• The Korean Journal of Physiology and Pharmacology
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• 제20권5호
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• pp.547-556
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• 2016

Myometrial relaxation of mouse via expression of two-pore domain acid sensitive (TASK) channels was studied. In our previous report, we suggested that two-pore domain acid-sensing $K^+$ channels (TASK-2) might be one of the candidates for the regulation of uterine circular smooth muscles in mice. In this study, we tried to show the mechanisms of relaxation via TASK-2 channels in marine myometrium. Isometric contraction measurements and patch clamp technique were used to verify TASK conductance in murine myometrium. Western blot and immunehistochemical study under confocal microscopy were used to investigate molecular identity of TASK channel. In this study, we showed that TEA and 4-AP insensitive non-inactivating outward $K^+$ current (NIOK) may be responsible for the quiescence of murine pregnant longitudinal myometrium. The characteristics of NIOK coincided with two-pore domain acid-sensing $K^+$ channels (TASK-2). NIOK in the presence of $K^+$ channel blockers was inhibited further by TASK inhibitors such as quinidine, bupivacaine, lidocaine, and extracellular acidosis. Furthermore, oxytocin and estrogen inhibited NIOK in pregnant myometrium. When compared to non-pregnant myometrium, pregnant myometrium showed stronger inhibition of NIOK by quinidine and increased immunohistochemical expression of TASK-2. Finally, TASK-2 inhibitors induced strong myometrial contraction even in the presence of L-methionine, a known inhibitor of stretch-activated channels in the longitudinal myometrium of mouse. Activation of TASK-2 channels seems to play an essential role for relaxing uterus during pregnancy and it might be one of the alternatives for preventing preterm delivery.

• 한국운동역학회지
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• 제24권2호
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• pp.139-149
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• 2014

The purpose of this study was to evaluate the effect of angle change of forefoot's adhesive outsole on the electromyographic activity (EMG) of the erector spinae and selected lower limbs muscle during downhill walking over $-20^{\circ}$ ramp. Thirteen male university students (age: $25.4{\pm}3.9$ yrs, height: $176.2{\pm}5.1$ cm, weight: $717.4{\pm}105.0$ N) who have no musculoskeletal disorder were recruited as the subjects. To assess the myoelectric activities of selected muscles, six of surface EMG electrodes with on-site pre-amplification circuitry were attached to erector spinae (ES), rectus femoris (RF), biceps femoris (BF), tibialis anterior (TA), lateral gastrocnemius (LG), and medial gastrocnemius (MG). To obtain maximum EMG levels of the selected muscles for normalization, five maximum effort isometric contraction were performed before the experimental trials. Each subject walked over $0^{\circ}$ and $20^{\circ}$ ramp with three different forefeet's EVA outsole (0, 10, $20^{\circ}$) in random order at a speed of $1.2{\pm}0.1$ m/s. For each trial being analyzed, five critical instants and four phases were identified from the recording. The results of this study showed that the average muscle activities of MG and LG decreased in $20^{\circ}$ shoes compared to $0^{\circ}$ and $10^{\circ}$ ones in the initial double limb stance (IDLS). In initial single limb stance (ISLS) phase, the average muscle activities of ES increased with the angle of forefoot's adhesive outsole, indicating that the increment of shoes' angle induce upper body to flex anteriorly in order to maintain balance of trunk. In terminal double limb stance (TDLS) phase, average muscle activities of TA significantly increased in $20^{\circ}$ outsole compared to $0^{\circ}$ and $10^{\circ}$ ones. There was no external forces acting on the right foot other than the gravity during terminal single limb stance (TSLS) phase, all muscles maintained moderate levels of activity.

• The Journal of Korean Physical Therapy
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• 제23권1호
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• pp.21-28
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• 2011

Purpose: The aim of this study was to investigate correlations between the Functional Movement Screen (FMS), pain, and performance ability in professional fencing players. Methods: Fifty-six athletes participated in this study. The pain group included those who had a score on a pain-related Visual Analogue Scale (VAS) of ${\geq}$20 and an Oswestry Disability Index (ODI) score ${\geq}$10). In the non-pain group, these scores were: VAS(<20), ODI(<10). The VAS and ODI were used to measure pain throughout the study. Performance ability included motor function of the lower extremities (as assessed by a Modified Functional Index Questionnaire, MFIQ), dynamic balance (Balance system, BS and Posture med, PM), flexor and extensor muscle strength of the lumbar region was recorded as maximal isometric strength. Results: Among athletes who had pain, 5 of 15(33.33%) showed impaired functional movement. Conversely, only 2 of 41(4.88%) of those who had no pain showed such impairment (FMS ${\leq}$14score). The athletes who had pain and who had an FMS score above 14 (10/56; 17.86%) showed a significantly higher score for extensor muscle strength of the lumbar compared with those with pain and an FMS score below 14 (5/56; 8.93%) were significant correlations between the FMS and pain (r=-0.40 to -0.42, p<0.01), the MFIQ (r=-0.33, p<0.05), dynamic balance (r=-0.27 to -0.40, p<0.05-0.01), muscle strength of the lumbar (r=0.27 to 0.29, p<0.05). Stepwise multiple regression analysis showed that the dynamic balance score (${\beta}{\beta}$=-0.41) had slightly more power in predicting FMS score than pain, motor function of lower extremity, or muscle strength. Conclusion: The FMS was significantly associated with values of pain, motor function of the lower extremities, dynamic balance, and muscle strength of the lumbar. However the FMS appears to lack relevance and reasonable evidence to suggest that it is an acceptable measurement tool for functional movement analysis.

• Journal of Chest Surgery
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• 제29권12호
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• pp.1299-1305
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• 1996

고칼륨과 저온이 혈관내피세포의 acetylcholine(Ach)에 의한 혈관이완에 미치는 영향을 알아보기 위하여 흰쥐의 흉부 대동맥을 이용하여 Ach과 sodium nitroprusside(SNP)에 대한 이완 반응을 측정하였다. 실험은 다섯 군으로 나누어서 실시하였으며 각 군을 10례로 하였다. 1군은 대조군으로 어떤 조작도 가하지 않고 organ bath에서 등랑성 긴장도를 측정하였고, 2군(내피세포 제거군)은 내피세포를 물리적으로 제거후 1군과 같은 방법으로 긴장도를 측정하였고, 37$^{\circ}C$ 57에 45분간 처리후 혈관의 등장성 긴장도를 측정하였다. 대조군, 457,4mST및 3757군에서의 Ach에 대한 혈관의 이완은 유의한 차이가 없었으며,내피세포 제거군에서는 Ach에 대한 혈관의 이완이 대조군에 비해 현저하게 감소되었으며, SUP에 대한 혈관의 이완은 모든 군에서 유의한 차이가 없었다. 이에 저자들은 다음과 같은 결론을 내릴 수 있었다. 고농도의 칼륨과 저온자체는 흰쥐의 흉부대동맥 내피세포의 Ach에 대한 이완능을 저해하지 않는다.

• Journal of Korean Neurosurgical Society
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• 제29권4호
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• pp.451-460
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• 2000

Objective : This experiment is aimed at clarifying the characteristics of spasmodic basilar arteries in the rabbits of subarachnoid hemorrhage(SAH) with observation of vascular response to nitric oxide(NO) and endothelin-1. Material and Methods : Seventy-nine New Zealand white rabbits were divided into 4 groups : control(n=17), sham operation(n=13), postictal-2-day(n=25), and postictal-7-day group(n=24). Rabbits in the postictal-2-day group and postictal-7-day group underwent transfemoral vertebral angiography 2 days and 7 days after SAH respectively. A vascular ring of spasmodic basilar artery was harvested and suspended in organ chamber($37^{\circ}C$) to observe isometric tension changes in response to NO and endothelin-1 under both high(95% $O_2$/5% $CO_2$) and low(95% $N_2$/5% $CO_2$) $O_2$ tension. To investigate the vascular response to NO, acetylcholine from $10^{-7}M$ to $3{\times}10^{-4}M$ concentration was applied to basilar artery ring precontracted with histamine $10^{-6}-10^{-5}M$ in the organ chamber. The vascular response to endothelin-1 was observed by applying endothelin-1 from $10^{-11}M$ to $3{\times}10^{-8}M$ concentration into organ chamber. Results : Seven of 15 live rabbits which underwent angiography 2 days after SAH, were confirmed to develop vasospasm($64.3{\pm}11.2%$) whereas seven of 13 live rabbits which underwent angiography 7 days after SAH, were confirmed to develop vasospasm($64.9{\pm}10.9%$). In all groups, hypoxia significantly reduced the vascular relaxation of basilar arteries to NO. However, hypoxia made no influence on the vascular contraction of basilar arteries to endothelin-1 in all groups. In vascular relaxation of basilar arteries to NO under high $O_2$ tension between groups, the maximum relaxation of basilar arteries in the postictal-7-day group was significantly reduced compared to the postictal-2-day group. In vascular contraction of basilar arteries to endothelin-1 under high $O_2$ tension between groups, the maximum contraction of basilar arteries in the postictal-7-day group was significantly reduced compared to the postictal-2-day group. Conclusions : This experiment suggests that the characteristics of vascular response to NO and endothelin-1 in the spasmodic basilar arteries of rabbits observed 2 days after SAH is different from those observed 7 days after SAH.

• 한국식품영양과학회지
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• 제35권7호
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• pp.847-852
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• 2006

KH204가 음경해면체 이완과 생식기능에 미치는 영향을 규명하기 위해 효능을 실험한 결과 토끼의 음경해면체를 $1{\times}10^{-6}M$ pheylephrine으로 수축시킨 후 KH204를 61, 183 및 549 mg/L의 축적용량으로 처리하여 각각 6.8, 10.1 및 16%의 용량의존적인 이완효과를 관찰하였다. 흰쥐를 이용한 생식기능 실험은 KH204를 61, 183 및 549 mg/kg으로 10주간 장기투여에서 생식장기인 고환조직의 중량 및 정자수 증가에 유의한 효과를 나타내었다. 정자 형태검사는 대조군과 비슷한 수치로 나타내어 고농도로 장기투여에도 정자군과 비슷한 수치로 나타내어 고농도로 장기투여에도 정자 기형에 문제가 없음을 확인하였다. 이상의 결과로 KH204가 특별한 부작용이 없이 음경해면체를 농도의존적으로 이완시키는 효과가 있어, 음경발기를 개선시키는 효과뿐만 아니라 고환성 원인 또는 정자생산 기능부전으로 보이는 남성불임에서 또한 효능이 있음을 시사하였다.

• Journal of Yeungnam Medical Science
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• 제12권2호
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• pp.246-259
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• 1995

배뇨근의 운동성에 대한 baclofen의 억제작용의 기전을 탐구하기 위하여 다음과 같은 실험을 하였다. 흰쥐 (Sprague-Dawley)의 방광에서 적출한 배뇨근절편을 적출근편실험조에 현수하고, 등척성 장력측정기를 사용하여 그 수축력을 묘기하였다. 실험조내의 영양액의 온도는 $37^{\circ}C$로 유지시키고, 95% 산소와 5% 이산화탄소의 혼합기체를 공급하여 pH를 7.4로 유지하였다. 배뇨근절편은 전기장자극에 의해 수축하였는데, 8분간의 전기장자극 유발수축 중 최초의 급격한 수축반응은 mATP와 baclofen에 의해 약간 억제되는 경향을 보였으며, 후기 4분간의 수축반응은 콜린성 무스카린성 수용체 봉쇄제인 atropine과 $GABA_B$ 수용체 효현제인 baclofen에 의해 유의하게 억제되었다. Atropine은 배뇨근 절편의 acetylcholine 유발 수축을 길항하였고, mATP는 ATP 유발 수축을 완전히 봉쇄하였으나, baclofen 존재하에서는 acetylcholine이나 ATP 첨가에 의한 배뇨근의 수축이 영향을 받지 않았다. 이상의 결과를 종합하면, 흰쥐 방광에는 $GABA_B$ 수용체가 존재하며 baclofen은 이 수용체를 통하여 콜린성신경 말단에서의 신경전달체의 유리를 억제하여 배뇨근의 수축성을 감소시킨다고 사료된다.

• Physical Therapy Rehabilitation Science
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• 제8권1호
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• pp.45-51
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• 2019

Objective: The purpose of this study was to investigate the muscle activity ratio of the lower limb according to changes in straight leg raise (SLR) test angles on hamstring muscle shortening during squat exercises. Design: Randomized controlled trial. Methods: The subjects were 14 healthy adults who were informed of and agreed to the method and purpose of the study. The participants were classified into SLR groups according to two angles (over $80^{\circ}$ or under $80^{\circ}$) assessed using the SLR tests. After training and practicing the wall squat posture to be applied to the experiment, electromyography (EMG) was used to measure changes in muscle activity during the performance of a wall squat. After stretching, a sequence of pre-stretch tests were performed again, and the active and passive SLR tests were also reconducted; thereafter, a wall squat was performed again by attaching EMG electrodes. The EMG results before and after stretching were compared. Results: The muscle activity of the vastus lateralis oblique muscle increased in both groups. The muscle activity of the vastus medialis oblique muscle decreased in over both group. Rectus femorus activity increased in the under 80-degree groups but decreased in the over 80-degree group. The muscle activity of the biceps femoris muscle decreased after stretching in the over 80-degree group and increased in the under 80-degree group, and the semitendinosus muscle activity after stretching was decreased. The quadriceps-to-hamstring muscle (Q:H) ratio before and after stretching between groups showed that the hamstring muscle ratio decreased after stretching in both groups. Conclusions: The results of this study showed that the Q:H ratio before and after stretching between groups was not significantly different.

• 대한본초학회지
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• 제28권4호
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• pp.63-69
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• 2013

Objectives : The purpose of present study was to investigate the vasorelaxant activities and mechanisms of action of the ethanol extract of P. yedoensis leaf (PYL) on isolated rat aortic rings. Methods : Dried P. yedoensis leaves were extracted 3 times with 100% ethanol for 3 h in a reflux apparatus. Isolated rat aortic rings were suspended in organ chambers containing 10 ml Krebs-Henseleit (K-H) solution. The rings were maintained at $37^{\circ}C$ and aerated with a mixture of 95% $O_2$ and 5% $CO_2$. Changes in their tension were recorded via isometric transducers connected to a data acquisition system. Results : PYL relaxed the contraction of aortic rings induced by phenylephrine (PE, 1 ${\mu}M$) or KCl (60 mM) in a concentration dependent manner. However, the vasorelaxant effects of PYL on endothelium-denuded aortic rings were lower than endothelium-intact aortic rings. And the vasorelaxant effects of PYL on endothelium-intact aortic rings were reduced by pre-treatment with $N{\omega}$-Nitro-L-arginine methyl ester (10 ${\mu}M$), methylene blue (10 ${\mu}M$), 1-H-[1,2,4]-oxadiazolo-[4,3-${\alpha}$]-quinoxalin-1-one (10 ${\mu}M$), tetraethylammonium (5 mM). In addition, PYL inhibited the contraction induced by extracellular $Ca^{2+}$ in endothelium-denuded aortic rings pre-contracted by PE or KCl in $Ca^{2+}$-free K-H solution. Conclusions : These results suggest that PYL exerts its vasorelaxant effects via the activation of Nitric Oxide (NO) formation by means of L-arginine and NO-cGMP pathways and via the blockage of receptor operated calcium channels, voltage dependent calcium channels and calcium-activated potassium channels.

• Physical Therapy Rehabilitation Science
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• 제13권1호
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• pp.53-70
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• 2024

Background: The conventional deadlift is a popular exercise for enhancing trunk, core, and lower extremity strength. However, its use in sports medicine is constrained by concerns of lumbar injuries, despite evidence supporting its safety and rehabilitative benefits. To optimize muscle activation using resistive bands in variable resistance therapy, we explored their feasibility in the deadlift. Design: Comparative experimental design Methods: Surface electromyography recorded muscle activity in the trunk and lower extremities during lifting, with normalization to the isometric Floor Lift using Maximal Voluntary Contraction. Kinematics were measured using inclinometer sensors to track hip and trunk sagittal plane angles. To prevent fatigue, each subject only used one of the three pairs of bands employed in the study. Results: Our study involved 45 healthy subjects (mean age: 30.4 ± 6.3 years) with similar baseline characteristics, except for years of lifting and strength-to-years-of-lifting ratio. Various resistance band groups exhibited significantly higher muscle activity than conventional deadlifts during different phases. The minimal resistance band group had notably higher muscle activity in the trunk, core, and lower extremity muscles, particularly in the end phase. The moderate resistance band group showed increased muscle activity in the mid-and end-phases. The maximum resistance band group demonstrated greater muscle activity in specific muscles during the early phase and overall higher activity in all trunk and lower extremity muscles in the mid and end phases of the deadlift (p<0.05). Conclusion: Our findings provide valuable insights into muscle activation with various resistance bands during deadlift exercise in clinical and gym settings. There appears to be a dose-response relationship between increased resistance bandwidth, external load, myoelectric activation, and range.