减阻剂改善自发性高血压大鼠主动脉重塑

目的减阻剂(DRP)是一种可以减少流体阻力、增加流体剪切应力的线性高分子化合物,本实验观察静脉应用DRP对自发性高血压大鼠(SHR)主动脉重塑的影响。方法 24只8周龄雄性SHR随机分为3组:SHR+生理盐水组(SHR+NS组)、SHR+10 mg/L DRP组、SHR+20 mg/L DRP组,隔日给予静脉注射NS或不同剂量的DRP;8只年龄匹配的雄性Wistar大鼠(WR)作为对照组(WR+NS组),给予静脉注射NS。实验开始前及每20天记录大鼠体重、尾动脉收缩压、心率。60天后大鼠麻醉后心脏取血,酶联免疫吸附测定法检测大鼠血清内皮素(ET)水平。处死大鼠,分离大鼠升主动脉,石蜡包埋,HE染色观察主动脉形态结构,免疫组织化学法检测主动脉内皮素1(ET-1)表达。结果 SHR各组间体重、心率无显著差异。SHR+20 mg/L DRP组血压较SHR+NS组明显降低(P0.05),而SHR+10 mg/L DRP组与SHR+NS组血压无统计学差异。与SHR+NS组相比,SHR+10mg/L DRP组及SHR+20 mg/L DRP组血清ET水平显著降低,差异具有统计学意义。主动脉HE染色显示,与WR+NS组相比,SHR+NS组主动脉中膜厚度明显增厚(P0.05);静脉应用DRP后,与SHR+NS组相比,SHR+10mg/L DRP组、SHR+20 mg/L DRP组主动脉中膜厚度均显著降低(P0.05);SHR+10 mg/L DRP组、SHR+20mg/L DRP组与WR+NS组之间主动脉中膜厚度无统计学差异。主动脉免疫组织化学染色显示,ET-1在血管内皮及中层平滑肌均有表达,SHR大鼠主动脉表达明显高于WR大鼠;经静脉应用DRP后,SHR+10 mg/L DRP组、SHR+20 mg/L DRP组主动脉ET-1较SHR+NS组显著降低,SHR+10 mg/L DRP组与SHR+20 mg/L DRP组之间主动脉ET-1无显著差异。结论静脉应用DRP可改善SHR主动脉重塑,其机制可能与DRP通过增加主动脉内血液剪切应力抑制了ET-1表达有关,减阻剂可能为治疗高血压引起的主动脉重塑提供新的思路。     

miRNA-195、贝那普利与自发性高血压大鼠主动脉重构

目的　观察自发性高血压大鼠（SHR）的主动脉形态结构及其表达miRNA-195水平的变化,以及贝那普利干预对其影响。方法　8周龄雄性SHR及Wistar大鼠,随机分为SHR对照组、SHR贝那普利组（SHR干预组）、Wistar对照组、Wistar贝那普利组（Wistar干预组）,SHR干预组和Wistar干预组大鼠予贝那普利10　mg/（kg·d）干预,8周后,测定各组大鼠尾动脉血压,HE染色检测大鼠主动脉结构形态,实时荧光定量PCR检测大鼠主动脉miRNA-195表达,Western　blot检测大鼠主动脉转化生长因子β1（TGF-β1）、Smad3蛋白、Ⅰ型胶原（COL-Ⅰ）和Ⅲ型胶原（COL-　Ⅲ）蛋白表达水平。结果　贝那普利干预8周后,SHR干预组大鼠尾动脉收缩压及舒张压均显著低于SHR对照组（P<0.01）,高于Wistar对照组（P<0.01）。SHR干预组大鼠主动脉miRNA-195表达高于SHR对照组、Wistar干预组及Wistar对照组（P<0.05或P<0.01）;SHR干预组大鼠主动脉TGF-β1和Smad3蛋白表达低于SHR对照组（P<0.05）,但高于Wistar干预组（P<0.01）;SHR干预组大鼠主动脉COL-Ⅰ和COL-Ⅲ表达低于SHR对照组（P<0.05或P<0.01）,但高于Wistar干预组（P<0.01）;SHR干预组大鼠主动脉内中膜结构较SHR对照组改善,但未能恢复到Wistar对照组水平。结论　贝那普利干预可改善SHR主动脉重构,这一作用可能与miRNA-195抑制TGF-β1/Smad3信号通路有关。     

通心络对高血压大鼠血管内皮功能的保护作用研究

目的 探讨通心络对高血压大鼠血管内皮的保护作用.方法 实验动物分为3组,分别为自发性高血压大鼠组(SHR组),SHR服用通心络组(TXL组)和正常血压大鼠组(WKY组).通过放射免疫及聚合酶链反应检测主动脉一氧化氮(NO)、内皮素(ET)、血管内皮生长因子(VEGF)基因表达.结果 SHR组NO水平低于WKY组,TXL组NO水平高于SHR组.SHR组及TXL组mRNA表达均高于WKY组,以SHR组为最高.结论 通心络可能对高血压大鼠血管内皮功能有保护作用.     

通心络对高血压大鼠血管内皮功能的保护作用

目的探讨通心络对高血压大鼠血管内皮的保护作用。方法实验动物分为3组,分别为自发性高血压大鼠组(SHR组),SHR服用通心络组(TXL组)和正常血压大鼠组(WKY组)。通过放射免疫及聚合酶链反应检测主动脉一氧化氮(NO)、内皮素(ET)、血管内皮生长因子(VEGF)基因表达。结果SHR组NO水平低于WKY组,TXL组NO水平高于SHR组。SHR组ET-1含量及mRNA均高于WKY组,TXL组ET-1含量及mRNA表达低于SHR组,SHR组及TXL组mRNA表达均高于WKY组,以SHR组为最高。结论通心络可能对高血压大鼠血管内皮功能有保护作用。     

AngⅡ/NLRP3炎性小体信号通路介导高血压大鼠血管老化的机制

目的 通过观察自发性高血压大鼠(SHR)与对照组大鼠血管紧张素(Ang)Ⅱ/核苷酸结合寡聚结构域样受体蛋白(NLRP)3炎性小体信号通路指标的不同表达，探讨高血压(HTN)对血管老化(VA)影响的可能机制。方法 实验分为Wistar对照组(4周龄)、SHR模型组(12周龄)和WKY对照组(12周龄),体质量180～200 g,正常饲料喂食，持续8 w。尾袖法记录血压；胸主动脉和主动脉弓取材，进行苏木素-伊红(HE)和Masson染色，光镜下观察主动脉病理形态和血管胶原纤维变化；取胸主动脉进行Ca²⁺/Mg²⁺ ATP、Na⁺/K⁺ ATP的酶活性检测；Western印迹检测各组血管组织AngⅡ、NLRP3、平滑肌(SM)22α、基质金属蛋白酶(MMP)-9、MMP抑制因子(TIMP)-1、质膜Ca²⁺-ATP酶(PMCA)3的蛋白表达。结果 HE和Masson染色显示，Wistar对照组胸主动脉及主动脉弓外膜结构清楚，中膜平滑肌细胞排列规整，内膜较薄；WKY对照组胸主动脉及主动...     

AT1R shRNA重组腺病毒载体对SHR主动脉AT1R蛋白分布的影响

目的 利用靶向大鼠血管紧张素Ⅱ1型受体(AT1R)基因mRNA的短发夹RNA(shRNA)腺病毒载体,研究对在体自发性高血压大鼠(SHR)主动脉AT1R蛋白分布的影响.方法 重组腺病毒载体通过尾静脉注射法转染SHR,免疫组织化学法测定SHR主动脉AT1R表达.结果 AT1R的shRNA的重组腺病毒载体转染SHR,通过免疫组织化学法证实,大鼠主动脉的AT1R表达明显降低.结论 利用靶向大鼠AT1R 基因mRNA腺病毒载体,在体内环境下可以高效特异性抑制主动脉AT1R表达.     

缬沙坦对自发性高血压大鼠血管中血管紧张素转化酶2 mRNA表达的影响

目的:观察血管紧张素转化酶2(ACE2)在自发性高血压大鼠(SHR)血管中的表达以及缬沙坦对ACE2mRNA表达的影响。方法:24只12周龄雄性SHR随机分为SHR组和缬沙坦组,每组各12只,另设12只同龄雄性血压正常的Wistar大鼠作为对照组。缬沙坦组大鼠给予缬沙坦30mg.kg-1.d-1灌胃,SHR组及对照组给予等量0.9%氯化钠溶液灌胃。10周后,截取胸主动脉,光镜观察血管的病理变化,测定中膜厚度与血管腔内径之比;采用RT-PCR和免疫组织化学法检测胸主动脉中ACE2的表达。结果:与对照组比较,SHR组血管壁明显增厚,管腔变窄,且血管中ACE2mRNA和蛋白的表达均下调;而缬沙坦组ACE2mRNA和蛋白的表达明显高于SHR组。结论:高血压时血管重构可能与ACE2的表达下调有关,缬沙坦可能通过增加血管中ACE2的表达而发挥保护血管的作用。     

盐酸埃他卡林的降压作用及对高血压血管重构的影响

目的在自发性高血压大鼠(spontaneously hypertensive rat, SHR)上,评价盐酸埃他卡林(Iptakalim hydrochloride,Ipt)对高血压血管重构的实验治疗学作用.方法 21只12周龄SHR随机分为3组Ipt 3 mg/kg治疗组,赖诺普利(lisinopril, Lis)12 mg/kg治疗组和空白对照组.另设同月龄正常血压Wistar大鼠为正常对照组.大鼠ig Ipt、Lis或蒸馏水10 ml/kg,每日1次,连续4周,观察药物对高血压血管重构的影响.结果实验期4周内,SHR对照组血压和心率持续性进行性增高.其主动脉中层壁显著增厚,中层壁厚与内径的比值(M/L)也显著增大;肠系膜动脉的中层壁显著增厚,内径显著变小,二者的比值显著增大,表明高血压时动脉的结构发生了重构.Ipt能有效控制SHR的血压,降压效果确切,且可抑制SHR心率加快的趋势;Ipt治疗可阻止肠系膜动脉和主动脉的结构重构.相同实验条件下,Lis也均能有效控制SHR的血压,降压效果确切,对心率无明显影响;Lis治疗也可阻止肠系膜动脉和主动脉的结构重构.结论 Ipt能有效地控制SHR的血压,可以阻止高血压血管结构重构.     

阿托伐他汀对自发性高血压大鼠主动脉活性氧、AT1受体和p22phox表达的影响

目的探讨自发性高血压大鼠(SHR)主动脉活性氧(ROS)、AT1受体和p22phox mRNA表达的相关性及阿托伐他汀治疗对其影响.方法以正常血压大鼠为对照,观察SHR给予阿托伐他汀50 mg*kg-1*d-1灌胃30 d后,血压、血浆血管紧张素Ⅱ(AngⅡ)、血清一氧化氮(NO)、主动脉ROS含量、AT1受体蛋白和mRNA以及p22phox mRNA表达的变化.结果阿托伐他汀治疗30 d后,SHR血压、血浆AngⅡ、主动脉ROS含量、AT1受体蛋白和mRNA及p22phox mRNA表达下降,血清NO水平上升.多元逐步回归分析显示AT1受体为血管ROS的主要影响因素.结论血管AT1受体mRNA表达增加引起p22phox亚单位表达上调,导致ROS合成增加是高血压血管ROS增多的重要机制.阿托伐他汀可下调血管AT1受体和p22phox亚单位表达,减少ROS,减轻血管内皮功能受损.     

高血压患者血清microRNA-92a水平与大动脉僵硬度的关系

目的观察高血压患者血清micro RNA-92a(mi R-92a)水平及其与大动脉僵硬度的关系。方法入选113例高血压患者与54例健康体检者,采用实时荧光定量PCR(quantitative real-time PCR)技术检测血清中mi R-92a水平,采用酶联免疫吸附测定(ELISA)法测定血清中血清内皮素-1(endothelin-1,ET-1)水平,采用硝酸还原酶法测定血清中一氧化氮(nitric oxide,NO)含量,采用动脉硬化自动测量仪测量肱踝动脉脉搏波传导速度(brachial-ankle pulse wave velocity,ba PWV)。18-20周的SHR大鼠(WKY做对照组),适应环境1周后测定鼠尾动脉血压,采用Western Blot、Real time–PCR分析及测定主动脉内皮细胞mi R-92a、ET-1水平及e NOS含量。取大鼠主动脉组织行石蜡包埋、切片、HE染色及Masson染色,观察动脉中层结构改变及胶原纤维含量的变化。结果高血压患者血清mi R-92a、ET-1水平显著升高,血清NO含量明显降低,ba PWV明显增加(P值均0.001)。采用Spearman相关性分析发现mi R-92a与血清ET-1水平(相关系数0.74)及ba PWV(相关系数0.68)呈显著正相关,而与血清NO含量呈显著负相关(相关系数0.77)。SHR大鼠血压明显升高,与WKY相比有显著性差异(P值均0.0001)。Real time-PCR结果提示SHR大鼠主动脉内皮细胞mi R-92a及ET-1表达明显增加;e NOS的表达明显减少(P值均0.05);Western Blot分析SHR大鼠主动脉组织中ET-1表达增加,而phospho-e NOS(S1177)表达减少(P值均0.05)。主动脉HE染色及Masson染色可见SHR大鼠动脉平滑肌细胞增殖,中层增厚,胶原纤维含量明显增加。结论高血压患者血清mi R-92a水平升高,影响ET-1及e NOS的表达,导致动脉中层纤维含量大量增加,大动脉僵硬度显著增加。     

络活喜对自发性高血压大鼠血管壁重塑的实验研究

目的探讨络活喜(amlodipine)对自发性高血压大鼠(spontaneously hypertensive rats,SHR)血管壁重塑生物学机制。方法将10周龄雄性24只SHR随机分成3组,每组8只。对照组(SHRC)不作治疗,并与同周龄Wistar鼠组(n=8)作比较。生理盐水组(SHRNS),络活喜组(SHRA)分别经生理盐水、络活喜治疗8周后光镜观察血管几何形态,采用原位杂交及半定量RT-PCR方法检测ET-1(endothelin-1)、MMP-2(matrix metal-loproteinase-2)表达水平。结果对照组,生理盐水组血压明显增高,管腔增大,管壁明显增厚(P<0.05),尤以血管中层平滑肌细胞(vascular smooth cell,VSMC)肥大为主(P<0.01);ET-1,MMP-2表达显著增加(P<0.05)。治疗8周后,络活喜组血压明显降低,管壁变薄;ET-1、MMP-2表达减少(P<0.05)。结论络活喜可能通过抑制血管壁ET-1与MMP-2表达,遏制自发性高血压大鼠血管壁重塑。     

依达拉奉对大鼠心肌再灌注抗凋亡作用的机制

目的：观察大鼠心肌缺血再灌注时依达拉奉抗凋亡作用的机制。方法：采用体外结扎大鼠左前降支制备大鼠心肌缺血再灌注模型。将Wistar大鼠随机分为对照组、缺血再灌注组、依达拉奉组（再灌注即刻经尾静脉注射依达拉奉3mg／kg）。分别用TUNEL染色法及免疫组化法检测心肌细胞凋亡、心肌凋亡蛋白Bcl-2、Bax的表达。结果：（1）凋亡检测结果示,对照组无细胞凋亡,依达拉奉组较缺血再灌注组凋亡细胞数明品减少[（13．11±1．58）比（24．33±1．38）,P〈0．01];（2）免疫组化结果示,依达拉奉组与缺血再灌注组Bcl-2、Bax蛋白表达均明显高于对照组（P〈0．01）;依达拉奉组较缺血再灌注组Bcl-2蛋白表达明显升高[（0．2300±0．0218）比（0．0924±0．0152）],而Bax蛋白表达明显降低[（0．0249±0．0042）比（O．1312±0．0173）],P均〈0．01;缺血再灌注组Bcl-2／Bax比值较对照组明显降低[（0．6906±0．0035）比（1．1632±0．0212）],依达拉奉组Bcl-2／Bax比值（7．4752±0．5573）较缺血再灌注组和对照组明显升高（P〈0．01）。结论：依达拉奉能够减少心肌细胞凋亡,心肌细胞凋亡的减轻与下调Bax蛋白表达,上调Bcl-2蛋白表达以及Bcl-2／Bax比值有关。     

腺相关病毒介导的转人C－反应蛋白基因诱导大鼠高血压形成

目的研究过度表达人C-反应蛋白（hCRP）对大鼠血压的影响及其相关机制。方法以重组腺相关病毒为载体，介导hCRP基因（CRP组）或对照基因（GFP组）在大鼠体内表达，观察实验动物血压变化，并以westernblot方法检测大鼠主动脉血管紧张素l型受体（AT1），血管紧张素2型受体（AT2）的表达。结果CRP组大鼠血压从基因注射后2月开始升高，升高血压的效应在基因导入3月后保持稳定（与对照组相比约升高21mmHg）并持续到实验结束。而GFP组血压无明显变化。Western blot结果显示，与对照组相比，CRP组大鼠主动脉AT1蛋白水平升高，而AT2蛋白水平降低。结论重组腺相关病毒介导的hCRP过表达可以导致大鼠血压升高，其机制与增加主动脉AT1表达，降低AT2表达有关。     

一氧化氮对自发性高血压大鼠血管内皮功能的作用

目的　探讨自发性高血压大鼠 (SHR)内皮舒张功能不全的发生机制。方法　采用体外灌注的方法测定大鼠胸主动脉环对不同浓度乙酰胆碱的舒张反应变化 ,并测定血清中NO-3浓度和动脉组织中环鸟苷酸水平。结果　与魏 凯二氏大鼠 (WKY)比较 ,SHR胸主动脉环对乙酰胆碱的舒张反应明显减弱。左旋硝基精氨酸 (L NNA)可明显抑制大鼠胸主动脉环对乙酰胆碱的舒张反应 ,但并不能消除SHR和WKY对乙酰胆碱舒张反应之间的差异。与WKY比较 ,SHR血中NO-3水平明显降低 (P<0 .0 1) ,动脉组织中环鸟苷酸含量降低 (P<0 .0 1)。结论　SHR内皮依赖的血管舒张功能减低 ;一氧化氮 (NO)的生成或释放不足可能直接参与了SHR血管内皮依赖的舒张功能不全。     

Polyphenol-containing azuki bean (Vigna angularis) extract attenuates blood pressure elevation and modulates nitric oxide synthase and caveolin-1 expressions in rats with hypertension

Background and aimsAzuki beans (Vigna angularis) contain polyphenols such as proanthocyanidins that exhibit potential radical scavenging activities. We herein investigated the effects of polyphenol-containing azuki bean extract (ABE) on elevated blood pressure, nitric oxide (NO) production, and expressions of endothelial NO synthase (eNOS), inducible NOS (iNOS), and caveolin-1 proteins in the aorta and kidney of chronically hypertensive rats.Methods and resultsSpontaneously hypertensive rats (SHRs/Izm) with approximately 200 mm Hg systolic blood pressure (SBP) were randomly divided into 2 groups fed either 0% or 0.9% ABE-containing diet. Age-matched normotensive Wistar–Kyoto rats were used as the control. The content of 24-h urinary nitrate/nitrite (NOx) excretion was measured to evaluate NO production. After 8 weeks of treatment, the eNOS, iNOS, and caveolin-1 protein expressions in the aorta and kidney were analyzed by western blotting. The SBP of the ABE-treated SHR was significantly lower than that of the untreated SHR. The level of 24-h urinary NOx excretion was significantly higher in the ABE-treated SHR than in the untreated SHR. The eNOS and iNOS expressions in the aorta and kidney were remarkably upregulated in the untreated SHR but suppressed in the ABE-treated SHR. The vascular and renal caveolin-1 expressions were upregulated in the ABE-treated SHR.ConclusionsABE reduced the elevated blood pressure and increased NO production in long-term treatment. It may be associated with the modulation of eNOS and iNOS protein expressions in the aorta and kidney during the development of hypertension.     

血压平对自发性高血压大鼠血管重塑的作用

目的观察复方中药血压平对自发性高血压大鼠(SHR)血压、血清一氧化氮(NO)含量及动脉血管重塑的影响,并探讨其作用机制。方法将SHR30只随机分为5组,每组6只,分别为SHR对照组、血压平低剂量组、血压平中剂量组、血压平高剂量组、达爽对照组,另随机选6只WKY大鼠作为对照组。测定血压及血清中NO含量,解剖分离其主动脉,观察其形态,测定动脉管壁与腔径之比。结果血压平可降低SHR血压,升高血清NO含量,与SHR对照组相比有统计学意义(P<0.01),且与药物剂量相关;血压平高剂量组优于达爽对照组(P<0.05)。结论血压平有降压及逆转高血压大鼠血管重塑的作用。     

降压药物对高血压大鼠血管平滑肌细胞离子泵活性及分泌血管紧张素Ⅱ的影响

目的观察不同类型的降压药物对自发性高血压大鼠(SHR)动脉血管平滑肌细胞钠泵、钙泵活性及分泌血管紧张素Ⅱ(AngⅡ)的影响。方法采用组织块种植法培养大鼠胸主动脉血管平滑肌细胞24 h后,分为WKY大鼠组、SHR组、赖诺普利组、氨氯地平组、伊贝沙坦组、氢氯噻嗪组和美托洛尔组。分别用不同药物对SHR动脉血管平滑肌细胞进行干预。采用生化酶学方法、放射免疫分析法分别测定细胞膜离子泵活性和AngⅡ浓度。结果与WKY大鼠组比较,SHR组大鼠钠泵和钙泵活性明显降低(P<0.01),AngⅡ浓度明显升高(P<0.05);与SHR组比较,赖诺普利组、伊贝沙坦组钠泵和钙泵活性明显增高(P<0.05,P<0.01);氨氯地平组钠泵活性明显增高(P<0.01);氢氯噻嗪组和美托洛尔组钠泵、钙泵活性及AngⅡ浓度差异无统计学意义。与SHR组比较,赖诺普利组、氨氯地平组AngⅡ浓度明显降低(P<0.05),伊贝沙坦组AngⅡ浓度明显升高(P<0.05)。结论赖诺普利、伊贝沙坦和氨氯地平能提高SHR动脉血管平滑肌细胞膜离子泵活性,并影响其分泌AngⅡ。     

Reduction of plasma angiotensin II to normal levels by antisense oligodeoxynucleotides against liver angiotensinogen cannot completely attenuate vascular remodeling in spontaneously hypertensive rats

OBJECTIVE: The exact role of angiotensinogen (AGT) in vascular remodeling has yet to be determined. In the present study, we examined the effects of reducing plasma AGT by intravenous injections with antisense oligodeoxynucleotides (ODNs) against AGT targeted to the liver on vascular remodeling in spontaneously hypertensive rats (SHRs). DESIGN AND METHODS: The ODNs against rat AGT were coupled to asialoglycoprotein (ASOR) carrier molecules, which serve as an important method for regulating liver gene expression. Male SHRs (n = 18) and age-matched male Wistar- Kyoto (WKY) rats (n = 4) were used for this study. All animals were fed a standard rat diet throughout the experiment At 10 weeks of age, the SHRs were divided into three groups (n = 6); systolic blood pressure (SBP) was similar in each group. The control group received saline, the sense group was injected with the sense ODN complex and the antisense group was injected with the antisense ODN complex. WKY rats were fed for the same period of time. The ASOR-poly(L)lysine-ODN complex was injected into the tail veins twice a week. RESULTS: At the end of the treatment, a reduction in AGT mRNA levels in the liver and plasma AGT was observed only in the animals injected with antisense ODNs. Antisense ODNs significantly reduced the plasma angiotensin II (Ang II) concentrations to levels similar to those observed in WKY rats. Antisense ODNs significantly reduced the SBP (180.7 +/- 4.4 mmHg) and media cross-sectional areas of the aorta (1.11 +/- 0.02 mm2), which were still larger than those seen in WKY rats (140.3 +/- 2.1 mmHg, 0.84 +/- 0.02 mm2), compared with the SHRs injected with sense ODNs (225.2 +/- 4.4 mmHg, 1.24 +/- 0.02 mm2) and control SHRs (223.7 +/- 4.8 mmHg, 1.25 +/- 0.02 mm2). The aortic angiotensin-converting enzyme (ACE) activity and collagen concentrations, which were significantly higher than those seen in WKY rats, did not significantly change among the SHR groups. The aortic AGT, ACE, angiotensin II type 1 (AT1) receptor and angiotensin II type 2 (AT2) receptor mRNA also did not significantly change among the SHR groups. CONCLUSION: On the basis of these findings, plasma AGT is thus considered to play a role in the development of hypertrophy of smooth muscle in the aorta of SHRs, it is thought to have only a slight effect, however, on the remodeling of the matrix tissue when the suppression of hypertension is insufficient.     

Arterial structural changes with verapamil in spontaneously hypertensive rats.

Reducing pulse pressure might be more powerful than reducing mean arterial pressure to obtain regression of vascular hypertrophy. However, this hypothesis has never been investigated in the conduit arteries of intact hypertensive animals. A group of 4-week-old spontaneously hypertensive rats (SHR) was treated with the calcium-entry blocker verapamil (50 mg/kg) for 16 weeks and compared with untreated SHR and control Wistar Kyoto (WKY) normotensive rats of the same age. At the end of the experiment, intraarterial thoracic aorta blood pressure was measured both in the conscious and anesthetized animals. Carotid artery diameter and stiffness (echo-tracking techniques) and aortic histomorphometry were determined in parallel. With verapamil, pulse pressure, but not mean arterial pressure, was significantly decreased but did not reach the normotensive values. Carotid internal diameter, medial thickness, and collagen content were significantly reduced by comparison with SHR and did not differ from the values of the WKY group. A significant positive and independent correlation was observed between pulse pressure and medial thickness in the overall population. The study shows that, in SHR chronically treated with verapamil, structural changes may be completely prevented without any change in mean arterial pressure. The parallel change in pulse pressure might suggest that mechanosensitive elements within the vascular wall may be selectively sensitive to the dynamic aspects of physical forces and are able to convert frequency and amplitude information into cellular responses that lead to vascular remodeling.