• 대한약리학회지
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• 제12권2호
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• pp.13-19
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• 1976

A fluid extract of Zizyphi Semen was employed in this experiment. The cardiac effects of Zizyphi Semen were examined on isolated rabbits atria and heart in situ of anesthetized cats and rabbits. The adrenergic blocking activity and refractory period of cardiac muscle were measured after administration of this drug. In rabbits and cats the antiarrhythmic action of Zizyphi Semen on atrial and ventricular arrhythmias produced by epinephrine or ouabain was examined. The results were following: 1. Zizyphi Semen produced a decrease in rate and contractile amplitude of the isolated rabbit atria and had a week blocking effect on epinephrine acceleration of atrial movement. 2. Zizyphi Semen effectively abolished the spontaneous arrhythmia occurring in the isolated rabbit atria ana the atrial arrhythmia induced by ouabain. 3. Zizyphi Semen produced a marked prolongation of the refractory period in isolated atrial muscle of rabbit. 4. Zizyphi Semen prevented the induction of ventricular arrhythmia arising from excessive dose of epinephrine in anesthetized rabbits and cats. 5. With regard to the ventricular arrhythmia induced by a continuous infusion of ouabain, Zizyphi Semen exerted suppressive effect and produced a marked prolongation of cardiac arrest time in anesthetized rabbits and cats. From the above results, it may be concluded that Zizyphi Semen is effective against atrial and ventricular arrhythmias. The antiarrhythmic effect of this drug may be the result of direct myocardial depressive and partially adrenergic beta receptor blocking activities including prolongation of the refractory period of cardiac muscle.

• 약학회지
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• 제32권2호
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• pp.129-136
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• 1988

Effects of the selective alpha-adrenoceptor agonists, clonidine, oxymetazoline and phenylephrine, on heart rate and contractile force were investigated in the isolated frog atria and it was attempted to examine the influence of adrenoceptor antagonist upon those. Clonidine produced dose-dependent negative chronotropic and positive inotropic effects. The negative chronotropic effect was significantly attenuated in the presence of prazosin and yohimbine but not propranolol. The positive inotropic effect was significantly attenuated by prazosin, yohimbine and propranolol. Oxymetazoline produced dose-dependent negative chronotropic and inotropic effects. The negative chronotropic effect was significantly attenuated in the presence of prazosin, which was partially augmented by yohimbine but was not affected by propranolol. The negative inotropic effect was not affected by propranolol but it was partially augmented by yohimbine and was partially attenuated by prazosin. Phenylephrine produced dose-dependent positive chronotropic and inotropic effects. The positive chronotropic and inotropic effect were significantly attenuated in the presence of propranolol but were not affected by prazosin and yohimbine. These results suggest that the negative chronotropic effect by clonidine and oxymetazoline is mediated by alpha-adrenoceptors, the positive chronotropic and inotropic effects by phenylephrine are mediated by beta-adrenoceptors, and alpha-adrenoceptors mediated the inhibitory chronotropic responses exists in the isolated frog atria.

• 대한약리학회지
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• 제31권1호
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• pp.53-61
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• 1995

Lidocaine의 심근 수축력 억제 기전이 적출 심장에서 내인성 기질의 사용과 관련이 있는가를 규명하기 위하여, 심장의 phosphofructokinase (PFK)에 대한 강력한 억제 작용을 나타내는 citracte와 bicarbonate-free medium을 이용하여 쥐의 적출 심방 수축성에 대한 lidocaine의 영향을 연구하여 다음과 같은 실험 결과를 얻었다. Citrate와 bicarbonate-free medium은 쥐의 적출 심방의 수축력을 현저히 저하시켰다. Pyruvate나 acetate는 citracte와 bicarbonate-free medium에서 저하된 심방 수축력을 현저히 증가시키는 반면, fructose는 수축력을 증가시키지 못했다. 이 결과는 citrate와 bicarbonate-free medium이 Embden-Meyerhof pathway의 일부, 즉 PFK step을 억제함을 시사한다. 외인성 기질이 없을때 citrate와 bicarbonate-free medium은 기질 제거 용액에서 심방 수축력을 현저히 감소시키며, acetate에 의해 수축력이 회복되었다. 이는 PFK step 이전 단계의 내인성 기질 (glycogen)이 citrated에 의해 억제됨을 시사한다. Lidocaine은 citrate에 의해 억제된 수축력을 더욱 감소시켰다. 이 결과는 lidocaine에 의한 심방 수축력 억제가 PFK step 이후 단계의 내인성 기질 억제에 의한 것임을 시사한다. 이상의 결과로 보아 lidocaine의 적출 심방에 대한 수축력 억제 작용은 두가지 (또는 그 이상)의 기전에 의한 것으로 사료된다: 하나는 PFK step 전단계의 해당과정의 억제기전이고 또 다른 기전은 PFK step 이후의 내인성 기질(들)의 억제인 것으로 사료된다.

• 대한약리학회지
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• 제26권2호
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• pp.121-126
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• 1990

Lidocaine의 심근 수축력 억제작용의 기전을 규명하기 위한 일환으로 정상 Krebs-Ringer bicarbonate glucose용액에서 각종 대사기질이 lidocaine 억제심방과 정상심방의 수축력에 미치는 영향, 그리고 glucose 제거용액에서 lidocaine의 심방 수축력에 대한 영향을 검토하여 다음과 같은 결과를 얻었다. 1. Pyruvate(5mM), acetate(5mM), fructose(30mM)는 lidocaine에 의해 감소된 심방 수축력을 현저히 증가시켰으나, 정상심장에는 별 영향이 없었다. 2. Glucose(20mM)는 lidocaine억제심방의 수축력을 증가시키지 못하였으나 정상심방의 수축력을 현저히 증가시켰다. 3. Glucose 제거용액에서 lidocaine은 정상용액에서보다 심방 수축력을 현저히 더 감소시켰다. 이상의 결과로 보아 lidocaine은 적출심장에서 외인성 glucose를 제거시, 심장 glycogen의 이용을 glucose phosphate isomerase 단계 혹은 glycogen이 glucose-6-phosphates로 전환되는 단계를 억제한다는 것을 시사하고 있다.

• The Korean Journal of Physiology and Pharmacology
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• 제25권2호
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• pp.159-166
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• 2021

Nicotinamide adenine dinucleotide phosphate oxidases (NOXs) are the major enzymatic source of reactive oxygen species (ROS). NOX2 and NOX4 are expressed in the heart but its role in hypoxia-induced atrial natriuretic peptide (ANP) secretion is unclear. This study investigated the effect of NOX on ANP secretion induced by hypoxia in isolated beating rat atria. The results showed that hypoxia significantly upregulated NOX4 but not NOX2 expression, which was completely abolished by endothelin-1 (ET-1) type A and B receptor antagonists BQ123 (0.3 μM) and BQ788 (0.3 μM). ET-1-upregulated NOX4 expression was also blocked by antagonists of secreted phospholipase A2 (sPLA2; varespladib, 5.0 μM) and cytosolic PLA2 (cPLA2; CAY10650, 120.0 nM), and ET-1-induced cPLA2 expression was inhibited by varespladib under normoxia. Moreover, hypoxia-increased ANP secretion was evidently attenuated by the NOX4 antagonist GLX351322 (35.0 μM) and inhibitor of ROS N-Acetyl-D-cysteine (NAC, 15.0 mM), and hypoxia-increased production of ROS was blocked by GLX351322. In addition, hypoxia markedly upregulated Src expression, which was blocked by ET receptors, NOX4, and ROS antagonists. ET-1-increased Src expression was also inhibited by NAC under normoxia. Furthermore, hypoxia-activated extracellular signal-regulated kinase 1/2 (ERK1/2) and protein kinase B (Akt) were completely abolished by Src inhibitor 1 (1.0 μM), and hypoxia-increased GATA4 was inhibited by the ERK1/2 and Akt antagonists PD98059 (10.0 μM) and LY294002 (10.0 μM), respectively. However, hypoxia-induced ANP secretion was substantially inhibited by Src inhibitor. These results indicate that NOX4/Src modulated by ET-1 regulates ANP secretion by activating ERK1/2 and Akt/GATA4 signaling in isolated beating rat hypoxic atria.

• The Korean Journal of Physiology and Pharmacology
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• 제26권6호
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• pp.469-478
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• 2022

WNT signaling plays an important role in cardiac development, but abnormal activity is often associated with cardiac hypertrophy, myocardial infarction, remodeling, and heart failure. The effect of WNT signaling on regulation of atrial natriuretic peptide (ANP) secretion is unclear. Therefore, the purpose of this study was to investigate the effect of Wnt agonist 1 (Wnta1) on ANP secretion and mechanical dynamics in beating rat atria. Wnta1 treatment significantly increased atrial ANP secretion and pulse pressure; these effects were blocked by U73122, an antagonist of phospholipase C. U73122 also abolished the effects of Wnta1-mediated upregulation of protein kinase C (PKC) β and γ expression, and the PKC antagonist Go 6983 eliminated Wnta1-induced secretion of ANP. In addition, Wnta1 upregulated levels of phospho-transforming growth factor-β activated kinase 1 (p-TAK1), TAK1 banding 1 (TAB1) and phospho-activating transcription factor 2 (p-ATF2); these effects were blocked by both U73122 and Go 6983. Wnta1-induced ATF2 was abrogated by inhibition of TAK1. Furthermore, Wnta1 upregulated the expression of T cell factor (TCF) 3, TCF4, and lymphoid enhancer factor 1 (LEF1), and these effects were blocked by U73122 and Go 6983. Tak1 inhibition abolished the Wnta1-induced expression of TCF3, TCF4, and LEF1 and Wnta1-mediated ANP secretion and changes in mechanical dynamics. These results suggest that Wnta1 increased the secretion of ANP and mechanical dynamics in beating rat atria by activation of PKC-TAK1-ATF2-TCF3/LEF1 and TCF4/LEF1 signaling mainly via the WNT/Ca²⁺ pathway. It is also suggested that WNT-ANP signaling is implicated in cardiac physiology and pathophysiology.

• Investigative Magnetic Resonance Imaging
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• 제19권4호
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• pp.205-211
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• 2015

The human heart is a complex organ in which many complicated congenital defects may happen and some of them require surgical intervention. Due to the vast complexity of varied anatomical presentations, establishing an accurate and consistent nomenclature system is utmost important to facilitate effective communication among pediatric cardiologists, cardiothoracic surgeons and radiologists. The Van Praagh segmental approach to the complex congenital heart disease (CHD) was developed in the 1960s and has been used widely as the language for describing complex anatomy of CHD over the decades. It utilizes a systematic and sequential method to describe the cardiac segments and connections which in turn allows accurate, comprehensive and unambiguous description of CHD. It can also be applied to multiple imaging modalities such as echocardiogram, cardiac CT and MRI. The Van Praagh notation demonstrates a group of three letters, with each letter representative for a key embryologic region of cardiac anatomy: the atria, ventricles and great vessels. By using a 3-steps approach, we can evaluate complex CHD precisely and have no difficulties in communicating with other medial colleague. This pictorial essay revisits the logical steps of segmental approach, followed by a pictorial illustration of its application.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1995년도 춘계학술대회
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• pp.88-88
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• 1995

Tetrahydroisoquinoline (THI) compounds have various pharmacological actions in the cardiovascular system. Recently, we have synthesized 1-${\alpha}$-naphthylmethyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline, YS 49. In the present study, we evaluated the effect of YS-49 on positive inotropic and chronotropic action using isolated rat heart and on blood pressure and heart rate using anesthesized rabbit. Vasodilating action was also assessed in isolated rat thoracic aorta. YS 49, concentration-dependently relaxed rat aorta precontracted with phenylephrine (PE, 0.3 ${\mu}$M) and high potassium (high K$\^$+/, 65.4 mM). The 50% inhibitory concentration (IC$\sub$50/) of YS 49 in PE-induced and high K$\^$+/-induded contraction was 5.36 ${\mu}$M and 2.52 ${\mu}$M, respectively. In isolated rat atria, YS 49 increased both heart rate and force, and in anesthesized rabbit it decreased blood pressure but increased heart rate. In addition, to know the mechanism of action of the compound, propranolol, nonselective ${\beta}$-antagonist, and phentolamine, ${\alpha}$-blocker, were used. Furthermore, a comparison with the effect of higenamine, trimetoquinol on the vasodilating action in rat thoracic aorta was also made. The action of YS 49 was inhibited by the presence of propranolo, not pentolamine. These results indicate that cardiotonic and vasodilatory action of YS 49 is attributable, at least in part, for ${\beta}$-receptor stimulation.

• 한국동물학회지
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• 제7권2호
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• pp.48-52
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• 1964

1. The auther studied the interrelationship between the sensibility of heart of fishes to neuro-hormones (epinephrine, norepinephrine and acetylcholinie) and 5-hydroxytryptamine and the differentiation of nervous system in the heart . Attempts were also made to develop the similarity and systematic relationship of inter-genus and inter-species. 2. Judging from the reactions to neurohormones, it is considered that inter-genus of locah (Misgurnus mizolepis GNTHER) and eel (Anguilla japonic TEMMINEK & SCHJEGEL) are more closely related than that of Crucian (Carassius carassius L. ). 3. As the sensibility of locach to 50 jhdroxytryptamine is more sensitive over 10, 000 times than that of a Mollusca, Meretrix lusoria RODING, it is very excellent material for the bioassay of 5-jydroxytryptamine.

• The Korean Journal of Physiology
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• 제8권2호
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• pp.33-44
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• 1974

The electrocardiogram of frogs were obtained in winter (January), spring (April), summer (July) and autumn (September and November). Electrocardiograms were recorded applying electrodes to the atria, ventricle and apex of the heart by unipolar or bipolar leads. V wave was recorded prior to P wave, for the presence of the sinus venosus which controls the automaticity of the frog heart, in four seasons. Regardless of the leads or the position of the electrodes P wave was diphasic and wide. According to the rise of temperature the rate of heart beat was increased, and V-P and P-R interval were shortened. Two regression line between R-R interval and both V-P interval and P-R interval were drawn. These were calculated as V-P interval=1 0.276R-R $interva1+0.067{\pm}0.15$ (sec.) and P-R interval=0.179R-R $interva1+0.155{\pm}0.1$ (sec). From these calculation the larger gradient of V-P interval than P-R interval was suggestive that the heart rate is more dependent on the changes of V-P interval than that of P-R interval. Changes of the heart rate were also measured in four seasons and artificial temperatures. Two regression lines between the heart rate (H.H.) and both seasonal temperature (T) and artificial temperature, were drawn. These two lines were calculated as H.R.=20+3.71 (T-10) and H.R.=32+1.425 T respectively. From two gradients of the above equations it is considered that the changes of the heart rate in artificial temperature were milder than that in seasonal temperature. The number of RBC and WBC of frogs were measured in four seasons and a tendency of the changes was observed according to the seasonal variation.