relaxation. When $Ca^{2+}$ was supplied the cavernous strips which were precontracted by PE in a $Ca^{2+}$-free krebs-ringer solution, contraction of strips was increased, but pretreatment of RC inhibited contractile response to $Ca^{2+}$. When RC extract was applicated on HUVEC, NO concentration was increased. Our findings show that RC extract exerts a relaxing effect on corpus cavernosum in part by suppressing influx of extracellular $Ca^{2+}$ through activating the NO-cGMP system.

• The Korean Journal of Pharmacology
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• v.24 no.2
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• pp.189-195
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• 1988

This study aimed to investigate the autonomic innervations of human vas deferens and the effect of diazepam, a benzodiazepine sedative antianxiety drug, on the smooth muscle contractility of vas deferens. The specimens were obtained from healthy volunteers undergoing elective vasectomy with local anesthesia. The muscle preparation did not show any spontaneous contraction, but showed a good contraction induced by norepinephrine exerting the strongest response at $33^{\circ}C$. Phentolamine inhibited the norepinephrine-induced contraction concentration-dependently. Isoproterenol, a beta-adrenergic agonist evoked a considerable extent of contraction, and this contractile activity was antagonized by propranolol, a beta-adrenergic blocking agent. Acetylcholine induced a dashing contraction of the human vas deferens, and atropine, a muscarinic receptor blocking agent abolished the acetylcholine-induced contraction. Diazepam inhibited the norepinephrine-induced contraction in a concentration dependent manner. These results suggest that the smooth muscle of human vas deferens has cholinergic muscarinic and beta adrenergic receptors as well as the predominant alpha adrepergic receptor. Diazepam inhibits the motility, especially norepinephrine-induced contraction of human vas deferens.