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The effects of cyclosporine A (CsA) on Angiontensin Ⅱ (Ang Ⅱ )-induced protein contents, c-fos protein levels and cytosolic Ca2+ level ([Ca2+ ]i) in cultured cardiomyocytes of neonatal rats were observed. Total protein contents were determined by Bradford method. The expression of c-fos protein was detected by Western blot. [Ca2+ ]i labeled with fluorescent probe Fluo-3/AM was measured under a laser scanning confocal microscope. The results revealed that as compared with control, the total protein contents were increased in cardiomyocytes treated with Ang Ⅱ (10-7 mol/L), which could be inhibited by CsA in a dose-dependent manner. It was found that Ang Ⅱ could increase the c-fos protein expression, which could be inhibited by CsA in a dose-dependent manner.Ang Ⅱ induced the [Ca2+ ]i elevation in cardiomyocytes. CsA did not influence the resting intracellular Ca2+ , but inhibited significantly the Ang Ⅱ-induced [Ca2+ ]i elevation. It was concluded that CsA can suppress the Ang Ⅱ-induced c-fos protein expression and [Ca2+ ]i elevation in single cardiomyocyte, which might play a role in the prevention of Ang Ⅱ -induced cardiomyocyte hypertrophy by CsA.  相似文献   

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通过^3H-Leu掺入量的测定与RNA狭线杂交技术,初步探讨血管紧张素Ⅱ受体,Ca^2+在血管紧张素Ⅱ刺激乳鼠心肌细胞蛋白质合成中的作用,并观察血管紧张素Ⅱ对原癌基因c-fos表达,结果发现培养液中加入钙通道阻断剂(verapamil),细胞外钙螯合剂(EGTA),肌浆网钙释放抑制剂(dantrolene)和细胞内钙螯合剂(Fura-2/AM)可使血管紧张素Ⅱ介导的^3H-Leu掺入量较单独加血管  相似文献   

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Summary Using the method of dual-wavelength measurement of platelet [Ca2+]i and Fura-2 as the Ca2+ fluorophore probe, we measured the effect of acidic Mucopolysaccharide fromSticopus Japonicus Selenka (SJAMP) on platelet [Ca2+]i. The results showed that the most significant increase in platelets [Ca2+]i was seen when the concentration of SJAMP was 100μg/ml and the elevation of normal platelet [Ca2+]i was 93.96 ± 10.24 nmol/L (n=10). In the presence of extracellular Ca2+ (1 mmol/L), the magnitude of platelet [Ca2+]i response to SJAMP was increased and the [Ca2+]i could reach 116.72±10. 66 nmol/L (n = 10). On the other hand, the magnitude of increased platelet [Ca2+]i induced by SJAMP was smaller and the duration of [Ca2+]i reaching the highest level was longer when compared with other platelet aggregation agents. In the mean time, if platelets were first incubated with cyclooxygenase inhibitor, the rise of [Ca2+]i evoked by SJAMP was inhibited. The results indicated that the mechanism of the rise of [Ca2+]i induced by SJAMP might be dependent upon the generation of prostaglandin endoperoxides and(or) TXA2. This project was supported by grant from the National Nature Science Foundation of China (No. 39370322).  相似文献   

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Summary In order to investigate the feasibility of angiotensin converting enzyme inhibitors (ACEIs) in preventing the development of atherosclerosis and restenosis after coronary angioplasty and to study their mechanisms, we measured the platelet cytosilic free Ca2+ concentration ([Ca2+]i) and observed the effects of captopsil on platelet [Ca2+]i in rabbits and also observed the inhibitive action on fibroblast proliferation in culture. The results showed that resting platelet [Ca2+]i, ADPor thrombin-stimulated platelet elevation amplitude after administration of captopril (12.5 mg, twice daily) for 15 days were significantly reduced in comparison with those before administration. And captopril also significantly inhibited fibroblast proliferation or reduced3H-thymidine (3H-TdR) incorporation in culture in a dose-depdendent manner. These findings suggest that ACEIs are promising drugs to reduce restenosis incidence after coronary angioplasty and to prevent atherosclerosis as well as provide a new explanation for their effects of suppressing cell proliferation.  相似文献   

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Objective: To explore the effects of total flavonoids ofHippophae rhamnoides L. (TFH), quercetin (Que) and isorhamnetin (Isor) on the intracellular free calcium ([Ca2+ ]i) in vascular smooth muscle cells (VSMC) of spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY).Methods: Fluo 3-acetoxymethylester(Fluo-3/AM) was used to observe the effects of TFH (100mg/L) and its essential monomers, namely Que (l0-4 mol/L) and Isor (l0-4 mol/L) on changes of [Ca2+]i in cultured SHR and WKY VSMC (abbr. to Ca-SHR & Ca-WKY) following exposure to high K+, norepinephrine (NE) and angiotensin II (Ang II), and to compare with the effects of verapamil (Ver).Results: (1) TFH, Que and Isor had inhibitory effects on resting Ca-SHR (P<0.05), but had no significant effects on Ca-WKY (P>0.05). (2) High K+ could increase Ca-SHR more significantly than Ca-WKY (P<0.05); TFH, Que and Isor could inhibit the elevation of [Ca2+]i induced by high K+-depolarization, with the effects similar to that of Ver, and the effect on Ca-SHR was more significant than that on Ca-WKY (P<0.05). (3) NE and Ang II could increase Ca-SHR more significantly than Ca-WKY (P<0.05), TFH, Que and Isor had remarkably inhibitory effect on the elevation of Ca-SHR and Ca-WKY induced by NE or Ang II. (4) In the absence of extracellular Ca2+, TFH, Que and Isor also had certain inhibitory effect on Ca-SHR and Ca-WKY induced by NE, and the effect on the former was more significant than that on the latter(P<0. 05).Conclusion: TFH, Que and lsor might decrease the levels of [Ca2+]i in VSMCs by blocking both voltage-dependent calcium channels (VDC) and receptor-operated calcium channels (ROC) in physiological or pathological state, which may be one of the important mechanisms of their hypotensive and protective effects on target organs in patients with hypertension. Supported by One-hundred-people Plan of Hygiene System in Shanghai (No. 990122)  相似文献   

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为探讨2-甲基-3-羟基蒽醌抗肿瘤作用及其机制,本研究采用锥虫蓝法检测细胞活力,流式细胞仪检测细胞周期变化、细胞凋亡率、线粒体膜电位及细胞内游离钙的变化,Western blot方法检测凋亡相关蛋白caspase-4、caspase-7、caspase-9、Bcl-2、Bax、JNK、细胞色素C的表达。结果发现:2-甲基-3-羟基蒽醌时间依赖性地抑制乳腺癌细胞的生长,升高细胞内游离钙含量,降低线粒体膜电位并诱导其凋亡;药物上调Bax并下调Bcl-2蛋白的表达;诱导caspase-4、caspase-7、caspase-9、calpain的活化及细胞色素C的释放。结果提示2-甲基-3-羟基蒽醌可能通过Ca2+/calpain/caspase-4途径诱导人乳腺癌MCF-7细胞凋亡。  相似文献   

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Summary To investigate the relationship between intracellular free Ca2+ concentration ([Ca2+]i) and calcium-activated chloride (ClCB) channels of pulmonary artery smooth muscle cells (PASMCs) in rats under acute and chronic hypoxic conditions, acute hypoxia-induced contraction was observed in rat pulmonary artery by using routine blood vascular perfusionin vitro. The fluorescence Ca2+ indicator Fura-2/AM was used to observe [Ca2+]i of rat PASMCs under normal and chronic hypoxic condition. The effect of ClCB channels on PASMCs proliferation was assessed by MTT assay. The ClCB channel blockers niflumic acid (NFA) and indaryloxyacetic acid (IAA-94) exerted inhibitory effects on acute hypoxia-evoked contractions in the pulmonary artery. Under chronic hypoxic condition, [Ca2+]i was increased. Under normoxic condition, [Ca2+]i was (123.63±18.98) nmol/L, and in hypoxic condition, [Ca2+]i was (281.75±16.48) nmol/L (P<0.01). Under normoxic condition, [Ca2+]i showed no significant change and no effect on ClCB channels was observed (P>0.05 Chronic hypoxia increased [Ca2+]i which opened ClCB channels. The NFA and IAA-94 blocked the channels and decreased [Ca2+]i from (281.75±16.48) nmol/L to (117.66±15.36) nmol/L (P<0.01). MTT assay showed that under chronic hypoxic condition NFA and IAA-94 decreased the value of absorbency (A value) from 0.459±0.058 to 0.224±0.025 (P<0.01). Hypoxia increased [Ca2+]i which opened ClCB channels and had a positive-feedback in [Ca2+]i. This may play an important role in hypoxic pulmonary hypertension. Under chronic hypoxic condition, ClCB channel may play a part in the regulation of proliferation of PASMCs. YANG Zhao, female, born in 1967, Doctor in Charge  相似文献   

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