• Title, Summary, Keyword: angiotensin II

Search Result 231, Processing Time 0.045 seconds

Norepinephrine과 Angiotensin II의 혈압상승작용에 대한 Diltiazem의 영향

  • 고석태;임동윤;유강준;최홍석;심기정
    • Proceedings of the Korean Society of Applied Pharmacology
    • /
    • /
    • pp.298-298
    • /
    • 1994
  • Norepinephrine이나 angotensin II가 그 작용을 나타내는데 $Ca^{+2}$의 세포내 유입 또는 유출과 밀접한 관련이 있다는 관점에서 $Ca^{+2}$ -channel차단제중 benzothiazenpine계인 diltiazem의 norepinephrine과 angiotensin II의 혈압상승작용에 대한 영향을 가토에서 관찰하였다. Norepinephrine과 angiotensin II의 혈압상승작용에 대한 diltiazem의 영향을 관찰하는 경우는 diltiazem을 투여한 일정시간후에 norepinephrine이나 angiotensin II을 투여하여 나타나는 혈압변화를 diltiazem투여전의 norepinephrine이나 angiotensin II의 혈압상승치와 비교 검토하였다. Diltiazem은 norepinephrine과 angiotensin II의 혈압상승작용을 억재하였으나 그 억제 시간은 지속적이지 않았다. 이와는 달리 diltiazem투여 30-40분에는 norepinephrine의 혈압상승작용의 강화현상이 나타났다. Diltiazem은 교감신경말단차단제인 bethanidine이나 신경절 차단제인 chlorisondamine 처리 가토에서도 norepinephrine이나 angiotensin II의 혈압상승작용을 억제하였다.

  • PDF

The Effects of Glucose, Insulin and Angiotensin II on Plasminogen Activator Inhibitor-1 Expression and Growth of Aortic Vascular Smooth Muscle Cell in Rats (포도당, 인슐린 및 Angiotensin II가 흰쥐 대동맥평활근세포의 Plasminogen Activator Inhibitor-1 발현 및 성장에 미치는 영향)

  • 최세영;이인규;한승세;김재현;박창권;이광숙;유영선;김기식;김윤년
    • The Korean Journal of Thoracic and Cardiovascular Surgery
    • /
    • v.32 no.4
    • /
    • pp.333-340
    • /
    • 1999
  • Background: Plasminogen activator inhibitor-1(PAI-1) is known as the primary physiological inhibitor of tissue-type plasminogen activator(t-PA) in the plasma, and is present within the atherosclerotic vessels. Increased plasma levels of PAI-1 are one of the major disturbances of the hemostatic system in patients with diabetes and/or hypertension, and may have multiple interrelations with the important risk factors in the development of atherosclerosis. This study was performed to determine whether altered gene expression of PAI-1 occurs within the arterial wall, and thereby potentially contributing to the increase of cardiovascular risks associated with diabetes and/or hypertension. Material and Method: The aortic vascular smooth muscle cells of the rat were exposed to 22 mM glucose, angiotensin II, and insulin increased PAI-1 mRNA expression with the use of Northern blotting were examined. Also examined were the effects of 22 mM glucose, angiotensin II and insulin on the growth of the rat's aortic smooth muscle cells by using MTT assay. Result: Twenty-two mM glucose treatment increased the PAI-1 mRNA expression in a time- and dose-dependent manner. Aniotensin II treatment synergistically increased the glucose-induced PAI-1 mRNA expression. In contrast, addition of insulin attenuated the increase of 22 mM glucose and angiotensin II induced PAI-1 mRNA expression. Furthermore, treatment of 22 mM glucose, angiotensin II and insulin resulted in a significant increase in cell numbers. This study demonstrated that 22 mM glucose and angiotensin II have a synergistic effect in stimulating the PAI-1 mRNA expression and in the cell growth of the rat's aortic smooth muscle cells. Conclusion: Elevation of glucose and angiotensin II may be important risk factors in impairing fibrinolysis and developing atherosclerosis in diabetic patients.

  • PDF

Receptor-Ligand Binding Characteristics of KR-31064 (KR-31064의 수용체-리간드 결합특성에 대한 연구)

  • Lee, Sunghou
    • YAKHAK HOEJI
    • /
    • v.58 no.1
    • /
    • pp.16-20
    • /
    • 2014
  • KR-31064 was developed for the strong angiotensin II receptor antagonist among the one of pyridyl imidazol series compounds. To investigate the receptor-ligand binding characteristics of this nonpeptide antagonist, binding experiments were deployed in various conditions and ex vivo contractile responses were tested toward the standard compound, losartan. Receptor binding experiments with radiolabeled angiotensin II, the $IC_{50}$ value for KR-31064 resulted 0.67 nM without any activities toward type 2 angiotensin II receptor. The comparative potency against losartan was more than 18 fold and the specific activity in type 1 angiotensin II receptor was more than 10,000 fold comparing to the type 2 receptor. Scatchard analysis of saturation binding data showed KR-31064 acted on the receptor in a competitive mode. KR-31064 inhibited the contractile response derived by angiotensin II ($pK_B$: 9.86) similar to that of losartan with decreased maximum signals. As a potent and specific type 1 angiotensin II receptor antagonist, KR-31064 may have possibilities for the development of diagnostic ligands that can be used as tools for various biochemical research experiments and non-invasive diagnostics.

Identification of Phosphatidylcholine-Phospholipase D and Activation Mechanisms in Rabbit Kidney Proximal Tubule Cells

  • Chung, Jin-Ho;Chae, Joo-Byung;Chung, Sung-Hyun
    • BMB Reports
    • /
    • v.29 no.1
    • /
    • pp.11-16
    • /
    • 1996
  • The present study showed that receptor-mediated activation of rabbit kidney proximal tubule cells by angiotensin II, the $Ca^{2+}$ ionophore A23187, or the protein kinase C activator phorbol myristate acetate (PMA) all stimulated phospholipase D (PLD). This was demonstrated by the increased formation of phosphatidic acid, and in the presence of 0.5% ethanol, phosphatidylethanol (PEt) accumulation. Angiotensin II leads to a rapid increase in phosphatidic acid and diacylglycerol, and phosphatidic acid formation preceeded the formation of diacylglycerol. This result suggests that some phosphatidic acid seems to be formed directly from phosphatidylcholine hydrolyzed by Pill. On the other hand, EGTA substantially attenuated angiotensin II and A23187-induced PEt formation, and when the cells were pretreated with verapamil angiotensin II-induced Pill activation was completely abolished. These results provide the evidence that calcium ion influx is essential for the agonist-induced Pill activation. In addition, staurosporine, an inhibitor of protein kinase C, strongly inhibited PMA-induced PEt formation, but was ineffective on angiotensin II-induced PEt accumulation. $GTP{\gamma}S$ also stimulates PEt formation in digitonin-permeabilized cells, but pretreatment of the cells with pertussis toxin failed to suppress angiotensin II-induced PEt formation. From these results, we conclude that in the rabbit kidney proximal tubule cells the mechanisms of angiotensin II- and PMA-induced Pill activation are different from each other and mediated via a pertussis toxin-insensitive trimeric G protein.

  • PDF

Effect of Unilateral Renal Arterial Infusion of Angiotensin II on Renal Function and Renin Secretion in Unanesthetized Rabbit (신동맥내 투여한 Angiotensin II가 신장기능 및 Renin 분비에 미치는 영향)

  • Kim, Jong-Hun;Kang, Nam-Poo;Kim, Young-Jin;Kim, Suhn-Hee;Cho, Kyung-Woo
    • The Korean journal of physiology & pharmacology
    • /
    • v.23 no.2
    • /
    • pp.363-375
    • /
    • 1989
  • It has been well known that peripheral infusion of angiotensin II results in an increase of blood pressure, and an elevation of aldosterone secretion, and an inhibition of renin relase. However, the direct effect of angiotensin II on renal function has not been clearly established. In the present study, to investigate the effect of angiotensin II on renal function and renin release, angiotensin II (0.3, 3 and 10 ng/kg/min) was infused into a unilateral renal artery of the unanesthetized rabbit and changes in renal function and active and inactive renin secretion rate (ARSR, IRSR) were measured. In addition, to determine the relationship between the renal effect of angiotensin II and adenosine, the angiotensin II effect was evaluated in the presence of simultaneously infused 8-phenyltheophylline (8-PT, 30 nmole/min), adenosine A 1 receptor antagonist. Angiotensin II infusion at dose less than 10 ng/kg/min decreased urine flow, clearances of para-amino-hippuric acid and creatinine, and urinary excretion of electrolytes in dose-dependent manner. The changes in urine flow and sodium excretion were significantly correlated with the change in renal hemodynamics. Infusion of angiotensin II at 10 ng/kg/min also decreased ARSR, but it has no significant effect on IRSR. The change in ARSR was inversely correlated with the change in IRSR. The plasma concentration of catecholamine was not altered by an intarenal infusion of angiotensin II. In the presence of 8-PT in the infusate, the effect of angiotensin II on renal function was significantly attenuated, but that on renin secretion was not modified. These results suggest that the reduction in urine flow and Na excretion during intrarenal infusion of angiotensin II was not due to direct inhibitions of renal tubular transport systems, but to alterations of renal hemodynamics which may partly be mediated by the adenosine receptor.

  • PDF

Pharmacophore Modeling of Angiotensin-Ⅱ from Study of Its Nonpeptidic Antagonists

  • 오원석;신항철;정낙철;신재민
    • Bulletin of the Korean Chemical Society
    • /
    • v.17 no.2
    • /
    • pp.182-188
    • /
    • 1996
  • Early attempts to identify plausible conformations of a linear octapeptide hormone, angiotensin-II (Asp-Arg-Val-Tyr-Ile-His-Pro-Phe), using various theoretical and experimental methods, have led to various conformational models. So far, no consensus has been made about the solution phase structure and the receptor binding structure of angiotensin-II. The ultimate goal for the conformation study of the peptide hormone is to develop a new potent drug. Therefore, we have devised a strategy for designing the pharmacophore by studying thermodynamically possible conformations of various kinds of angiotensin-II antagonists and angiotensin-II.

  • PDF

The Relationship of Serum Angiotensin Converting Enzyme(ACE), Angiotensin II and Clinical Markers in the Idiopathic Interstitial Pneumonia (특발성 간질성 폐렴 환자에서 임상적 지표와 혈청 Angiotensin Converting Enzyme(ACE) 및 Angiotensin II와의 관계)

  • Kyung, Sung-Young;Hahn, Hye-Sook;Song, Suk-Ho;Hwang, Jun-Kyu;Lim, Young-Hee;An, Chang-Hyeok;Park, Gye-Young;Park, Jung-Woong;Jeong, Seong-Hwan;Ha, Seung-Yeon;Lee, Jae-Woong
    • Tuberculosis and Respiratory Diseases
    • /
    • v.52 no.5
    • /
    • pp.506-518
    • /
    • 2002
  • Background : There have been several studies showing that angiotensin II and the angiotensin converting enzyme (ACE) contribute to the activation of fibroblast including the pulmonary fibrosis, and apoptosis of the alveolar epithelium in idiopathic intersititial pneumonia. This study was performed to identify the relationship between the serum angiotensin II, ACE and the pulmonary function test (PFT), the dyspnea score, and the cell fraction of the bronchoalveolar lavage fluid(BALF). Materials and Methods : Twenty three patients with idiopathic interstitial pneumonia from March, 1999 to October, 2001 at Gachon medical school were enrolled in this study. They were divided into IPF(UIP) (16) and NSIP (7) groups. Twelve of the idiopathic interstitial pneumonia patients (UIP : 5, NSIP : 7) were diagnosed by an open lung biopsy, 11 of IPF patients were diagnosed by the American Thoracic Society (ATS) diagnostic criteria. The PFT values, dyspnea score, serum ACE and angiotensin II were measured, and a bronchoscopy was performed to obtain the BALF. Results : Of all the patients, 7 were in the normal range and 14 showed an increase in the serum level of angiotensin II. In terms of the serum ACE level, 14 patients had an increased level. The DLCO% of the angiotensin II in increased group was significantly lower than the not-increased group (p=0.021). Other factors did not correlate with the serum ACE or the angiotensin II increased group and not-increased group. Conclusion : These results suggest that an increased angiotensin II serum level may be associated with increase in the of alveolar capillary block in the progression of pulmonary fibrosis in idiopathic interstitial pneumonia.

Solubilization of an Angiotensin II Binding Site from Rat Liver

  • Chung, Sung-Hyun;Ravi Iyengar
    • Archives of Pharmacal Research
    • /
    • v.14 no.3
    • /
    • pp.231-236
    • /
    • 1991
  • The high affinity binding sites for angiotensin II were solubilized from rat liver membranes by treatment with CHAPS. The binding protein was also partially purified by angiotensin III inhibitor-coupled Affi-gel affinity chromatography. Binding to the intact membrances as well as to the solubilized preparation was specific and saturable. According to the Scatchard plot, the membrane preparations exhibited a single class of high affinity binding sites with a Kd OF 0.71 nM. The solubilized preparation also showed the presence of a single class of bindings sites with less affinity (Kd of 14 nM). Meanwhile the competition studies using angiotensin II analogues represented two separate binding sites for angiotensin II and single binding site for antagonist. These latter findings were correlated to the results provided by Garrison's research group. More works are needed to clarify this discrepancy.

  • PDF

A Protein Tyrosine Phosphatase Inhibitor, Pervanadate, Inhibits Angiotensin II-Induced β-Arrestin Cleavage

  • Jang, Sei-Heon;Hwang, Si Ae;Kim, Mijin;Yun, Sung-Hae;Kim, Moon-Sook;Karnik, Sadashiva S.;Lee, ChangWoo
    • Molecules and Cells
    • /
    • v.28 no.1
    • /
    • pp.25-30
    • /
    • 2009
  • ${\beta}$-Arrestins turn off G protein-mediated signals and initiate distinct G protein-independent signaling pathways. We previously demonstrated that angiotensin $AT_1$ receptorbound ${\beta}$-arrestin 1 is cleaved after $Phe^{388}$ upon angiotensin II stimulation. The mechanism and signaling pathway of angiotensin II-induced ${\beta}$-arrestin cleavage remain largely unknown. Here, we show that protein Tyr phosphatase activity is involved in the regulation of ${\beta}$-arrestin 1 cleavage. Tagging of green fluorescent protein (GFP) either to the N-terminus or C-terminus of ${\beta}$-arrestin 1 induced conformational changes and the cleavage of ${\beta}$-arrestin 1 without angiotensin $AT_1$ receptor activation. Orthovanadate and molybdate, inhibitors of protein Tyr phosphatase, attenuated the cleavage of C-terminal GFP-tagged ${\beta}$-arrestin 1 in vitro. The inhibitory effects of okadaic acid and pyrophosphate, which are inhibitors of protein Ser/Thr phosphatase, were less than those of protein Tyr phosphatase inhibitors. Cell-permeable pervanadate inhibited angiotensin II-induced cleavage of ${\beta}$-arrestin 1 in COS-1 cells. Our findings suggest that Tyr phosphorylation signaling is involved in the regulation of angiotensin II-induced ${\beta}$-arrestin cleavage.