• 약학회지
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• 제45권1호
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• pp.85-92
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• 2001

Nitric oxide is a tonically produced vasodilator that maintains blood pressure in the normal animal. The chronic inhibition of nitric oxide synthase (NOS) elicits the hypertension in rats. However, the mechanism of hypertension induced by chronic inhibition of NOS is not clear. Thus, to clarify the mechanism of the occurance of hypertension, the changes in $\alpha$-adrenergic systems in rats treated with NOS inhibitors for 21 days were examined. Chronic administration of L-NAME significantly increased in the basal blood pressure, but chronic administration of 7-nitroindazole did not. Phenylephrine and G-protein stimulator elicited the more potent contraction in the aorta of the L-NAME-induced hypertensive rats. However when the contractile responses by phenylephrine and G-protein stimulator were calculated the proportion to the contraction by 25 mM KCL, there was no difference between the vehicle-treated rats and the L-NAME-treated rats. The density of $\alpha$-adrenergic receptors in aortic tissue was not changed by the chronic inhibition of NOS. These results suggest that hypertension induced by chronic inhibition of NOS is due to the inhibition of eNOS and the increased responses to the adrenergic drugs are due to the changes of the intracellular contactile mechanism of aortic tissue rather than the changes of receptor density.

• 약학회지
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• 제53권3호
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• pp.156-160
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• 2009

The present study was undertaken to determine whether transgelin participates in the regulation of vascular smooth muscle contraction and, if so, to investigate the mechanism. By PCR homology cloning, the cDNA sequence of ferret transgelin was determined and phosphorothioate antisense and random oligonucleotides were synthesized and introduced into strips of ferret aorta by a chemical loading procedure. Treatment of ferret aorta with transgelin antisense oligonucleotides resulted in a significant decrease in protein levels of transgelin to sham- or random sequence-loaded muscles, but no change in the protein levels of actin. Contraction in response to a phorbol ester was significantly decreased in antisense-treated muscles compared to sham- or random sequence-loaded controls. Neither basal intrinsic tone nor the contraction in response to phenylephrine was significantly affected by the antisense treatment. The data indicate that transgelin plays a significant role in the regulation of contraction and suggest that in a tonically active smooth muscle transgelin may function as a signalling protein to facilitate PKC or ERK-dependent signalling rather than thick filament regulation including $Ca^{2+}$ or calmodulin dependent regulation of myosin light chain kinase.

• The Korean Journal of Physiology
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• 제20권2호
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• pp.175-183
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• 1986

Since it was proposed that vanadate may be an ‘ideal endogenous regulator of the $Na^+,\;K^+-ATPase$ activity (Cantley et at, 1979), vanadate has been a subject of intensive research and a variety of its physiological effects have been described (Nechay, 1984). In isolated guinea pig heart muscle vanadate shows a positive inotropic effect on ventricular muscle, while it induces a negative inotropic effect on atrial muscle. But its underlying mechanism has not been elucidated so far. Therefore, in this study the flux rates of calcium ion into and from guinea pig heart muscle were measured to throw some light on the underlying mechanism, because those rates have been known to be closely related to the cardiac contractility and the results are summarized as follows: 1) Calcium efflux rates from the intracellular $Ca^{++}$ pool (compartment 4) of both guinea pig left atrium and right ventricle were significantly reduced by vanadate and their pool sizes were significantly increased by vanadate. 2) The magnitude of calcium influx into left atrium was reduced by vanadate, While the magnitude of calcium influx into right ventricle was not affected by vanadate. From these results, it may be concluded that the positive inotropic effect of vanadate on the ventricular muscle was due to a reduced efflux rate of calcium ion and its negative inotropic effect on atrial muscle was resulted from a reduced influx of calcium ion.

• The Korean Journal of Physiology
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• 제20권2호
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• pp.199-208
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• 1986

The effects of $Mg^{++}$ upon the spontaneous contraction activated by 1 IU/l oxytocin were studied in the isolated rat uterine muscle. Longitudinal muscle strips u·ere prepared from the rat uteri at the estrous stage. All experiments were performed in tris-buffered Tyrode solution which was aerated with 100% $O_2$ and kept at $35^{\circ}C$. The results obtained were as follows: 1) In the uterine strips contracting spontaneously, as $Mg^{++}$ concentration increased in the Tyrode solution the amplitude of peak tension decreased in all the experimental solutions containing the various concentrations of $Ca^{++}\;(0.5{\sim}4 mM)$. And the amplitude of peak tension increased in inverse proportion to the $[Mg^{++}]/[Ca^{++}]\; ratio$. It is suggested that the tension-lowering effect of $Mg^{++}$ would be developed through decreasing intracellular ionized free calcium ion concentration by uncertain mechanism. 2) The frequency of the uterine contraction activated by oxytocin increased as the $[Mg^{++}]/[Ca^{++}]\;ratio$ ratio increased up to 1/2, but the frequency decreased above this ratio. It is speculated that $Mg^{++}$ would influence the excitability control action of $Ca^{++}$.

• 한국생물물리학회:학술대회논문집
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• 한국생물물리학회 2003년도 정기총회 및 학술발표회
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• pp.52-52
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• 2003

Junctate is a newly identified integral ER/SR membrane $Ca^{2+}$ binding protein, which is an alternative splicing form of the same gene generating aspartyl $\square$-hydroxylase and junctin. To elucidate the functional role of junctate in heart, transgenic (TG) mice overexpressing mouse cardiac junctate-1 under the control of mouse $\square$$^{~}$ myosin heavy chain promoter were generated. Overexpression of junctate in mouse heart resulted in cardiac hypertrophy, increased fibrosis, bradycardia, arrhythmias and impaired contractility. Overexpression of junctate also led to down-regulation of SERCA2, calsequestrin, calreticulin and RyR, but to up-regulation of NCX and PMCA. The SR $Ca^{2+}$ content decreased and the L-type $Ca^{2+}$ current density and the action potential durations increased in TG cardiomyocytes, which could be the cause for the bradycardia in TG heart. The present work has provided an important example of pathogenesis leading to cardiac hypertrophy and arrhythmia, which was caused by impaired $Ca^{2+}$ handling by overexpression of junctate in heart.n heart.

• Investigative Magnetic Resonance Imaging
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• 제20권2호
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• pp.132-135
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• 2016

We report the case of a 43-year-old male with both giant left atrial appendage (LAA) aneurysm and drug-refractory atrial fibrillation (AF). The patient was treated with percutaneous electrical isolation of cardiac arrhythmogenic substrate, and has been free of AF symptom over one year. Although the surgical resection of giant LAA aneurysm is mostly used to prevent systemic thromboembolism, we have performed follow-up of the giant LAA aneurysm using cardiac magnetic resonance (CMR) imaging and transesophageal echocardiography (TEE) after the successful catheter ablation of refractory AF. At one-year follow-up CMR, the giant LAA aneurysm showed remarkable enlargement as well as decreased contractility. Additionally, one-year follow-up TEE showed spontaneous echo contrast as an indicator of blood stasis in the giant LAA aneurysm. Those findings of giant LAA aneurysm suggest that the risk of thromboembolism may be high despite termination of AF.

• Clinical and Experimental Reproductive Medicine
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• 제15권2호
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• pp.93-102
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• 1988

These studies were undertaken to examine the relationship between tamoxifen and sex steroid hormones in rat uterine morphology and the effect of tamoxifen on sex steroid hormone levels, implantation and myometrial contraction. The results obtained were as follows : 1) The increase in height of the luminal epithelium caused by tamoxifen treatment was blocked by progesterone. The increase in height of luminal epithelium caused by $estradiol-17{\beta}$ treatment was blocked by tamoxifen. 2) When a single dose of tamoxifen(10, 20, $40{\mu}g$) was given on Day 2 of pregnancy, implantation was prevented. Plasma $estradiol-17{\beta}$ level fell in a dose-dependent manner but plasma progesterone level was constant. 3) In vitro, tamoxifen decreased rat uterine contractility in a dose-dependent manner.

• 약학회지
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• 제27권2호
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• pp.155-161
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• 1983

The rates of deterioration of contractile forces of isolated hearts from ginseng component treated rats were determined. Rat papillary muscles were also used to study the influence of ginseng on the mechanical performance of heart. Rats weighing 200-300g were administered orally with ginseng ethanol extract (100mg/kg/day), ginseng total saponin (50mg/kg/day) and ginsenoside Rbl (5mg/kg/ day) for a week respectively. The isolated hearts from rats were perfused with Krebs-Henseleit solution by Langendorff perfusion apparatus. The force-velocity relation was clearly seen with the load-generator equipped isotonic shortening recording apparatus. The control group was only able to maintain 60% of their initial contractile forces after 120 minutes of perfusion, whereas ginseng ethanol extract treated group was able to sustain nearly their initial strength even after 120 minutes of perfusion. The similar effects were seen in the hearts treated with total ginseng saponin and ginsenoside Rb$_{1}$. Ginseng ethanol extract did alter mechanical performance of rat ventricular myocardium. It increased both maximum velocity(Vmax) of isotonic shortening and isometric force (P$_{0}$) and showed increased velocity of shortening significantly (P<0,05) at any one afterload.d.

• Mycobiology
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• 제48권2호
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• pp.153-156
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• 2020

Calvatia nipponica, a puffball mushroom (Agaricaceae), is thought to be an aphrodisiac, as this mushroom is traditionally known to improve sexual function in males. As part of the systematic study to determine the bioactive secondary metabolites from C. nipponica responsible for aphrodisiac effects, chemical analysis of methanol (MeOH) extracts of the fruiting bodies of C. nipponica resulted in the isolation of two major compounds: N,N-dimethyl-anthranilic acid (1) and (7Z,10Z)-7,10-octadecadienoic acid methyl ester (2). Compounds 1 and 2 were evaluated for cumulative dose-dependent relaxation responses to precontracted penile corpus smooth muscle (PCCSM). Results show that compounds 1 and 2 exhibited a maximum relaxation effect of 20.33 ± 2.18% and 24.63 ± 3.60%, respectively. These findings indicate that compounds 1 and 2, major components of C. nipponica, could potentially be used to treat erectile dysfunction, functioning as natural aphrodisiacs.

• Molecules and Cells
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• 제22권3호
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• pp.275-284
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• 2006

The molecular components that generate and maintain circadian rhythms of physiology and behavior in mammals are present both in the brain (suprachiasmatic nucleus; SCN) and in peripheral tissues. Examination of mice with targeted disruptions of either mPer1 or mPer2 has shown that these two genes have key roles in the SCN circadian clock. Here we show that loss of the clock gene mPer2 affects forced locomotor performance in mice without altering muscle contractility. A proteomic analysis revealed that the anterior tibialis muscles of the mPer2 knockout mice had higher levels of glycolytic enzymes such as triose phosphate isomerase and enolase than those of either the wild type or mPer1 knockout mice. In addition, the level of expression of HSP90 in the mPer2 mutant mice was also significantly higher than in wildtype mice. These results suggest that the reduced locomotor endurance of the mPer2 knockout mice reflects a greater dependence on anaerobic metabolism under stress conditions, and that the two canonical clock genes, mPer1 and mPer2, play distinct roles in the physiology of skeletal muscle.