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目的观察甲状腺功能亢进大鼠大脑基底动脉及肠系膜小动脉血管反应性的变化,深入探讨甲亢对动脉血管系统功能的影响。方法体质量350 g左右的16只雄性SD大鼠,随机分为对照组与甲亢组,采用左旋甲状腺素(左旋T4,优甲乐)0.6 mg/(kg.d)给大鼠灌胃25 d,建立甲亢大鼠模型。利用离体动脉环测定大脑基底动脉、肠系膜小动脉血管的反应性。结果甲亢组与对照组相比,基底动脉及肠系膜小动脉对氯化钾(10100 mmol/L)与苯肾上腺素(10-910-4mol/L)引起的收缩反应均显著减弱(P<0.05);对乙酰胆碱(10-910-4mol/L)引起的舒张反应均显著增强(P<0.05);对硝普钠(10-910-4mol/L)引起的舒张反应均无明显变化。甲亢组大鼠基底动脉及肠系膜小动脉对氯化钾和乙酰胆碱反应的敏感性增强(P<0.05),对苯肾上腺素和硝普钠反应的敏感性无明显差别。结论甲状腺功能亢进大鼠基底动脉及肠系膜小动脉收缩反应性降低,而内皮介导的舒张反应性增强。 相似文献
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目的 探讨增龄对大鼠肠系膜动脉平滑肌细胞大电导钙激活钾通道 (BKCa) α和β1亚基蛋白表达的影响。方法 选用不同年龄雄性Wistar大鼠,分为青年组(4~5月龄)、中年组(15~16月龄)和老年组(22~24月龄)。分别进行在体血压监测和离体去内皮血管张力测定,并采用蛋白免疫印迹分析观察肠系膜动脉平滑肌细胞BKCa通道α和β1亚基的表达。结果 增龄导致大鼠收缩压和脉压显著增大。去甲肾上腺素诱发各组肠系膜动脉收缩,并呈浓度依赖性,增龄导致血管对去甲肾上腺素的敏感性(pD2)和最大收缩反应降低;BKCa通道选择性阻断剂Iberiotoxin诱发各组血管张力增高,但增高幅度青年组>中年组>老年组。蛋白免疫印迹分析显示α和β1亚基均随增龄下降,但β1亚基下降幅度显著大于α亚基。结论 增龄诱导大鼠肠系膜动脉BKCa通道在血管张力维持中的贡献下降,其分子机制可能为增龄诱发的α和β1亚基表达非平行性下调(β1亚基下调更为显著)。 相似文献
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目的本研究观察雄激素缺乏对大鼠肠系膜小动脉舒缩功能的影响,以及其是否涉及Rho/Rho激酶(ROCK)信号通路。方法用离体血管张力法检测24周龄对照和去势大鼠的肠系膜小动脉收缩和舒张反应。结果 1)去势组大鼠的肠系膜小动脉对苯肾上腺素(PE)收缩反应较对照组无差异;2)去势组与对照组比较对低浓度(0.01μM)的乙酰胆碱(ACh)、硝普钠(SNP)舒张反应增强(23%±5%vs.5%±3%,28%±7%vs.9%±3%,respectively,P〈0.05),高度浓度时(10μM)无差别;3)预孵育ROCK抑制剂(Y-27632,1μM)后,较抑制前对照组对PE收缩反应降低(Emax99%±4%vs134%±8%,P〈0.01),去势组未有改变;两组对ACh反应较抑制前均无差异,两组对浓度依赖的Y-27632舒张反应也无差异。结论去势不影响大鼠肠系膜小动脉的收缩功能,但减弱了其对ROCK的敏感性;去势可增强大鼠肠系膜动脉的内皮和非内皮依赖性舒张,与ROCK无关。 相似文献
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McGuane JT Debrah JE Sautina L Jarajapu YP Novak J Rubin JP Grant MB Segal M Conrad KP 《Endocrinology》2011,152(7):2786-2796
The peptide hormone relaxin is a potent vasodilator with therapeutic potential in diseases complicated by vasoconstriction, including heart failure. However, the molecular mediators and magnitude of vasodilation may vary according to duration of exposure and artery type. The objective of these studies was to determine mechanisms of rapid (within minutes) relaxin-induced vasodilation and to examine whether relaxin dilates arteries from different animal species and vascular beds. Rat and mouse small renal, rat mesenteric, and human sc arteries were isolated, mounted in a pressure arteriograph, and treated with recombinant human relaxin (rhRLX; 1-100 ng/ml) after preconstriction with phenylephrine. Rat and mouse small renal as well as human sc arteries dilated in response to rhRLX, whereas rat mesenteric arteries did not. Endothelial removal or pretreatment with l-N(G)-monomethyl arginine (L-NMMA) abolished rapid relaxin-induced vasodilation; phosphatidylinositol-3-kinase (PI3K) inhibitors also prevented it. In cultured human endothelial cells, rhRLX stimulated nitric oxide (assessed using 4-amino-5-methylamino-2'7'-difluorofluorescein) as well as Akt and endothelial NO synthase (eNOS) phosphorylation by Western blotting but not increases in intracellular calcium (evaluated by fura-2). NO production was attenuated by inhibition of Gα(i/o) and Akt (using pertussis toxin and the allosteric inhibitor MK-2206, respectively), PI3K, and NOS. Finally, the dilatory effect of rhRLX in rat small renal arteries was unexpectedly potentiated, rather than inhibited, by pretreatment with the vascular endothelial growth factor receptor inhibitor SU5416. We conclude that relaxin rapidly dilates select arteries across a range of species. The mechanism appears to involve endothelial Gα(i/o) protein coupling to PI3K, Akt, and eNOS but not vascular endothelial growth factor receptor transactivation or increased calcium. 相似文献
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肺栓塞大鼠肺动脉和右心室HIF-1α的表达 总被引:1,自引:1,他引:0
目的观察肺栓塞大鼠肺细小动脉和右心室HIF-1α的表达,并探讨其在疾病发展过程中的作用。方法大鼠,体外制备栓子,经颈静脉注入栓子,两周后同法进行二次栓塞。测定平均肺动脉压(mPAP);心肺组织:(1)测定肺动脉相对中膜厚度(PAMT)和管壁面积/管总面积(WA/TA)及右心室肥大指数(RVHI);(2)分别用原位杂交方法和免疫组化方法检测肺动脉和右心室HIF-1α mRAN和HIF-1α蛋白的表达。结果(1)mPAP从4周组开始持续明显升高(P均〈0.01);PAMT和WA/TA在栓塞8周组开始升高(P均〈0.05);RVHI在12周组明显高于对照组(P〈0.01)。(2)肺动脉和右心室HIF-1α mPAN2周组开始升高(P均〈0.01);肺动脉HIF-1α蛋白3天组开始升高(P均〈0.01),右心室HIF-1α蛋白1周开始升高(P均〈0.01)。(3)相关关系:肺动脉HIF-1α mRAN和HIF-1α蛋白均与mPAP、PAMT和WA/TA呈正相关关系;右心室HIF-1α mRAN和HIF-1α蛋白均与mPAP和RVHI呈正相关关系。结论HIF-1α在肺动脉和右心室表达明显增高并与肺动脉高压,肺动脉重构的病理生理过程有明显相关关系。 相似文献
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Picchi A Gao X Belmadani S Potter BJ Focardi M Chilian WM Zhang C 《Circulation research》2006,99(1):69-77
Inflammation is a condition that underscores many cardiovascular pathologies including endothelial dysfunction, but no link is yet established between the vascular pathology of the metabolic syndrome with a particular inflammatory cytokine. We hypothesized that impairments in coronary endothelial function in the obese condition the prediabetic metabolic syndrome is caused by TNF-alpha overexpression. To test this, we measured endothelium-dependent (acetylcholine) and -independent vasodilation (sodium nitroprusside) of isolated, pressurized coronary small arteries from lean control and Zucker obese fatty (ZOF, a model of prediabetic metabolic syndrome) rats. In ZOF rats, dilation to ACh was blunted compared with lean rats, but sodium nitroprusside-induced dilation was comparable. Superoxide (O2*-) generation was elevated in vessels from ZOF rats compared with lean rats, and administration of the O2*- scavenger TEMPOL, NAD(P)H oxidase inhibitor (apocynin), or anti-TNF-alpha restored endothelium-dependent dilation in the ZOF rats. Real-time PCR and Western blotting revealed that mRNA and protein of TNF-alpha were higher in ZOF rats than that in lean rats, whereas eNOS protein levels were reduced in the ZOF versus lean rats. Immunostaining showed that TNF-alpha in ZOF rat heart is localized in endothelial cells and vascular smooth muscle cells. Expression of NAD(P)H subunits p22 and p40-phox were elevated in ZOF compared with lean animals. Administration of TNF-alpha more than 3 days also induced expression of these NAD(P)H subunits and abrogated endothelium-dependent dilation. In conclusion, the results demonstrate the endothelial dysfunction occurring in the metabolic syndrome is the result of effects of the inflammatory cytokine TNF-alpha and subsequent production of O2*-. 相似文献
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Although insulin-mediated vasodilation is impaired in insulin resistance, the mechanisms of this are unknown. We investigated factors mediating vasoactive responses to insulin in control and insulin-resistant rats. Responses to insulin in small mesenteric arteries from control and insulin-resistant rats were investigated after blocking endothelin-A receptors, cyclooxygenase, nitric oxide synthase, and potassium channels. In addition, insulin's effect on prostacyclin production in small mesenteric blood vessels was assessed by enzyme immunoassay. Insulin induced a concentration-dependent vasodilation in control arteries that was absent in arteries from insulin-resistant rats. However, in the presence of BQ610, an endothelin-A receptor antagonist, the response to insulin was normalized in insulin-resistant arteries. In control arteries, insulin-induced vasodilation was completely inhibited by indomethacin, meclofenamate, glibenclamide, or potassium chloride. In contrast, neither n-nitro-L-arginine nor the combination of charybdotoxin and apamin altered vasodilation to insulin. In insulin-resistant arteries in the presence of BQ610, vasodilation was also inhibited by indomethacin, glibenclamide, and potassium chloride. Insulin increased prostacyclin production in small mesenteric blood vessels from both groups of rats to a similar degree. Insulin-induced vasodilation in small rat mesenteric arteries is mediated through prostacyclin- and ATP-dependent potassium channels. However, insulin-resistant arteries do not vasodilate to insulin unless endothelin-A receptors are blocked. Thus, impaired relaxation to insulin in insulin-resistant rats is due to enhanced vasoconstriction by endothelin, which offsets a normal vasodilatory response to insulin. 相似文献
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目的:探讨模拟失重对体外培养的大鼠心肌细胞凋亡的影响。方法: 以原代培养的乳鼠心肌细胞为研究对象,以细胞回转器模拟失重效应,通过流式细胞检测技术观察模拟失重96 h对心肌细胞凋亡率的影响,进一步通过RT-PCR的方法,检测模拟失重96 h后,心肌细胞凋亡相关基因p53、bcl-2和caspase-3 mRNA表达的影响。结果: 模拟失重96 h可显著增高心肌细胞的凋亡率(P<0.05),与对照组相比,回转器模拟失重可显著增高促凋亡基因p53、caspase-3 mRNA的表达(P<0.05),而抑凋亡基因bcl-2 mRNA则表达显著减低(P<0.05)。结论: 回转器模拟失重96 h致心肌细胞凋亡表达增高,其可能机制是凋亡相关基因表达失衡有关。 相似文献
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ATP-sensitive K+ channels (KATP) couple intermediary metabolism to cellular activity, and may play a role in the autoregulation of vascular tones. Such a regulation requires cellular mechanisms for sensing O2, CO2, and pH. Our recent studies have shown that the pancreatic KATP isoform (Kir6.2/SUR1) is regulated by CO2/pH. To identify the vascular KATP isoform(s) and elucidate its response to hypercapnic acidosis, we performed these studies on vascular smooth myocytes (VSMs). Whole-cell and single-channel currents were studied on VSMs acutely dissociated from mesenteric arteries and HEK293 cells expressing Kir6.1/SUR2B. Hypercapnic acidosis activated an inward rectifier current that was K+-selective and sensitive to levcromakalim and glibenclamide with unitary conductance of approximately 35pS. The maximal activation occurred at pH 6.5 to 6.8, and the current was inhibited at pH 6.2 to 5.9. The cloned Kir6.1/SUR2B channel responded to hypercapnia and intracellular acidification in an almost identical pattern to the VSM current. In situ hybridization histochemistry revealed expression of Kir6.1/SUR2B mRNAs in mesenteric arteries. Hypercapnia produced vasodilation of the isolated and perfused mesenteric arteries. Pharmacological interference of the KATP channels greatly eliminated the hypercapnic vasodilation. These results thus indicate that the Kir6.1/SUR2B channel is a critical player in the regulation of vascular tones during hypercapnic acidosis. 相似文献
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目的 研究尾加压素Ⅱ(U Ⅱ)蛋白和mRNA及U Ⅱ受体(UT)mRNA在慢性栓塞性肺动脉高压大鼠肺动脉的表达,探讨其在病程中的作用.方法 雄性Wistar大鼠,麻醉后经颈静脉注入体外制备的血栓栓子,2周后同法进行2次栓塞,造模成功大鼠分为2周组、4周组、8周组、12周组,全程腹腔注射抗纤维溶解剂氨甲环酸,达到目标日期后行以下检查:(1)测量平均肺动脉压(mPAP);(2)用免疫学检验和原位杂交的方法检测不同节段肺动脉U Ⅱ蛋白和mRNA表达及UT mRNA表达;(3)在光镜下观察肺动脉显微结构的变化,测定肺动脉相对中膜厚度(PAMT)和管壁面积/管总面积(WA/TA).采用SPSS 13.0软件,所有数据以-x±s表示,组间比较采用单因素方差分析,组间差异采用LSD方差分析.结果 (1)栓塞后4、8及12周组的大鼠mPAP值分别为(19.9±6.2)mm Hg(1 mm Hg=0.133 kPa)、(23.8±4.1)mm Hg、(27.4±5.4)mm Hg,较对照组明显升高(F值为13.75,P<0.01),PAMT百分比分别为42.6±11.16、47.82±10.02、53.79±10.41,WA/TA百分比分别为22.75±6.79、25.32±4.90、27.05±7.71,较对照组均明显增大(F值分别为5.52和6.61,P均<0.01);(2)栓塞后肺动脉U Ⅱ蛋白和U Ⅱ mRNA以及UT mRNA表达上调,细小动脉较中型动脉变化更为明显,4、8及12周组肺细小动脉U Ⅱ mRNA和UT mRNA及U Ⅱ蛋白平均吸光度值分别为0.138±0.019、0.144±0.022、0.173±0.021和0.126±0.028、0.146±0.029、0.157±0.025,与对照组相比明显升高(F值分别为30.39、30.78和14.49,P均<0.01),随着栓塞时间的延长,表达呈明显增加的趋势;(3)肺细小动脉U Ⅱ蛋白和mRNA及UT mRNA的平均吸光度值均与mPAP、PAMT呈正相关关系(r值分别为0.822、0.866、0.846;0.675、0.712、0.756,P均<0.01).结论 慢性栓塞性肺动脉高压大鼠出现明显肺动脉重构,尾加压素Ⅱ蛋白和mRNA及其UT mRNA在肺动脉表达明显上调,其动态变化与肺动脉高压、肺血管重构的病理过程明显相关. 相似文献