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目的 观察模拟失重对大鼠肾动脉收缩功能的影响及Rho相关蛋白激酶(Rho-associated protein kinase,ROCK)与其关系。方法 以大鼠尾部悬吊4周建立模拟失重模型,采用离体血管环功能实验检测大鼠肾动脉收缩反应变化,通过免疫蛋白印迹技术检测大鼠肾动脉ROCK蛋白的表达,采用ROCK活性试剂盒检测ROCK活性。结果 模拟失重大鼠肾动脉苯肾上腺素(Phenylephrine,PE)与氯化钾(KCl)诱导的收缩反应均明显降低(P<0.05),ROCK特异性抑制剂 Y-27632显著缩小模拟失重大鼠与正常大鼠动脉收缩反应之间的差异(P<0.05);蛋白印迹结果显示,模拟失重大鼠肾动脉ROCK蛋白表达增加(P<0.05);ROCK活性检测结果显示,模拟失重大鼠肾动脉ROCK活性降低(P<0.05)。结论 模拟失重大鼠肾动脉收缩反应明显降低,抑制ROCK的作用可减小模拟失重大鼠与正常大鼠肾动脉收缩功能的差异,ROCK活性改变可能在模拟失重大鼠肾动脉收缩功能降低中发挥一定作用。 相似文献
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目的 观察过氧亚硝酸盐对糖尿病大鼠胸主动脉血管收缩功能的影响.方法 雄性SD大鼠30只,大鼠随机分为3组:对照组、糖尿病组和糖尿病+尿酸盐孵育(过氧亚硝酸盐清除剂)组.以去除内皮的大鼠胸主动脉作为实验标本.分别检测各组血管收缩功能、RhoA/ROCK表达水平和硝基酪氨酸表达水平的差异.结果 糖尿病组血管的收缩反应增强.糖尿病组与尿酸盐孵育组相比,RhoA mRNA表达水平升高.糖尿病组血管ROCK的蛋白表达水平显著升高.糖尿病组血管硝基酪氨酸表达水平显著升高.结论 过氧亚硝酸盐导致糖尿病大鼠胸主动脉血管ROCK蛋白表达水平增加及血管收缩反应增强. 相似文献
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目的:观察模拟失重大鼠胸主动脉平滑肌细胞凋亡的变化及间断性人工重力对其影响。方法: 将27只SD大鼠随机分为3组(每组9只),即对照组(CON)、模拟失重组(SUS)及站立对抗组(STD)。以尾部悬吊大鼠模拟失重3周,同期每天悬吊23 h、站立1 h模拟间断性人工重力对抗的效果。用TUNEL染色法检测SUS组、同步对照(CON)组及STD组大鼠胸主动脉平滑肌细胞的凋亡情况;用Western blot法检测各组大鼠胸主动脉组织中Bad、FasL及Caspase-3蛋白表达的变化。结果: 与CON组比较,SUS组大鼠胸主动脉平滑肌细胞TUNEL染色阳性的细胞明显减少(P<0.01);STD组TUNEL染色阳性的细胞较CON组及SUS组显著增加(P<0.01)。SUS组Bad的表达较CON组和STD组显著减少(P<0.05),STD组Bad的表达较CON组有增加的趋势,但无统计学差异。SUS组FasL及Caspase-3的表达较CON组显著降低(P<0.05);STD组FasL及Caspase-3的表达较CON组及SUS组显著增高(P<0.01)。结论: 模拟失重可减少大鼠胸主动脉平滑肌细胞凋亡,每日1 h的-Gx对抗可使胸主动脉平滑肌细胞的凋亡增加,提示血管组织平滑肌细胞的凋亡在失重引起的动脉血管适应性重构中可能发挥重要作用。 相似文献
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《肾脏病与透析肾移植杂志》2018,(5)
目的:探讨慢性肾脏病(CKD)继发高血压与主动脉舒缩功能改变之间的关系及其机制。方法:(1)造模:将正常SD大鼠随机分为假手术组(对照组)和CKD组,通过5/6肾切除法制作大鼠CKD模型。术前、术后8周、术后16周分别检测血清肌酐、钙、磷、甲状旁腺素水平,术前及第16周测量大鼠血压。(2)主动脉张力测定:第16周处死大鼠,镜下选取胸主动脉制备血管环,采用累积浓度给药法分别予血管收缩剂与血管舒张剂,通过血管张力测定仪观察血管张力的变化。(3)采用Western Blot检测胸主动脉上相应的受体蛋白表达。结果:(1)第16周时CKD组大鼠血清肌酐、血钙、血磷、甲状旁腺素和尾动脉收缩压及舒张压较对照组均明显升高。(2)CKD大鼠胸主动脉对血栓素A2类似物(U46619)刺激下产生的收缩力明显增强(162. 66±14. 29 vs 121. 39±15. 47,P0. 01);对60 mmol/L的氯化钾和苯肾上腺素(Phe)诱导的收缩,两组未见明显差异。(3) CKD组大鼠胸主动脉环对内皮依赖性血管舒张剂乙酰胆碱(Ach)和非内皮依赖性血管舒张剂硝普钠(SNP)所触发的舒张反应均低于对照组,Ach(67. 78±6. 18 vs 83. 92±5. 42,P0. 01),SNP(95. 45±1. 33 vs 98. 90±0. 60,P0. 01)。(4) CKD组大鼠胸主动脉上血栓素A2受体蛋白(TXA2受体)表达较对照组明显增多,肾上腺素受体蛋白及L-型钙通道(Cav1. 2)蛋白表达无差异。结论:CKD组大鼠胸主动脉对TXA_2类似物刺激收缩力增强,其原因可能与血管上TXA2受体蛋白增多有关;同时CKD大鼠胸主动脉的内皮及非内皮依赖性舒张功能均有受损,这些变化可能参与了CKD高血压大鼠主动脉收缩高反应性。 相似文献
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目的观察模拟失重2周后,大鼠脑动脉血管平滑肌细胞(vascular smooth muscle cells,VSMCs)L型电压依赖性钙离子通道(L-type voltage dependent calcium channel,CaL)功能的改变,以及钙通道激动剂BayK8644对通道电流的影响。方法以尾部悬吊大鼠模型模拟失重的影响。采用全细胞膜片钳记录模式,以Ba2+作为载流子,记录2周模拟失重后大鼠脑动脉VSMCs的CaL电流及钙通道激动剂Bay K 8644对其的影响,并测定相应的稳态激活与失活曲线及有关参数。结果与对照组相比,模拟失重2周后悬吊组大鼠已出现了典型的模拟失重效应,悬吊组大鼠脑动脉VSMCs的CaL的电流密度显著增加(P<0.05),且对钙通道激动剂Bay K 8644更敏感(P<0.05)。此外,与对照组相比,悬吊组大鼠脑动脉VSMCs的膜电容与接入电阻、CaL稳态失活曲线和稳态激活曲线等通道动力学特征无显著性改变。结论模拟失重2周可引起大鼠脑动脉平滑肌细胞CaL通道功能增强,这可能是模拟失重导致大鼠脑动脉血管收缩反应性增强的因素之一。 相似文献
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目的:研究尾吊模拟失重状态下大鼠胃窦和空肠黏膜白介素2(interleukin-2,IL-2)及生长抑素(somatostatin,SS)免疫反应细胞的变化. 方法:采用尾部悬吊模拟失重,将大鼠分为悬吊14 d组和28 d组及相应同步对照组.以免疫组织化学方法,观察大鼠胃窦和空肠黏膜IL-2及SS免疫反应细胞的变化. 结果:与正常对照组相比,在胃窦部黏膜14 d尾部悬吊大鼠IL-2免疫反应细胞有下降趋势,但统计学分析无明显差异,28 d悬吊组则明显减少(P<0.01);14 d和28 d悬吊组SS免疫反应细胞均明显减少(P<0.01).与正常对照相比, 在空肠黏膜14 d及28 d悬吊组IL-2免疫反应细胞无明显变化(P>0.05);14 d及28 d悬吊组SS免疫反应细胞减少(P<0.05及P<0.01). 结论:模拟失重状态下,IL-2在大鼠胃窦部的表达下降. 在空肠变化不明显;而SS在大鼠胃窦及空肠的表达均下降. 提示其免疫及内分泌功能发生了改变. 相似文献
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Ruth M. López Janette E. López Jorge S. López María C. Castillo Gustavo Guevara José A. Morales 《Clinical and experimental hypertension (New York, N.Y. : 1993)》2017,39(3):210-219
In endothelium-denuded abdominal (but not thoracic) aortas of rats, the nonselective cyclooxygenase (COX) inhibitor, indomethacin, suppressed contractions evoked by α-adrenergic agonists hypothetically mediated by prostanoids. We aimed to identify these non-endothelial-derived contractile prostanoids released by α-adrenergic receptors activation. Endothelium-denuded abdominal and thoracic aortas of Wistar rats were used for biochemical and functional analyses. Western blot analysis showed that COX-1 and COX-2 protein levels were respectively equivalent in endothelium-denuded abdominal and thoracic aortas. Enzyme immunoassay data supported direct evidence of phenylephrine-stimulated release of prostanoids (PGI2, PGE2, and PGF2α) by thoracic and abdominal aortas without endothelium, and their almost complete inhibition by 1 μM indomethacin. Isometric force measurements established that 10 μM indomethacin—but no lower concentrations—inhibited the contractions evoked by phenylephrine in endothelium-denuded abdominal aorta. In this preparation, 10 μM indomethacin also depressed the contractions provoked by angiotensin II and high K+ (80 mM). In fact, indomethacin (up to 1 mM) caused concentration-dependent reductions in all abovementioned contractile responses. In endothelium-denuded thoracic aortas, however, only 1 mM indomethacin significantly depressed the contractile activity stimulated by either phenylephrine, angiotensin II, or high K+. Hence, there was a clear quantitative difference in response to indomethacin between abdominal and thoracic aortas without endothelium. Altogether, the results indicate that prostanoids induced by phenylephrine in abdominal and thoracic aortas were derived from non-endothelial COX-mediated metabolism; notably, the decrease in prostanoid synthesis could not account for the inhibition of vasoconstrictor responses by indomethacin: Through COX-independent actions, indomethacin inhibited aortic smooth muscle contractility. 相似文献
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We studied the role of endothelium and eicosanoids in rhythmic contractions of rat thoracic aorta. Spontaneous oscillations were observed in 35% of 385 endothelium-intact and in 46% of 22 endothelium-denuded aortic strips from normotensive Sprague-Dawley male rats. Vasoactive agents (norepinephrine, epinephrine, phenylephrine, isoproterenol, arachidonic acid, PGF2 alpha, serotonin, potassium, endothelin, atrial natriuretic factor and angiotensin II) induced rhythmic contractions in the majority of tissues. Rhythmic activity was also observed in aortic strips from adult female, pregnant and old male rats. Aortic oscillations were partially inhibited by indomethacin, ibuprofen and nordihydroguaiaretic acid (NDGA), and completely inhibited by indomethacin plus NDGA, nifedipine, low external calcium (less than 1 mM) and pretreatment with dexamethasone. Indomethacin, NDGA and arachidonic acid did not affect oscillations of the portal vein. Rhythmic contractions were observed in thoracic aortic strips from neonatal but not from adult rabbits. However, oscillations could be induced in strips of the mesenteric artery and terminal abdominal aorta of adult rabbits. Also, adult rabbit thoracic aortic strips exhibited oscillations when set up in close proximity of rat aorta. It is suggested that rhythmic contractions are physiological characteristics of many and perhaps all blood vessels and may play a role in blood flow and turbulence; the likely cause of these oscillations is the cyclic release of one or more eicosanoids. 相似文献
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OBJECTIVE: The study was designed to investigate the role of calcium channels in enhanced angiotensin II (Ang II)-induced contraction in thoracic aortic rings from diabetic rats. METHODS: Ang II-induced isometric tension was studied in thoracic aortic rings isolated from control or streptozotocin-induced (8 weeks) diabetic rats. Saturation binding studies at AT1 receptors and L-type calcium channels were performed using [3H] Ang II and [3H] PN200110, respectively. Ang II-induced calcium influx was studied in fura-2-loaded single vascular smooth muscle cells isolated from thoracic aorta of control and diabetic rats. RESULTS: Ang II did not induce contraction in calcium-free Krebs. In the presence of extracellular calcium, increased Emax (mg/mm2) and pD2 to Ang II was observed in aortic rings from diabetic (795.54+/-38.19; 8.27+/-0.12) compared to control (230.09+/-25.45; 7.68+/-0.22) rats, respectively. Nimodipine but not verapamil or diltiazem dose-dependently blocked the Ang II-induced contractions in a noncompetitive manner and its -log IC50 was significantly lower in aortic rings from diabetic (8.81+/-0.10) compared to control (9.34+/-0.11) rats. The Ang II-induced increase in intracellular calcium levels was significantly enhanced (2.5-fold) in vascular smooth muscle cells from diabetic rats. AT1 receptor saturation binding with [3H] Ang II revealed a significantly higher affinity (nM) and Bmax (pmol/mg protein) in aortic vascular membrane preparation from diabetic (0.31+/-0.04; 64.18+/-2.4) compared to control (0.52+/-0.02; 47.81+/-2.8) rats, respectively, while L-type calcium channel saturation binding with [3H] PN200110 showed a higher affinity (nM) with no change in the Bmax (fmol/mg protein) in diabetic (0.74+/-0.08; 4.52+/-0.40) compared to control (1.49+/-0.32; 5.43+/-0.60) aortic membranes, respectively. CONCLUSIONS: Our results suggest that Ang II-induced contraction is dependent on extracellular calcium, and enhanced functional coupling of AT1 receptors and DHP-sensitive L-type calcium channels results in supersensitivity to Ang II in thoracic aorta isolated from diabetic rats. 相似文献