Effects of black cohosh on the plasminogen activator system in vascular smooth muscle cells

Objective

The rhizome of the Cimicifuga racemosa plant (commonly known as black cohosh) has been used for menopausal complaints. Studies regarding the cardiovascular effects of black cohosh are lacking. We investigated the effect of black cohosh on the plasminogen activator system in cultured vascular smooth muscle cells (VSMCs).

Methods

VSMCs were isolated from rat aortae. Expression of plasminogen activator inhibitor type 1 (PAI-1) and tissue-type plasminogen activator (t-PA) proteins were evaluated by Western blot analysis and enzyme-linked immunosorbent assay, respectively. The activities of PAI-1 and t-PA in the conditioned media were assessed by fibrin overlay zymography. A 40% 2-propanol extract of black cohosh was used.

Results

Black cohosh extract (BcEx) stimulated the protein expression of PAI-1, but it did not affect that of t-PA. Vitamin E, a potent antioxidant, inhibited the BcEx-induced increase in PAI-1 expression, while ICI 182,780, an estrogen receptor antagonist, had no effect. Fibrin overlay zymography revealed that BcEx increased the activity of PAI-1 in the conditioned media, while concurrently decreasing that of free t-PA by inducing a binding to PAI-1.

Conclusions

BcEx induces PAI-1 protein expression in the VSMCs likely via an oxidant mechanism. It also stimulates the enzyme activity of PAI-1 and reduces that of free t-PA. These findings suggest that black cohosh might exert a negative influence on fibrinolysis.     

Tissue plasminogen activator and plasminogen activator inhibitor-1 levels in patients with acute paraquat intoxication

To investigate the effects of reactive oxygen species (ROS) on tissue plasminogen activator (tPA) and plasminogen activator inhibitor-1 (PAI-1) plasma levels, and their possible implications on clinical outcome, we measured tPA and PAI-1 levels in 101 patients with acute paraquat (PQ) intoxication. The control group consisted of patients who ingested non-PQ pesticides during the same period. tPA and PAI-1 levels were higher in the PQ group than in the controls. PQ levels were significantly correlated with ingested amount, timelag to hospital, tPA level, and hospitalization duration. tPA levels were correlated with PAI-1, fibrin degradation product (FDP), and D-dimer. D-dimer levels were lower in the PQ group than in the controls. Univariate analysis indicated the following significant determinants of death: age, ingested amount, PQ level, timelag to hospital, serum creatinine, lipase, pH, pCO(2), HCO(3) (-), WBC, FDP, PAI-1, and tPA. However, multivariate analysis indicated that only PQ level was significant independent factor predicting death. In conclusion, tPA and PAI-1 levels were higher, while D-dimer levels were lower in the PQ group than in the controls, implying that ROS stimulate tPA and PAI-1, but PAI-1 activity overrides tPA activity in this setting. Decreased fibrinolytic activity appears to be one of the clinical characteristics of acute PQ intoxication.     

A simple method for differentiating vascular smooth muscle cells and fibroblasts in tissue culture

Summary The morphologic differentiation of vascular smooth muscle cells and fibroblasts in tissue culture is difficult if not impossible. By direct immunofluorescence, it is possible to distinguish between vascular smooth muscle cells and fibroblasts after 6 to 10 days in tissue culture. Microfilaments appear from the 6th to the 10th day. After an incubation period of 30 minutes with antibody against smooth muscle actomyosin at room temperature, microfilaments are demonstrable in smooth muscle cells. In contrast, fibroblasts, if incubated for the same period, show strong nuclear fluorescence and a primary fluorescence of the cytoplasm, but filaments are not visible. If fibroblasts are incubated with antiactomyosin for one hour at 37 °C, however, microfilaments are easily detectable.With this method it is possible to differentiate in a simple manner vascular smooth muscle cells from fibroblasts in a heterologous tissue culture.These studies were supported by the Deutsche Forschungsgemeinschaft, SFB 90,Cardiovasculäres System.     

缺氧内皮细胞培养液对肺动脉平滑肌细胞表型的影响

用细胞培养和形态定量分析方法观察缺氧对肺动脉平滑肌细胞表型的影响。结果显示，缺氧性内皮细胞条件培养液组肺动脉平滑肌细胞的二倍体细胞和α－ｓｍ－ａｃｔｉｎ含量均少于常氧性内皮细胞条件培养液组（Ｐ＜０．０５），尤以肌丝成份减少最明显；粗面内质网和线粒体却显著增多。而直接缺氧组与常氧组无明显差异。提示：缺氧可促使内皮细胞产生和释放某种促平滑肌细胞表型转化的物质或因子，从而改变了肺动脉管壁细胞之间的正常调控关系，导致平滑肌细胞肥大，合成细胞外基质增多。     

丹参对血管平滑肌细胞抑制内皮细胞分泌的纤溶酶原激活物活性的影响

培养的猪内皮细胞(EC)产生和分泌纤溶酶原激活物(PA),血管平滑肌细胞(SMC)的无血清条件培养液(SMC-CM)与EC的无血清条件培养液(EC-CM)混合后,后者的PA活力明显减弱。EC与SMC复合培养时,其产生的PA活力亦降低(降低70.7%)。以上结果提示SMC产生纤溶酶原激活物抑制剂PAI抑制了EC分泌的PA活性。SMC-CM经SDS-PAGE后作反向纤维蛋白自显影显示PAI的分子量范围在49,000—62,000,与Laug(1985)报道的相似(55,000)。我们研究了中药丹参(Radix Salviae Miltiorrhizae,RSM)对SMC分泌PAI活性的影响。结果表明,培养的SMC经丹参作用后,其CM对尿激酶及内皮细胞产生的PA活性的中和作用明显减弱(P<0.05、P<0.01或P<0.001)。     

原花青素对同型半胱氨酸诱导的血管平滑肌细胞增殖、迁移的影响

目的： 探讨葡萄籽中的原花青素(GSP)对同型半胱氨酸(HCY)诱导的血管平滑肌细胞(VSMC)增殖、迁移的抑制作用及其机制。方法: 采用细胞计数及［3H］-TdR检测细胞增殖，用DCFH-DA、Western blotting法检测GSP对VSMC增殖、迁移的抑制作用及分析其相关的分子信号转导通路。结果: HCY浓度依赖性地诱导VSMC的增殖与迁移, 1 mmol/L HCY使VSMC的增殖与迁移分别比对照组升高3.9倍及4.1倍(P<0.01)；DCFH-DA结果显示, 1 mmol/L HCY使VSMC的活性氧(ROS)水平比对照组升高4倍(P<0.01)。而在不同浓度的GSP(5-20 g/L) 处理组，HCY诱导VSMC的增殖、迁移以及活性氧水平都被显著抑制(P<0.01)。在GSP 20 g/L 处理组，VSMC的增殖、迁移以及活性氧水平都接近空白对照组。与HCY组相比，GSP还显著降低HCY诱导VSMC MCP-1、IL-6及TNF-α的表达水平(P<0.01)。GSP还阻断HCY诱导的NF-κB的激活及显著降低NF-κB的活性(P<0.01)。结论: GSP通过抑制NF-κB的激活而抑制HCY诱导的血管平滑肌细胞增殖、迁移及炎症反应。     

Length-tension relationships in resting and activated vascular smooth muscle fibres

Summary The length-tension relationships of resting or activated (by 130 mM of potassium) helical strips of the pig coronary artery were studied. The distensibility of the preparations was expressed by approximated exponential function. In non-activated strips, an average lengthening of 9.64% was necessary for doubling the resting tension. The maximum of active tension (isometric contractions) occurred at high degrees of muscle stretch, whereas the maximum of shortening (isotonic free-loaded contractions) was found at lower values of resting tension. If the theory of the sliding mechanism is a correct assumption for the contraction process of vascular smooth muscle, the maximum of active tension observed at a muscle stretch of about 8000 dynes/mm² is obviously caused by an optimal overlapping of actin and myosin filaments. At this high degree of muscle stretch, however, a great number of cross-linkages is necessary to overcome the passive tension and only few cross-linkages are available for shortening. Therefore, in isotonic contractions the amount of shortening is diminished and the time to peak of contraction is augmented with elevated resting tension exceeding 1000 dynes/mm².     

同型半胱氨酸诱导血管平滑肌细胞组织因子表达增强

目的: 研究同型半胱氨酸（Hcy）诱导人血管平滑肌细胞（VSMCs）组织因子（TF）表达的作用，及其对核转录因子（NF-κB）活性和诱导型一氧化氮合酶（iNOS）表达的影响。 方法: 培养人脐动脉VSMCs，将不同浓度的Hcy和/或NF-κB抑制剂PDTC与VSMCs孵育不同时间，用RT-PCR方法检测TF mRNA表达，用Western blotting检测核NF-κB水平，用流式细胞术（FCM）检测细胞表面TF蛋白水平和iNOS水平。 结果: 10 μmol/L Hcy作用4 h，TF表达开始升高，500 μmol/L达峰值，Hcy能显著诱导VSMCs表达TF mRNA；对照组VSMCs细胞膜表面有低水平的TF蛋白表达，10 μmol/L Hcy作用4 h即可诱导VSMCs表达TF蛋白，500 μmol/L 达高峰，Hcy能显著诱导VSMCs表达TF；500 μmol/L Hcy作用1 h，细胞核NF-κB水平明显升高，Hcy可诱导VSMCs NF-κB活化;NF-κB抑制剂PDTC可明显抑制Hcy对TF mRNA和细胞TF表达的诱导作用；单独Hcy作用不能诱导VSMCs表达iNOS。 结论: Hcy能显著诱导VSMCs表达TF，增强VSMCs的NF-κB活化，从而介导TF基因表达和蛋白合成，通过NF-κB介导VSMCs表达TF可能是Hcy导致AS、血栓形成的重要机制。     

Alterations of excitation-contraction coupling by platelet-derived growth factor in enzymatically isolated and cultured vascular smooth muscle cells

We studied stimulus-specific alterations of the excitation-contraction coupling pathway in freshly isolated contractile and subcultured non-contractile vascular smooth muscle cells. Using the calcium indicator aequorin, we detected physiological increases in cytoplasmic free calcium ([Ca²⁺]_i) in subcultured smooth muscle cells subjected to angiotensin or 33 mM potassium depolarization. These increases were qualitatively identical to those previously measured in intact vascular strips. Platelet-derived growth factor (PDGF) induced a slow, sustained [Ca²⁺]_i increase when applied to the subcultured smooth muscle cells at low picomolar concentrations. Freshly isolated, contractile vascular smooth muscle cells, prepared by a novel technique, exhibited a slow shortening of 20% of resting length in response to PDGF. PDGF also markedly potentiated smooth muscle cell shortening in response to an ED₅₀ dose of phenylephrine. This effect was PDGF concentration dependent. The time course of shortening induced by PDGF alone was consistent with the time course of the PDGF-induced [Ca²⁺]_i increase in the cultured smooth muscle cells. These data suggest that agonists which induce [Ca²⁺]_i changes in contractile smooth muscle cells may retain this ability with respect to cultured smooth muscle cells. PDGF, a peptide mitogen for proliferative smooth muscle cells, may also serve to modulate vascular tone by modestly raising [Ca²⁺]_i in contractile smooth muscle cell and, therefore, sensitizing the cells to alpha adrenergic agonists.     

血管紧张素转换酶抑制剂抑制血管平滑肌细胞增殖的机制

目的: 探讨血管紧张素转换酶抑制剂(ACEI)抑制动脉平滑肌细胞增殖及向内膜迁徙的机理。方法: 球囊导管损伤Wistar大鼠颈总动脉, 实验组于术前2 d开始给与ACEI(temocapril-HCl 10 mg·kg^-1·d^-1), 术后2 d、3 d、5 d分批处死。用抗人PDGF-A、-B及其受体, 抗人MMP-1、MMP-9等抗体以ABC法行免疫染色。动脉组织行放射自显影乳剂原位酶谱分析。电镜下观察细胞质内小器官及细胞周围弹性、胶原纤维的密度。结果: 给ACEI后, PDGF及其受体、MMP-1、-9蛋白阳性细胞率及明胶酶活性显著降低, 并抑制了中膜平滑肌细胞的表型转换。结论: ACEI可能通过继发地抑制PDGFs、MMPs蛋白表达, 阻碍细胞表型转换, 从而阻止中膜平滑肌细胞增殖及向内膜迁徙。     

Induction of endothelin-1 expression by oxidative stress in vascular smooth muscle cells

Atherosclerosis is based on endothelial dysfunction leading to impaired vasomotor function. This is partially due to nitric oxide (NO) depletion caused by oxidative stress. Since the vasoconstrictor endothelin-1 (ET-1) might also be involved in endothelial dysfunction, we investigated whether oxidative stress regulates ET-1 expression in vascular smooth muscle cells (VSMC). Human aortic VSMC were treated with H₂O₂ (200 μM) for up to 8 h. mRNA expression of preproendothelin (prepro-ET) was analyzed by RT-PCR. ET-1 protein and the marker for oxidative stress, 8-isoprostane, were determined by ELISA. Activity of cytosolic phospholipase A2 (cPLA₂) as an indicator of ET-1 autocrine activity was measured photometrically. Stimulation of VSMC with H₂O₂ resulted in increased expression of prepro-ET mRNA after 1 h with a maximum after 6 h (fourfold), similar to treatment with angiotensin II. ET-1 protein was significantly increased by H₂O₂ treatment with a maximum after 8 h (P<.05). This effect was inhibited by the antioxidants resveratrol (100 μM) and quercetin (50 μM). In quiesced VSMC, incubation with H₂O₂-conditioned medium resulted in increased cPLA₂ activity compared to the controls (P<.05). This activity was partially inhibited by the ET_A-receptor antagonist, PD 142893 (10 μM), indicating functional ET-1 in the conditioned medium. The presence of oxidative stress in H₂O₂-treated VSMC was associated by significantly increased formation of 8-isoprostane (P<.05). The data indicate for the first time that oxidative stress increases ET-1 generation and autocrine ET-1 activity in VSMC, a mechanism that might contribute to endothelial dysfunction in atherosclerosis.     

人脐静脉内皮细胞分泌组织型纤溶酶原激活物及其抑制剂1对醒脑静干预的反应

背景：前期研究发现醒脑静能有效抑制兔心肌缺血再灌注模型的炎症递质及促纤溶作用,但是影响纤溶系统活性的作用机制未完全明确。目的：观察醒脑静对重组人肿瘤坏死因子α介导人脐静脉内皮细胞分泌组织型纤溶酶原激活物和纤溶酶原激活物抑制剂1及其基因表达的影响。方法：取3-5 代人脐静脉内皮细胞,在培养基中添加10 μg/L 重组人肿瘤坏死因子α介导人脐静脉内皮细胞分泌组织型纤溶酶原激活物和纤溶酶原激活物抑制剂1及其基因表达,醒脑静组加入不同浓度(5,10,20 mL/L)的醒脑静干预,阳性对照组添加氟伐他汀(1 μmol/L),并设立单纯人脐静脉内皮细胞培养的空白对照组。培育24 h后采用酶联免疫吸附双抗体夹心法(ELISA)检测细胞上清液组织型纤溶酶原激活物和纤溶酶原激活物抑制剂1水平;采用反转录聚合酶链反应检测人脐静脉内皮细胞的组织型纤溶酶原激活物和纤溶酶原激活物抑制剂1的mRNA表达。结果与结论：重组人肿瘤坏死因子α组纤溶酶原激活物抑制剂1分泌和mRNA表达较空白对照组显著升高 (P < 0.05),组织型纤溶酶原激活物分泌和mRNA表达较空白对照组显著降低(P < 0.05)。不同浓度醒脑静组纤溶酶原激活物抑制剂1分泌和mRNA表达均较重组人肿瘤坏死因子α组显著降低(P < 0.05),而组织型纤溶酶原激活物分泌和mRNA表达均较重组人肿瘤坏死因子α组显著升高(P < 0.05),且呈剂量依赖关系。结果证实,醒脑静作用可逆转重组人肿瘤坏死因子α所致的人脐静脉内皮细胞的纤溶活性。 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程全文链接：     

Isolation of vascular smooth muscle cells from a single murine aorta

The vascular smooth muscle cell plays a significant role in many important cardiovascular disorders, and smooth muscle biology is therefore important to cardiovascular research. The mouse is critical to basic cardiovascular research, largely because techniques for genetic manipulation are more fully developed in the mouse than in any othermammalian species. We describe here a technique for isolating smooth muscle cells from a single mouse aorta. This technique is particularly useful when material is limiting, as is frequently the case when genetically modified animals are being characterized.     

Relationship between plasminogen activator inhibitor type-1 (PAI-1) gene polymorphisms and osteoporosis in Turkish women

OBJECTIVE:

The development of osteoporosis is associated with several risk factors, such as genetic structures that affect bone turnover and bone mass. The impact of genetic structures on osteoporosis is not known. Plasminogen activator inhibitor type-1 regulates the bone matrix and bone balance. This study assessed the correlation between plasminogen activator inhibitor type-1 gene 4G/5G polymorphisms and osteoporosis in a population of Turkish women.

METHODS:

A total of 195 postmenopausal female patients who were diagnosed with osteoporosis (Group I) based on bone mineral density measurements via dual-energy x-ray absorptiometry and 90 females with no osteoporosis (Group II) were included in this study. Correlations between PAI-1 gene 4G/5G polymorphisms and osteoporosis were investigated through the identification of PAI-1 gene 4G/5G polymorphism genotypes using the polymerase chain reaction.

RESULTS:

No significant differences in the genotype and allele frequency of 4G/5G plasminogen activator inhibitor type-1 polymorphisms were observed between the two groups, and both groups exhibited the most frequently observed 4G5G genotype.

CONCLUSION:

No correlation between the development of osteoporosis in the female Turkish population and 4G/5G plasminogen activator inhibitor type-1 gene polymorphisms was observed.     

动脉粥样硬化斑块形成时血管平滑肌细胞增生相关基因的cDNA全长克隆及其功能的初步探讨

目的　克隆动脉粥样硬化斑块形成时血管平滑肌细胞（ＳＭＣ） 增生相关基因的ｃＤＮＡ 全长,并对其功能进行初步探讨。方法　选用氧化低密度脂蛋白（ｏｘＬＤＬ） 作为刺激物作用于培养的人主动脉ＳＭＣ,利用减除杂交技术构建减除文库,克隆相关基因片段,在全长文库构建的基础上筛选相关基因的ｃＤＮＡ全长。并进行原核系统内蛋白表达及量效关系检测。结果　发现了４ 个新基因片段,克隆了一个新基因ｃＤＮＡ 全长,该基因在原核系统内有大约相对分子质量为４４ ０００ 的蛋白表达,其高表达可能与ＳＭＣ增生有关。结论　筛选克隆的新基因ＰＳＭＣＨ１ 在动脉粥样硬化斑块形成时可能有较重要的生物学作用。     

Insulin enhances angiotensin II induced DNA synthesis in vascular smooth muscle cells of the rat

Summary Hypertension has a high prevalence among subjects with decreased insulin sensitivity and/or hyperinsulinemia. Furthermore, angiotensin II plays a pivotal role in the regulation of vascular tone and is known to induce hypertrophy and/or hyperplasia in vascular smooth muscle cells. In the present study, the effect of insulin on angiotensin II induced smooth muscle cell growth (Wistar-Kyoto rat) was investigated. Cell growth was assessed by the measurement of [³H]thymidine incorporation into cell DNA. Insulin in a concentration range of 1.7 × 10^–10–1.7 × 10^–6 M lacked any effect on cell DNA synthesis. However, insulin enhanced the angiotensin 11 induced DNA synthesis in a concentration-dependent manner. This effect was similar in cells with a weak and in cells with a marked response in DNA synthesis to stimulation with 100 nM angiotensin 11. In conclusion, insulin is able to enhance angiotensin 11 induced DNA synthesis and may therefore function as a growth cofactor in vascular smooth muscle cells.Abbreviations AngII angiotensin II - EGF epidermal growth factor - bFGF basic fibroblast growth factor - PDGF-BB platelet-derived growth factor-BB - VSMC vascular smooth muscle cells Dedicated to Prof. Dr. N. Zöllner on the occasion of his 70th birthday     

胰岛素和葡萄糖对缺氧血管内皮细胞分泌tPA和PAI-1抗原的影响

目的: 观察胰岛素和葡萄糖对缺氧血管内皮细胞分泌组织型纤溶酶原激活物(tPA)及其抑制物-1(PAI-1)的影响。 方法:培养人脐静脉内皮细胞株ECV-304。分组实验:(1)常氧组;(2)在缺氧条件下又分为Ⅰ:缺氧对照组;Ⅱ:低浓度组:胰岛素150 mU/L、葡萄糖5.5 mmol/L;Ⅲ:中浓度组:胰岛素450 mU/L、葡萄糖15 mmol/L;Ⅳ:高浓度组:胰岛素900 mU/L、葡萄糖30 mmol/L;Ⅴ:渗透压对照组:甘露醇24.5 mmol/L。取培养4、8、12 h 3个时点,用ELISA法测定细胞培养上清液tPA、PAI-1抗原。结果:缺氧明显增加tPA和PAI-1抗原分泌,tPA/PAI-1值明显增加(P＜0.01)。胰岛素和葡萄糖能够刺激缺氧内皮细胞分泌tPA和PAI-1抗原,在缺氧8 h以内,tPA/PAI-1比值明显增加(P＜0.05)。随缺氧时间的延长,tPA/PAI-1值逐渐下降。结论:胰岛素和葡萄糖能够刺激内皮细胞分泌tPA和PAI-1抗原,在缺氧8 h以内,tPA/PAI-1值升高,纤溶活性升高,有利于局部自发性纤溶的发生。此作用可能是IGK治疗急性心肌梗死的机制之一。     

牛磺酸减轻β-甘油磷酸诱导的大鼠血管平滑肌细胞钙化氧化应激在反流物所致食管粘膜损伤中的作用

目的：观察牛磺酸对钙化的形成及逆转作用的影响，探讨牛磺酸在血管钙化发生中的作用。方法：利用β-甘油磷酸制备钙化血管平滑肌细胞（VSMCs），测定细胞钙含量、碱性磷酸酶活性、[⁴⁵Ca]沉积及[³H]-胸腺嘧啶。结果：与对照组相比，钙化细胞的钙含量、ALP活性和[⁴⁵Ca]沉积均明显升高（P<0.05），而牛磺酸与β-甘油磷酸同时孵育呈剂量依赖性地抑制钙化发生。在牛磺酸逆转实验中，钙化细胞的钙含量、ALP活性和[⁴⁵Ca]沉积均较换液前明显降低（P<0.01）；且牛磺酸呈剂量依赖性地逆转已钙化细胞。与对照组相比，钙化细胞的细胞数量和[³H]-TdR掺入量增加（P<0.01），牛磺酸早期干预组显著抑制钙化细胞的增殖，但牛磺酸对已钙化的细胞,增殖抑制效应不明显。结论：牛磺酸可抑制细胞钙化形成且能逆转已形成钙化。     

Plastic properties of vertebrate smooth muscle (Taenia coli of the guinea pig)

Summary After extension and creep due to a constant load the taenia coli of the guinea pig shows plastic deformation. The deformation is partially abolished by complete unloading: to 51% in the relaxed and to 83% in the depolarized = contracted state. The quantitative relations between creep (N) and its time derivative (dN/dt) as well as those between stress relaxation (R) and dR/dt stated in our previous papers, remain valid if plastic deformations have occurred during these processes.     

不同前负荷条件下去神经平滑肌的应力松弛与膜电流特征

BACKGROUND: Muscle stretch test is a method for testing mechanical properties of denervated muscle under diverse loads. OBJECTIVE: To observe changes of spontaneous tension wave in myography and membrane electric current in aorta smooth muscle samples under several preload conditions. METHODS: Denervated intact smooth muscle samples were taken from the Kunming mouse aorta and urinary bladder wall. Smooth muscle samples were fixed on a micro positioning device and the first stretch was induced for a passive tension up to 1 g, this position was determined as the initial length (L0). Intermittently, with increasing sample length from L0 every 5 minutes, the 1st and 10th stretch were recorded as low- (L0+1) and high-preload (L0+10). 3% CaCl2 and 0.05% nitrendipine were dropped on the samples before L0+1 and L0+10 stretch were recorded. Membrane current changes were evaluated by glass microelectrodes and MultiClamp 700B Amplifier and pClamp 10 analyzer software. The membrane current changes after L0+1 and L0+10 were analyzed. RESULTS AND CONCLUSION: Prolonged stress relaxation phase was shortened with increasing preload in smooth muscle preparations. The stress relaxation phase in smooth muscle samples from urinary bladder wall was shorter than aorta samples. It was revealed that there were compliance differences between two kinds of smooth muscle samples. In aorta samples, myogenic spontaneous contraction amplitude during stress relaxation and membrane current were significantly increased with increasing preload. Increased amplitude and frequency of membrane current in aorta smooth muscle samples under high calcium concentration (3% CaCl2) were inhibited by L-type calcium channel blockade (0.05% nitrendipine). Collectively, increased preload in smooth muscle samples induced a directly decrease of compliance with an enlargement of myogenic spontaneous contraction amplitude. It appeared vital in particular in aorta samples. Membrane current significantly enhanced in spontaneous contraction period suggested the mechanical stretching ionic inward flow involved in this period. Membrane current amplitude was increased by high-preload under elevated calcium conditions; however, this change was suppressed by L-type calcium channel blockade. This study indicates quick stretching influences not only mechanically-gated channels in smooth muscle, but also the activation of L-type calcium channel. 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程