• The Korean Journal of Physiology
• /
• 제18권2호
• /
• pp.139-150
• /
• 1984

Vanadate의 회장 평활근에 대한 수축작용이 Na-K-ATPase를 억제하기 때문인지를 구명하기 위하여 Na-K-ATPase를 억제하는 ouabain과의 작용의 차이를 관찰한 결과 다음과 같은 결론을 얻었다. 1) Ouabain에 의해 나타나는 수축은 2중 peak를 나타내었으나 vanadate 의해서는 단일 Peak만을 보였다. 2) Ouabain에 의한 수축은 atropine$(2{\times]10^{-6}M)$에 의해 강력하게 억제되었으나 vanadate의 작용은 영향을 받지 않았다. 3) Ouabain에 의한 수축은 vanadate에 비해 외부의 $Ca^{++}4농도 및 Ca-길항제에 대해 민감하게 영향을 받았다. 4) 용액내 $Na^+$이 없을때 혹은 고농도의 $K^+$존재하에서 ouabain에 의한 수축반응은 거의 나타나지 않았으나 vanadate에 의한 수축은 영향을 받지 않았다. 5) Vanadate에 의한 수축은 ouabain 존재시에 더욱 증가되었다. 6) 3시간동안 incubation한 결과 vanadate는 ouabain과 달리 세포내 $Na^+$의 농도에 영향을 미치지 못하였다. 이상의 결과로 보아 ouabain과 vanadate는 서로 다른 기전에 의해 회장 평활근에서 수축반응을 유발시키는 것으로 추측된다.

• 대한약리학회지
• /
• 제23권2호
• /
• pp.133-141
• /
• 1987

Acetylcholine및 oxytocin에 의하여 야기되는 흰쥐의 적출자궁수축을 $Ca^{2+}$ 길항제의 일종인 verapamil및 tetracaine 존재하에서 acetylcholine및 oxytocin에 의한 자궁수축곡선을 4개의 요소 (trough tension, T: peak tension, P; contraction frequency, F: duration, D)로 나누어 비교분석하여 다음과 같은 결과를 얻었다. Verapamil $(0.25\;{\mu}M)$은 자발수축을 억제시켰으나 tetracaine$(42\;{\mu}M)$은 자발수축을 억제시키지 못하였다. 이들 길항제의 존재하에서 acetylcholine및 oxytocin에 의하여 야기되는 자궁수축의 각 구성요소에 변화를 관찰하였다. 즉 acetylcholine에 의한 수축에서 verapamil은 P와 D를 감소시켰고 tetracaine은 F를 감소시키고 D를 증가시켰다. oxytocin에 의한 수축에서 verapamil은 P와 D를 감소시켰으나 tetracaine은 oxytocin농도에 따라 차이가 있었는데, 저농도의 oxytocin에 의한 수축에서는 F를 감소시키고 D를 증가시켰으나 고농도의 oxytocin에 의한 수축에서 는 F와 D에는 영향을 주지 않고 P만 감소시켰다. 이상의 결과로 미루어 acetylcholine및 oxytocin에 의하여 야기되는 수축곡선은 시각적으로 큰 차이가 없었으나 작용기전이 다른 $Ca^{2+}$ 길항제에 의하여 acetylcholine및 oxytocin의 수축의 구성요소에 다르게 영향을 미칠 수 있었다는 것은 수축곡선의 구성요소의 변화를 면밀히 검토하면 자궁수축제의 수축작용기전이 다름을 예측할 수 있을 뿐만 아니라 수축억제제에 의한 억제 기전의 차이점도 예측할 수 있을 것으로 생각되어 진다.

• The Korean Journal of Physiology and Pharmacology
• /
• 제11권5호
• /
• pp.207-213
• /
• 2007

This study was designed to characterize ureteral smooth muscle motility and also to study the effect of forskolin(FSK) and isoproterenol(ISO) on smooth muscle contractility in murine ureter. High $K^+$(50 mM) produced tonic contraction by $0.17{\pm}0.06mN$(n=19). Neuropeptide and neurotransmitters such as serotonin($5{\mu}M$), histamine($20{\mu}M$), and carbarchol(CCh, $10{\sim}50{\mu}M$) did not produce significant contraction. However, CCh($50{\mu}M$) produced slow phasic contraction in the presence of 25 mM $K^+$. Cyclopiazonic acid(CPA, $10{\mu}M$), SR $Ca^{2+}$-ATPase blocker, produced tonic contraction(0.07 mN). Meanwhile, inhibition of mitochondria by protonophore carbnylcyanide m-chlorophenylhydrazone(CCCP) also produced weak tonic contraction(0.01 mN). The possible involvement of $K^+$ channels was also pursued. Tetraethyl ammonium chloride(TEA, 10 mM), glibenclamide($10{\mu}M$) and quinidine($20{\mu}M$) which are known to block $Ca^{2+}$-activated $K^+$ channels($K_{Ca}$ channel), ATP-sensitive $K^+$ channels($K_{ATP}$) and nonselective $K^+$ channel, respectively, did not elicit any significant effect. However, $Ba^{2+}$($1{\sim}2mM$), blocker of inward rectifier $K^+$ channels($K_{IR}$ channel), produced phasic contraction in a reversible manner, which was blocked by $1{\mu}M$ nicardipine, a blocker of dehydropyridine-sensitive voltage-dependent L-type $Ca^{2+}$ channels($VDCC_L$) in smooth muscle membrane. This $Ba^{2+}$-induced phasic contraction was significantly enhanced by $10{\mu}M$ cyclopiazonic acid(CPA) in the frequency and amplitude. Finally, regulation of $Ba^{2+}$-induced contraction was studied by FSK and ISO which are known as adenylyl cyclase activator and $\beta$-adrenergic receptor agonist, respectively. These drugs significantly suppressed the frequency and amplitude of $Ba^{2+}$-induced contraction(p<0.05). These results suggest that $Ba^{2+}$ produces phasic contraction in murine ureteral smooth muscle which can be regulated by FSK and $\beta$-adrenergic stimulation.

• 대한물리치료과학회지
• /
• 제2권3호
• /
• pp.587-598
• /
• 1995

The purpose of this study was to test the microcurrent electrical neuromuscular stimulation on muscle soreness, serum creatine kinase levels and force deficits evident following a high-intensity eccentric exercise bout. 10 volunteer male subjects were randomly assigned to a treatment group or to a control group. Exercise consisted of high-intensity eccentric contractions of the elbow flexors. Resistance was reduced as subjects fatigued, until they reached exhaustion. Muscle soreness rating was determined using a visual analog scale. Serum creatine kinase levels were analyzed using a blood sample. Force deficits were determined by measures of maximal voluntary isometric contraction at $90^{\circ}$ of elbow flexion on a Orthotron II dynamometer. Muscle soreness rating, serum creatine kinase levels and maximal voluntary isometric contraction were determined at the before exercise and again at 24 and 48 hours postexericse. Treatments were applied immediately following exercise. The control group subjects rested following their exercise bout. Statistical analysis showed significant increases in muscle soreness rating and significant decreases in maximal voluntary isometric contraction when the before exercise was compared with 24 and 48 hour measures(p<0.01). No significant effects were observed between groups in muscle soreness rating and maximal voluntary isometric contraction(p>0.05). Highly significants differences in serum creatine kinase levels were found using on Analysis of variance(ANOVA) repeated measures between groups for each time cycles(p<0.001). This modality may have benefits when used early stage in the muscle damage.

• Journal of Ginseng Research
• /
• 제18권2호
• /
• pp.95-101
• /
• 1994

Saponin of Panax ginseng (C.A. Meyer) is composed of Protopanaxatriol (PT) and Protopanaxa- diol (PD). We investigated the effects of PT and PD on the contractility and $^{45}Ca$ uptake in the pig coronary artery. Isometric tension in the helical strips and $^{45}Ca$ uptake in the ring strips were measured in the presence or absence of PT and PD. PT and PD did not affect the high K+ (40 mM)-induced contraction but relaxed the ACh-induced contraction in a dose4ependent manner (1~10 mg/dl). The vasorelaxing effect of PT on the ACh-induced contraction was more potent than that of PD. Those relaxations were partially suppressed by the rubbing of endothelium removal. ACh-induced contraction in the $Ca^{2+}$-free Tyrode's solution was suppressed by the pretreatment of PT or PD. Following the depletion of ACh-sensitive intracellular $Ca^{2+}$ pool, ACh-induced contraction was suppressed by the pratreatment of PT or PD. With the pretreatment of PT or PD, $^{45}Ca$ uptake by high K+ (43 mM) was not changed but that by ACh was suppressed in the pig coronary artery. From the above results, we suggested that the vasorelaxing effect of PT and PD of Panax ginseng was due to inhibition of intracellular $Ca^{2+}$ release, inhibition of $Ca^{2+}$ uptake via receptor-operated $Ca^{2+}$ channels and in part a release of vasorelaxing factor from endothelium in pig coronary artery.

• 대한금속재료학회지
• /
• 제50권10호
• /
• pp.703-710
• /
• 2012

The effects of the ordering reaction on high temperature mechanical behavior is investigated by tensile tests at $2{\times}10^{-2}/s-3.3{\times}10^{-5}/s$ up to $745^{\circ}C$. The tensile deformed region is examined by differential scanning calorimeter (DSC), TEM, and high resolution neutron diffraction (HRPD). The results showed that a plateau of tensile strength appeared at $150-500^{\circ}C$ whereas the elongation minimum occurred at about $600^{\circ}C$. This suggests that the occurrence of a plateau does not cause the elongation minimum. The temperature of the elongation minimum decreases with the strain rate. HRPD results show a lattice contraction in the tensile deformed specimen at the temperature of the plateau occurring region. The plateau of tensile strength, the lattice contraction, and the occurrence of serration appeared in the same temperature region.

• The Korean Journal of Physiology and Pharmacology
• /
• 제3권2호
• /
• pp.165-174
• /
• 1999

We explore the question of whether adenosine 5'-triphosphate (ATP) acts as an excitatory neurotransmitter in guinea-pig gastric smooth muscle. In an organ bath system, isometric force of the circular smooth muscle of guinea-pig gastric antrum was measured in the presence of atropine and guanethidine. Under electrical field stimulation (EFS) at high frequencies (＞20 Hz), NO-mediated relaxation during EFS was followed by a strong contraction after the cessation of EFS (a 'rebound-contraction'). Exogenous ATP mimicked the rebound-contraction. A known $P_{2Y}-purinoceptor$ antagonist, reactive blue 2 (RB-2), blocked the rebound-contraction while selective desensitization of $P_{2Y}-purinoceptor$ with ${\alpha},{\beta}-MeATP$ did not affect it. ATP and 2-MeSATP induced smooth muscle contraction, which was effectively blocked by RB-2 and suramin, a nonselective $P_2-purinoceptor$ antagonist. Particularly, in the presence of RB-2, exogenous ATP and 2-MeSATP inhibited spontaneous phasic contractions, suggesting the existence of different populations of purinoceptors. Both the rebound-contraction and the agonist-induced contraction were not inhibited by indomethacin. The rank orders of agonists' potency were 2-MeSATP > ATP ${ge}$ UTP for contraction and ${\alpha},{\beta}-MeATP\;{\ge}\;{\beta},{\gamma}-MeATP$ for inhibition of the phasic contraction, that accord with the commonly accepted rank order of the classical $P_{2Y}-purinoceptor$ subtypes. Electrical activities of smooth muscles were only slightly influenced by ATP and 2-MeSATP, whereas ${\alpha},{\beta}-MeATP$ attenuated slow waves with membrane hyperpolarization. From the above results, it is suggested that ATP acts as an excitatory neurotransmitter, which mediates the rebound-contraction via $P_{2Y}-purinoceptor$ in guinea-pig gastric antrum.

• 과학교육연구지
• /
• 제42권2호
• /
• pp.95-105
• /
• 2018

이 연구의 목적은 생체 모방 기반 융합 학습 모델을 이용하여 골격근의 구조 및 수축 메커니즘에 대한 디지털 교과서를 개발하는 것이다. 골격근의 구조 및 수축 메커니즘 단원은 고등학교 생명과학I에 포함된 내용이다. 융합 학습 모델은 3D 모델링 및 프린팅을 포함하는 3단계의 생체 모방 기반 융합 학습(Exploration-Design-Implementation)으로 설계되었다. 개발된 디지털 교재는 8차시로 구성되어 있는데, 골격근 탐색, 스케치 앱과 3D 모델링을 이용한 골격근 모방 창의적 설계 2개 차시, 3D 프린팅을 이용하여 설계안의 융합적 구현, 근수축의 탐색, 스케치 앱과 3D 모델링을 이용한 근수축 모방 창의적 설계 2개 차시, 3D 프린팅을 이용하여 설계안의 융합적 구현 등으로 구성되었다. 각 차시는 대화 형 및 모바일 학습을 위해 갤러리 위젯, 미디어 위젯, 프레젠테이션 위젯, 스케치 위젯, 클라우드, 설문 위젯 및 평가 위젯의 컨텐츠를 포함하고 있다. 개발 된 디지털 교과서를 고등학생 20 명에게 투입한 결과 학생들의 생명과학 학습에 효과가 긍정적인 것으로 나타났다. 또한 이 연구에서 개발된 생체 모방 기반 융합 학습 디지털 교재는 학생들의 창의적 설계 및 구현 능력의 향상에서 효과적인 학습자료로 평가되었다. 이러한 결과를 볼 때 디지털 교재는 학생들의 흥미와 생명과학에 대한 자기주도적 학습에 유용한 자료임을 보여주었다.

• The Korean Journal of Physiology
• /
• 제28권2호
• /
• pp.169-179
• /
• 1994

The effect of extracellular and intracellular pH on vascular tone and $^{45}Ca$ uptake were investigated in aortic strips and dispersed single aortic smooth muscle cells of spontaneously hypertensive rats (SHR) and aged-matched Wistar-Kyoto rats (WKY). The contraction produced by a change of extracellular pH (pHo) in the range of $6.5{\sim}8.3$ was estimated by comparison with the level of vascular tone at pH 7.4. Contraction was induced below pHo 6.5 in WKY, pHo 7.1 in SHR, and over pHo 8.0 on both strains. The amplitude of contraction induced by high pHo (over pHo 7.7) was similar in SHR and WKY, but that induced by low pHo (below pHo 7.1) in SHR was greater than that in WKY. Either high pHo- or low pHo-induced contractions in WKY and SHR were not induced in the Ca-free Tyrode's solution and were induced by the addition of Ca. $^{45}Ca$ uptake increased progressively as pHo was increased from 6.8 to 8.1 in the single aortic smooth muscle cells of WKY and SHR. $NH_4Cl$ induced a gradually developing contraction in a dose-dependent manner $(5\;mM{\sim}30\;mM)$ and the removal of $NH_4Cl$ induced transient contraction was followed by profound relaxation in the aortic rings of both strains. The contractions induced by $NH_4Cl$ or by the removal of $NH_4Cl$ in SHR were significantly greater than that in WKY. These contractions were not induced in Ca-free Tyrode's solution. $^{45}Ca$ uptake was increased by $NH_4Cl$ (20 mM) and was not changed by the removal of $NH_4Cl$ (20 mM) in the aortic strips of WKY and SHR. As a summary of above results, the vascular tone of SHR was more sensitive to the change pHi and pHo than that of WKY. The contractions induced by change of extracellular or intracellular pH depended on extracellular Ca in the aorta of SHR nnd WKY. However, the Ca uptake was in accord with the changes of contraction but increase in contraction by low pH was not accompanied by an increase in Ca uptake in both strains.

• Archives of Pharmacal Research
• /
• 제27권6호
• /
• pp.646-652
• /
• 2004

The objective of this study was to determine the acute effect of trimetazidine (TMZ) on the pre-fatigue, fatigue and post-fatigue contractile characteristics and tension-frequency relationships of isolated rat diaphragm muscle. Muscle strips were taken from the ventral-costal aspects of the diaphragm muscle of rats killed by decapitation. The muscle strips were suspended in organ baths containing Krebs solution, with a gas mixture of 95% $O_2$ and 5% $CO_2$ at $37^{\circ}C$ and pH 7.35-7.45. After determining the thermoregulation and optimum muscle length the muscles were subjected to direct supramaximal stimulation with 0.05 Hz frequency square pulses for periods of 0.5 msec to obtain control values. After adding $5{\times}10^{-6}{\;}and{\;}5{\times}10^{-5}$ M trimetazidine solution to the respective bath media, the contractile parameters of the muscles were recorded. The contractile parameters were also recorded for both the trimetazidine and tri-metazidine-free media after application of the high frequency fatigue protocols. Later, the tension-frequency relationship was determined by applying stimulating pulses of 10, 20, 50 and 100 Hz to the muscle strips. Whilst the twitch tension obtained from the $5{\times}10^{-6}{\;}and{\;}5{\times}10^{-5}$ M trimetazidine media showed numerical increases compared to that of the controls, these were not statistically significant (p>0.05). The contraction time exhibited a dose dependent increase (p<0.001), whilst the contraction and relaxation rates did not differ significantly. The isometric contraction forces obtained with the different stimulating frequencies showed a significant increase in the tetanic contraction only at 100 Hz (p<0.05). A comparison of the pre- and post-fatigue twitch tensions in the trimetazidine media showed the post- fatigue twitch tensions to be significantly higher than those of the pre-fatigue contraction forces (p<0.05). In the $5{\times}10^{-6}{\;}and{\;}5{\times}10^{-5}$ M trimetazidine media the increases in the post-fatigue contraction force were 22 and 30%, respectively. These results demonstrated that in isolated rat diaphragm muscle, TMZ significantly limited the mechanical performance decrease during fatigue. It is our opinion that trimetazidine contributed to the observed fatigue tolerance by eliminating the factors of fatigue, due to preservation of intracellular calcium homeostasis, provision of the ATP energy levels needed by ATPase dependent pumps and especially by keeping the intracellular pH within cer-tain limits.