• Journal of Industrial Convergence
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• v.21 no.10
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• pp.57-63
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• 2023

This study aims to elucidate the effect of glycyrrhizic acid on smooth muscle contraction and to determine the detailed mechanism incorporated. We hypothesized that glycyrrhizic acid played a role in the agonist-sensitive management of smooth muscle contraction. Stripped smooth muscles of Sprague-Dawley rats were prepared in organ baths and isometric tensions were converted, stored and analyzed by using isometric transducers, a physiograph and one way ANOVA. Interestingly, glycyrrhizic acid attenuated the thick filament regulating agonist (fluoride or thromboxane mimetic)-sensitive contraction (p=0.113, 0.008, 0.004 (Student's t-test), p=0.113, 0.008, 0.004 (One way ANOVA) at 0.01, 0.03, 0.1 mM fluoride, and p=0.156, 0.004, 0.003 (Student's t-test), p=0.156, 0.004, 0.003 (One way ANOVA) at 0.01, 0.03, 0.1 mM thromboxane mimetic) and did not attenuate the thin filament regulating agonist (phorbol ester)-induced contraction (p=0.392, 0.086, 0.065 (Student's t-test), p=0.392, 0.086, 0.065 (One way ANOVA) at 0.01, 0.03, 0.1 mM phorbol ester). It is suggesting that endothelial EDRF (NO) synthesis and accessory pathways besides endothelial EDRF (NO) synthesis such as ROCK restriction might be incorporated in the glycyrrhizic acid-induced modulation of smooth muscle contraction inhibiting acto-myosin interaction.

• Korean Journal of Veterinary Research
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• v.43 no.3
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• pp.405-414
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• 2003

The purpose of this study was to assess the role of tachykinins (TK) in mediating nonadrenergic noncholinergic (NANC) contractions produced by electrical field stimulation (EFS) in the longitudinal muscle of the rat ileum. In the presence of atropine ($1{\mu}M$), guanethidine ($5{\mu}M$), and L-nitroarginine (L-NNA, $200{\mu}M$), EFS (0.5ms pulse duration, 120 V, 1-20 Hz for 2 min) produced a frequency-dependent slowly-developing tonic contraction with superimposed phasic contractions ('on'-contraction) followed by off slowly-decreasing tonic and superimposed phasic contractions ('off'-contraction) of mucosa-free longitudinal oriented muscle strip. These EFS induced responses were blocked by tetrotoxin. $NK_1$ receptor selective antagonist L-732,138 strongly inhibited the EFS-induced excitatory responses. However $NK_2$ receptor selective antagonist, GR 159897 and $NK_3$ receptor selective antagonist SB 222200 did not significantly inhibited the responses. $NK_1$ receptor selective agonist [$Sar^9$,$Met(O_2)^{11}$] Substance P and $NK_2$ receptor selective agonist [${\beta}-Ala^8$]-neurokinin A (4-10) induced tonic contraction with superimposed phasic contractions of longitudinal oriented muscle strip and almost blocked by selective antagonist L-732,138 and GR 159897, respectively. But $NK_3$ receptor selective agonist senktide did not showed any effect. Nifedipine ($1{\mu}M$) abolished the contraction produced either by EFS or by the TK receptor agonists [$Sar^9$,$Met(O_2)^{11}$] Substance P or [${\beta}-Ala^8$]-neurokinin A (4-10). It is concluded that, in the longitudinal muscle of rat ileum, both $NK_1$ and $NK_2$ receptors modulated the responses to exogenous tachykinins, whereas $NK_1$ is mainly involved in NANC neuromuscular contraction.

• The Korean Journal of Physiology and Pharmacology
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• v.15 no.1
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• pp.31-36
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• 2011

To understand the roles of purinergic receptors and cellular molecules below the receptors in the vascular inflammatory response, we determined if extracellular nucleotides up-regulated chemokine expression in vascular smooth muscle cells (VSMCs). Human aortic smooth muscle cells (AoSMCs) abundantly express $PSY_1$, $PSY_6$, and $PSY_{11}$ receptors, which all respond to extracellular nucleotides. Exposure of human AoSMCs to $NAD^+$, an agonist of the human $PSY_{11}$ receptor, and $NADP^+$ as well as ATP, an agonist for $PSY_1$ and $PSY_{11}$ receptors, caused increase in chemokine (C-C motif) ligand 2 gene (CCL2) transcript and CCL2 release; however, UPT did not affect CCL2 expression. CCL2 release by $NAD^+$ and $NADP^+$ was inhibited by a concentration dependent manner by suramin, an antagonist of P2-purinergic receptors. $NAD^+$ and $NADP^+$ activated protein kinase C and enhanced phosphorylation of mitogen-activated protein kinases and Akt. $NAD^+$- and $NADP^+$-mediated CCL2 release was significantly attenuated by SP6001250, U0126, LY294002, Akt inhibitor IV, RO318220, GF109203X, and diphenyleneiodium chloride. These results indicate that extracellular nucleotides can promote the proinflammatory VSMC phenotype by up-regulating CCL2 expression, and that multiple cellular elements, including phosphatidylinositol 3-kinase, Akt, protein kinase C, and mitogen-activated protein kinases, are involved in that process.

• Journal of Korean Physical Therapy Science
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• v.24 no.1
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• pp.69-78
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• 2017

Background: The purpose of the present study is to report the effect of muscle performance on knee flexion and extension by chin in exercise. Methods: This study was Participated in 10 healthy subjects. For conducting the chin-in exercise, subjects are lay down with supine position. Using the rounded towel, subjects was performed contraction of longus colli and longus capatis muscle by push the towel. Chin-in exercise was conducted 3 times a day, 4 times a week for 4 weeks. By using the Biodex system4, We measured absolute muscle strength, relative muscle strength, total exercise quantity and average rate of production in knee flexion and extension. The data was analyzed by the repeated-measure ANOVA for comparing before, after exercise 2 weeks, after exercise 4 weeks changes of factors. Results: After chin-in exercise, there was significant difference of before, after 2 weeks and 4weeks results in absolute muscle strength, relative muscle strength, total exercise quantity, average rate of production, agonist/antagonist ratio(p<.05). Conclusion: As a results of this study, chin-in exercise may help to improve muscle ability of knee joint activation and knee joint action performance.

• Journal of Biomedical Engineering Research
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• v.44 no.3
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• pp.218-224
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• 2023

This study aimed to analyze the coordination of muscle and muscle fatigue between biceps, lateral deltoid, and anterior deltoid during dumbbell side lateral raise using bio-signal. One male subject performed dumbbell side lateral raise with 3% of 1RM dumbbell at the rate of 30bpm until failure (8 minutes). While performing, ECG were recorded to observe the participant's performance. EMG were recorded from biceps, lateral deltoid, and anterior deltoid for observing coordination and fatigue. ECG were analyzed in time and frequency domain to observe Heart rate, normLF, normHF. Changes in heart rate, normLF, and normHF indicate that the sympathetic nervous system is activated, while changes in median frequency (MDF) indicate the occurrence of muscle fatigue. Moreover, the coordination relationship of muscle changed. The correlation of MDF between each muscles indicated that lateral deltoid is associated with biceps and anterior deltoid. These results showed that our study can contribute to improving understanding of muscle fatigue and muscle coordination relationships.

• Molecules and Cells
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• v.27 no.2
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• pp.191-198
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• 2009

The present study was undertaken to determine whether treatment with genistein, the plant-derived estrogen-like compound influences agonist-induced vascular smooth muscle contraction and, if so, to investigate related mechanisms. The measurement of isometric contractions using a computerized data acquisition system was combined with molecular experiments. Genistein completely inhibited KCl-, phorbol ester-, phenylephrine-, fluoride- and thromboxane $A_2$-induced contractions. An inactive analogue, daidzein, completely inhibited only fluoride-induced contraction regardless of endothelial function, suggesting some difference between the mechanisms of RhoA/Rho-kinase activators such as fluoride and thromboxane $A_2$. Furthermore, genistein and daidzein each significantly decreased phosphorylation of MYPT1 at Thr855 had been induced by a thromboxane $A_2$ mimetic. Interestingly, iberiotoxin, a blocker of large-conductance calcium-activated potassium channels, did not inhibit the relaxation response to genistein or daidzein in denuded aortic rings precontracted with fluoride. In conclusion, genistein or daidzein elicit similar relaxing responses in fluoride-induced contractions, regardless of tyrosine kinase inhibition or endothelial function, and the relaxation caused by genistein or daidzein was not antagonized by large conductance $K_{Ca}$-channel inhibitors in the denuded muscle. This suggests that the RhoA/Rho-kinase pathway rather than $K^+$- channels are involved in the genistein-induced vasodilation. In addition, based on molecular and physiological results, only one vasoconstrictor fluoride seems to be a full RhoA/Rho-kinase activator; the others are partial activators.

• Archives of Pharmacal Research
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• v.29 no.5
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• pp.400-404
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• 2006

This study examined the effect of Gamma-Amino butyric acid (GABA) and selective GABA receptor related drugs on the electrically stimulated relaxation in the lower esophageal sphincter muscle (LES) of a cat. Tetrodotoxin $(10^{-6}\;M)$ suppressed the electrically stimulated (0.5-5 Hz) relaxation of the LES. However, guanethidine $(10^{-6}\;M)$ and atropine $(10^{-6}\;M)$ had no effect indicating that the relaxations were neurally mediated via the nonadrenergic and noncholinergic (NANC) pathways. NG-nitro-L-arginine methyl ester ($10^{-4}M$, L-NAME) also inhibited the relaxant response but did not completely abolish the electrically stimulated relaxation with 60% inhibition, which suggests the involvement of nitric oxide as an inhibitory transmitter. This study examined the role of GABA, an inhibitory neurotransmitter, on neurally mediated LES relaxation. GABA ($10^{-3}-10^{-5}M$, non selective receptor agonist), muscimol ($10^{-3}-10^{-5}M$, GABA-A agonist), and baclofen ($10^{-3}-10^{-5}M$, GABA-B agonist) had no significant effect on the electrically stimulated relaxation. Moreover, bicuculline ($10^{-5}M$, GABA-A antagonist) and phaclofen ($10^{-5}M$, GABA-B antagonist) had no inhibitory effect on the electrically stimulated relaxation. This suggests that GABA and the GABA receptor are not involved in the electrically stimulated NANC relaxation in the cat LES.

• Biomedical Science Letters
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• v.19 no.1
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• pp.17-24
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• 2013

Animals show a sexual dimorphism in metabolic responses. We investigated to verify whether the peroxisome proliferator-activated receptor ${\alpha}$ ($PPAR{\alpha}$) agonist fenofibrate regulates obesity and skeletal muscle lipid metabolism with sexual dimorphism and to determine the changes in skeletal muscle expression of $PPAR{\alpha}$ target genes. After both sexes of C57BL/6J mice received a high fat diet with or without fenofibrate for 7 weeks, we examined the effects of fenofibrate on not only body weight, adipose tissue mass, and skeletal muscle lipid accumulation, but also the mRNA expression of $PPAR{\alpha}$-related genes in skeletal muscle. Male mice given a fenofibrate-supplemented high fat diet showed decreased body weight gain and adipose tissue mass compared with mice fed a high fat diet alone, whereas fenofibrate did not reduce them in high fat diet-fed female mice. Lipid accumulation in skeletal muscle was inhibited by fenofibrate in male mice, but not in female mice. Gene expression analysis revealed that fenofibrate increased the mRNA levels of $PPAR{\alpha}$ target enzymes only in male mice. Therefore, our results suggest that sex-dependence differences in obesity and intramuscular lipid levels under fenofibrate treatment could be due in part to the differences in skeletal muscle $PPAR{\alpha}$ activation between male and female mice.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.35 no.2
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• pp.88-97
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• 2012

The muscle strengths in various postures are still used in the workplace, although mechanization and automation have been continuously accomplished. The aim of this study is to measure the maximum muscle strength and analyze the muscle fatigue during the various wrench jobs which are one of the upper limbs related works. Four hundreds and eighty five college students (243 males and 242 females) participated in this study. Twelve muscle strengths which are using for pulling, pushing, lifting and lowering the wrench with various postures are measured. For every moment, the muscle strengths for both hands were measured. In each measurement, five seconds averaged value and peak value were collected. The averaged value of preferred hand and non-preferred hand was compared. Also, the averaged value of opposite movement was compared through t-test. The fatigue of agonist for each movement was analyzed using EMG analysis. The result of this study can provide some basic information not only in designing the tools in work but also in selection, training and management of workers.

• The Journal of Korean Physical Therapy
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• v.27 no.4
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• pp.234-239
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• 2015

Purpose: This study is not a fragmentary study on characteristics of respiratory synergist when breathing, however it was intended to determine the effect of currently available respiratory exercise and to provide basic clinical information through investigation of oxygen demand and respiratory synergist that mobilizes for respiration during application of respiratory exercise. Methods: Experimental group I was selected from second grade of severity classification of GOLD, which has the highest percentage among patients with COPD, and experimental group II was selected from third grade of severity classification as a clinical sampling. After respiration pursing up lips and diaphragm respiration exercise were mediated together for six weeks, activity of respiratory muscles and oxygen saturation were measured and analyzed. Results: In comparison of change of respiratory synergist and oxygen saturation, activity of respiratory synergist in sternocleidomastoid muscle and scalene muscle showed a meaningful decrease in experimental group I. And, in comparison of change of respiratory synergist and oxygen saturation, activity of respiratory synergist in rectus abdominis muscle showed a meaningful increase in experimental group II. In comparison of change of respiratory synergist and oxygen saturation, activity of respiratory synergist in sternocleidomastoid muscle, scalene muscle, and rectus abdominis muscle showed a meaningful difference between experimental groups. Conclusion: Respiratory synergists work mainly as agonist of chest and upper limbs. Therefore it is very important to lower mobilization of respiratory synergist when breathing. It is considered that a multilateral approach and continued clinical research for improvement of respiratory function for patients with COPD will be needed in the future.