• 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.

• Tuberculosis and Respiratory Diseases
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• 제48권2호
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• pp.210-222
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• 2000

한국산 잡견 11마리를 대상으로 자가 혈병을 이용한 급성 폐색전증을 만들고 ET 수용체 길항제를 투여하여 다음과 같은 결과를 얻었다. 1. 혈병 투여후 폐동맥압은 상승하였고 심박출량은 감소하였으며 페혈관 저항은 증가하였다. 동맥혈 산소분압과 혼합 정맥혈의 산소 분압이 감소하였고 사강호흡이 증가하였고 생리적 단락이 증가하였으나 전신혈압은 변동이 없었다. 모든 측정치는 수용체 길항제 투여군과 대조군간에 차이를 보이지 않았다. 2. ET-1 수용체 길항제 투여후 전신혈압, 동맥 및 혼합정맥혈산소 분압, 동정맥 단락, 및 사강호흡의 정도는 두군간에 차이를 보이지 않았으나, 폐동맥압, 심박출량, 폐혈관 저항은 길항제 투여 30분후부터 수용체 길항제 투여군과 대조군간에 차이를 보이기 시작하여 210분후까지 지속되었다. 3. ET-1의 농도는 색전전(Baseline)에 비하여 색전후 동맥혈, 혼합정맥혈, 및 그 비(동맥혈/혼합정맥혈)가 증가를 보였고, 수용체 길항제 투여후 투여군에서는 대조군에 비해 ET-1의 농도 증가가 의미 있게 높았다. 4. 면역조직화학염색상에서 폐색전증이 유발된 개의 폐혈관 및 폐조직에서 색전을 투여하지 않은 정상 개의 조직에 비해 ET-1의 발현이 증가되었다. 5. Northern blot 상에서 폐색전이 일어난 폐조직의 preproET-1 mRNA 발현은 색전이 일어나지 않은 개의 폐조직에 비하여 증가되었다.

• The Korean Journal of Physiology and Pharmacology
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• 제14권3호
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• pp.145-150
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• 2010

Adenosine (Ado) is an important mediator of the endogenous defense against ischemia-induced injury in the heart. The action of Ado is mediated by activation of G protein-gated inwardly rectifying $K^+$ (GIRK) channels. In turn, GIRK channels are inhibited by reducing phosphatidylinositol 4,5-bisphosphate ($PIP_2$) through Gq protein-coupled receptors (GqPCRs). We previously found that GIRK channels activated by acetylcholine, a muscarinic M2 acetylcholine receptor agonist, are inhibited by GqPCRs in a receptor-specific manner. However, it is not known whether GIRK channels activated by Ado signaling are also regulated by GqPCRs. Presently, this was investigated in mouse atrial myocytes using the patch clamp technique. GIRK channels were activated by $100\;{\mu}M$ Ado. When Ado was repetitively applied at intervals of 5~6 min, the amplitude of second Ado-activated GIRK currents ($I_{K(Ado)}$) was $88.3{\pm}3.7%$ of the first $I_{K(Ado)}$ in the control. Pretreatment of atrial myocytes with phenylephrine, endothelin-1, or bradykinin prior to a second application of Ado reduced the amplitude of the second $I_{K(Ado)}$ to $25.5{\pm}11.6%$, $30.5{\pm}5.6%$, and $96.0{\pm}2.7%$, respectively. The potency of $I_{K(Ado)}$ inhibition by GqPCRs was different with that observed in acetylcholine-activated GIRK currents ($I_{K(ACh)}$) (endothelin-1>phenylephrine>bradykinin). $I_{K(Ado)}$ was almost completely inhibited by $500\;{\mu}M$ of the $PIP_2$ scavenger neomycin, suggesting low $PIP_2$ affinity of $I_{K(Ado)}$. Taken together, these results suggest that the crosstalk between GqPCRs and the Ado-induced signaling pathway is receptor-specific. The differential change in $PIP_2$ affinity of GIRK channels activated by Ado and ACh may underlie, at least in part, their differential responses to GqPCR agonists.

• Journal of Chest Surgery
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• 제25권6호
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• pp.650-660
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• 1992

To elucidate a potential contribution of endotheline-1[ET-1] to the genesis of pulmonary hypertension and postoperative pulmonary hypertensive crisis in the patients with heart disease, we measured plasma levels of the ET-1 during perioperative period of open heart surgery. In addition, we examined changes of ET-1 during perioperative period and correlations between ET-1 levels and hemodynamic variables. 12 patients including 5 acquired heart disease and 7 congenital heart disease patients were selected randomly as a study group, Group A and B, respectively. 6 patients proved not having heart or hemodynamic problem were selected as a control, Group C. 110 blood samples from pulmonary artery[ET-P] and radial artery[ET-S] were taken and assayed by Sep-pak extraction and RIA. ET-1 levels of Group A were ET-P, 3.94$\pm$5.31pg /ml, ET-S, 3.10$\pm$2.90pg/ml[p>0.05], Group B were ET-P, 1.63$\pm$0.62pg/ml, ET-S, 1.99$\pm$2.45pg/ml[p>0.05], Group C were ET-P, 1.97$\pm$2.02pg/ml, ET-S, 1.72$\pm$0.77pg/ml[p>0.05]. There were no statistically significant differences of ET-1 levels among the Group A, B, C[p>0.05]. There was no correlation between pulmonary artery pressure[PAP] and ET-1 level[p>0.05], and ET-1 levels were not increased even in the cases of pulmonary hypertensive criwis or low cardiac output syndrome, whereas significant correlation between ET-S and pulmonary vascular res-istance[Rp] [r=0.36, p<0.05], and negative correlation between ET-S and OS saturation of pulmonary artery[OS-P][r= -0.49, p<0.01] were identified. Another significant finding was peak increase of ET-1 levels in the postoperative period 1 hour[p<0.05] and then gra-dualy decrease through the postoperative period. In conclusion, ET-1 has no correlation with PAP, whereas correlation with Rp, and inverse correlation with OS-P. It is suggested that ET-1 is neither the direct causative substance of pulmonary hypertension nor pulmonary vasospasm but there must be increased production of ET-1 in chronic pulmonary hypertensive state. Counter-regulatory mechanism to ET-1 is speculated during the pulmonary vasospasm.

• Childhood Kidney Diseases
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• 제18권1호
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• pp.36-41
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• 2014

목적: 요로감염은 특별한 가 없는 영아나 소아에서 흔한 세균 감염으로 요로감염은 소변배양검사를 통하여 진단되며, 빠르고 정확한 진단과 치료가 중요하다. 하지만 배뇨조절이 잘 안되는 소아에서 진단 과정에서 오류가 발생하기 쉽다. Urine Endothelin-1 (ET-1)은 사구체 혈관 손상 시 사구체간질 세포에서 나오는 물질로 이를 통하여서 요로감염의 조기 진단의 유용성을 알아보고자 하였다. 방법: 2012년 7월부터 2013년 7월까지 13개월간 발열을 주소로 중앙대학교 병원 소아청소년과에 내원한 18세 미만의 70명의 환자를 대상으로 전향적으로 비교 분석하였다. 소변배양검사상 요로감염으로 진단된 실험군과 요로감염으로 진단되지 않은 대조군으로 나누었으며, 0.3 mL의 소변을 이용하여 Enzyme-linked immunosorbent assay 방법을 통해 urine ET-1을 정량적으로 측정하였다. 결과: 실험군은 45명이었고, 대조군은 25명이었으며, 실험군의 소변배양검사에서 Escherichia coli 42명, Klebsiella pneumonia 2명, Enterococcus faecalis 1명이 배양되었으며, 상부요로감염은 19명, 하부요로감염은 26명이었다. Urine ET-1은 실험군에서 평균 $1.41{\pm}0.35$ pg/mL, 대조군에서 $0.33{\pm}0.07$ pg/mL으로 통계학적으로 유의한 차이를 보였으며(P=0.04), 상부와 하부 요로감염간의 정량적 수치에서 유의성은 없었다(P=0.552). Urine ET-1과 혈청 C-reactive protein, 혈청 내 백혈구 간의 연관성은 없었다(pearson 상관계수: 0.24, 0.19). 결론: Urine ET-1은 적은 양의 소변으로도 검사 할 수 있으며, 요로감염을 진단하는 데에 유의한 결과를 보였다.

• The Korean Journal of Physiology and Pharmacology
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• 제4권3호
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• pp.185-195
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• 2000

Vascular diseases are significant complications of diabetes mellitus (DM), and the endothelial cells may play a pivotal role in the development of vascular disease in DM. Endothelin-1 (ET-1) released from endothelium is a potent vasoconstrictor peptide and circulating level of ET-1 is increased in a variety of disease states. The purpose of this study was to determine the changes of responsiveness to ET-1 in DM, and we experimented on the changes in the ET-1-induced contraction, levels of nitrite and lipid peroxidation, and ET-1 immunoreactivity in aorta from streptozotocin-induced DM rats. DM was induced by single injection of streptozotocin (55 mg/kg, i.p.). The immunoreactive ET-1 levels in endothelial layer of thoracic aorta were much higher in DM rats than control rats. Nitrite in tissue homogenate was decreased and plasma nitrite was increased in DM rats. Malondialdehyde (MDA) was significantly increased in DM rats and cGMP was not significantly different between control and DM rats. ET-1 produced concentration- dependent contractile responses that are significantly attenuated in DM rats compared to controls. In the presence of selective $ET_A$ receptor antagonist BQ610, the maximum contraction was decreased and the concentration ratios for BQ610 yielded $pA_2$ values of 7.3 (slope, 0.65) in control rats, whereas BQ610 had no antagonistic effect on ET-1-induced contraction in DM rats. However, pretreatment with BQ788, an $ET_B$ receptor antagonist, maximum response was decreased and the dose-response curves for ET-1 were shifted to the right in both groups and $pA_2$ values were 7.9 and 7.7 (slope, 1.05 in control and DM rats), respectively. IRL 1620 and sarafotoxin S6c, $ET_B$ agonists, induced relaxation in control rats but not in DM rats. These results indicate that endothelial cell dysfunction and enhanced immunoreactivity of ET-1 have been found in DM rat and ET-1-induced contraction was attenuated in DM rat. These attenuated responses might be at least in part caused by the alteration of $ET_A$ receptor properties (e.g. desensitization), and partly related with an alteration in intracellular mechanism for contraction to ET-1.

• 한국자원식물학회지
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• 제33권5호
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• pp.467-475
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• 2020

고혈압은 성인의 수축기 혈압이 140 mmHg 이상이거나 이완기 혈압이 90 mmHg 이상일 때를 의미하며 고혈압은 뇌졸중, 신부전 및 관상동맥질환 등 인체 전반에 걸쳐 다양한 합병증을 일으키며 고혈압 유병자의 생명과 건강을 직접적으로 위협한다(Kim and Kim, 2018). 그러나 고혈압 유병자들은 증상이 거의 나타나지 않으므로 혈압을 측정하기 전까지는 진단되지 않는다. 진득찰 즉 한방에서 희렴은 고혈압을 치료하는 처방 제제로 주로 사용됐기에 이에 착안하여 털진득찰을 이용하여 엔도델린(Endothelin)로 강제 수축 시킨 토끼 기저동맥의 이완 효과를 평가하였다. 본 연구에서는 털진득찰(Sigesbeckia pubescens)의 전초를 이용하여 키레놀 화합물을 분리 후 혈관 이완 효과를 평가하였다. 인체 내 가장 강력한 혈관수축 물질로 알려진 엔도델린은 혈관 평활근 세포막에 존재하는 엔도델린 수용체 아형 A (ET_AR)와 혈관 내피세포막에 존재하는 수용체 아형 B2(ET_B2R)에 작용하여 혈관의 긴장도를 높이고, ET_B1R에 작용하여 긴장도를 낮추는 조절자 임무를 수행한다(Lucchelli et al., 1999). 일반적으로 엔도델린 펩타이드의 경우 염증, 당뇨, 및 심혈관계 질환에서 혈중 농도가 증가하며, 엔도델린 체계의 비정상적 항진은 만성신부전 및 사구체 경화증과 같은 신질환, 특발성 폐섬유화증 및 만성폐쇄성 폐 질환 등의 호흡기계 질환, 대사질환의 중요한 관심거리가 되는 당뇨병성 신경병증 및 망막증, 수족괴사 등의 질환과 전립선 및 대장 등의 암질환 등을 초래한다(Lavoie et al., 1997; Pancrazio et al., 1998). 본 연구에서 엔도델린 유도 뇌 기저동맥의 수축을 억제하는 키레놀의 농도(EC₅₀)를 관찰한 결과 10 ㎍/mL의 농도에서 48% 이상의 유효한 혈관 이완 효능이 관찰되었다. 따라서 키레놀을 이용하여 엔도델린 활성조절 신소재로의 구조적·기능적 도출 연구가 추가로 진행된다면건강 기능성 식품 소재 또는 의약학 소재로의 개발이 가시화될 수 있을 것으로 사료된다.

• The Korean Journal of Physiology and Pharmacology
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• 제20권1호
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• pp.9-14
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• 2016

Adenosine 3',5'-cyclic monophosphate (cAMP) participates in the regulation of numerous cellular functions, including the $Na^+-K^+$-ATPase (sodium pump). Ouabain, used in the treatment of several heart diseases, is known to increase cAMP levels but its effects on the atrium are not understood. The aim of the present study was to examine the effect of ouabain on the regulation of atrial cAMP production and its roles in atrial endothelin-1 (ET-1) secretion in isolated perfused beating rabbit atria. Our results showed that ouabain ($3.0{\mu}mol/L$) significantly increased atrial dynamics and cAMP levels during recovery period. The ouabain-increased atrial dynamics was blocked by KB-R7943 ($3.0{\mu}mol/L$), an inhibitor for reverse mode of $Na^+-Ca^{2+}$ exchangers (NCX), but did not by L-type $Ca^{2+}$ channel blocker nifedipine ($1.0{\mu}mol/L$) or protein kinase A (PKA) selective inhibitor H-89 ($3.0{\mu}mol/L$). Ouabain also enhanced atrial intracellular cAMP production in response to forskolin and theophyline ($100.0{\mu}mol/L$), an inhibitor of phosphodiesterase, potentiated the ouabain-induced increase in cAMP. Ouabain and 8-Bromo-cAMP ($0.5{\mu}mol/L$) markedly increased atrial ET-1 secretion, which was blocked by H-89 and by PD98059 ($30{\mu}mol/L$), an inhibitor of extracellular-signal-regulated kinase (ERK) without changing ouabain-induced atrial dynamics. Our results demonstrated that ouabain increases atrial cAMP levels and promotes atrial ET-1 secretion via the mitogen-activated protein kinase (MAPK)/ERK signaling pathway. These findings may explain the development of cardiac hypertrophy in response to digitalis-like compounds.

• Clinical and Experimental Pediatrics
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• 제56권3호
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• pp.116-124
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• 2013

Purpose: Tumor necrosis factor (TNF)-${\alpha}$ is thought to contribute to pulmonary hypertension. We aimed to investigate the effect of infliximab (TNF-${\alpha}$ antagonist) treatment on pathologic findings and gene expression in a monocrotaline-induced pulmonary hypertension rat model. Methods: Six-week-old male Sprague-Dawley rats were allocated to 3 groups: control (C), single subcutaneous injection of normal saline (0.1 mL/kg); monocrotaline (M), single subcutaneous injection of monocrotaline (60 mg/kg); and monocrotaline + infliximab (M+I), single subcutaneous injection of monocrotaline plus single subcutaneous injection of infliximab (5 mg/kg). The rats were sacrificed after 1, 5, 7, 14, or 28 days. We examined changes in pathology and gene expression levels of TNF-${\alpha}$, endothelin-1 (ET-1), endothelin receptor A (ERA), endothelial nitric oxide synthase (eNOS), matrix metalloproteinase (MMP) 2, and tissue inhibitor of matrix metalloproteinase (TIMP). Results: The increase in medial wall thickness of the pulmonary arteriole in the M+I group was significantly lower than that in the M group on day 7 after infliximab treatment (P<0.05). The number of intraacinar muscular arteries in the M+I group was lower than that in the M group on days 14 and 28 (P<0.05). Expression levels of TNF-${\alpha}$, ET-1, ERA, and MMP2 were significantly lower in the M+I group than in the M group on day 5, whereas eNOS and TIMP expressions were late in the M group (day 28). Conclusion: Infliximab administration induced early changes in pathological findings and expression levels of TNF-${\alpha}$, and MMP2 in a monocrotaline-induced pulmonary hypertension rat model.

• The Korean Journal of Physiology and Pharmacology
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• 제9권3호
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• pp.165-172
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• 2005

The aim of this study was to determine the roles of ET-1 and NO on uterine blood flow in pregnancy. Uterine arteries were isolated from 17 nonpregnant and 12 pregnant women. Nonpregnant group included patients with median age of $48.6{\pm}2.3$ years who underwent hysterectomy, because of myoma. Pregnant group included patients with median age of $31.3{\pm}1.4$ years undergoing cesarean delivery. ET-1 and ET-2 induced concentration-dependent contraction in isolated nonpregnant and pregnant uterine arteries. The contractile response and maximal contraction were increased in pregnant uterine arteries. In nonpregnant uterine arteries, there was no contraction in response to ET-3, whereas pregnancy induced concentration-dependent contraction by ET-3. Tissue nitrite/nitrate level and immunohistochemical staining of eNOS and iNOS were increased in pregnant uterine arteries, compared with nonpregnant uterine arteries. In addition, the expressions of eNOS and iNOS mRNA were significantly increased in pregnancy. Moreover, contractions by ET isopeptides, including ET-1, were enhanced, and immunohistochemical staining of ET-1 and ET-1 mRNA expression was increased in pregnant uterine arteries. These results suggest that NO production by increased NOS activity, especially eNOS activity, is related to placental and uterine blood flow. Furthermore, ET-1 appears to play a pathophysiological role in pregnant complications such as hypertension.