α1-肾上腺素受体介导去甲肾上腺素促大鼠培养心肌细胞肥大及肌球蛋白基因表达

目的:探讨去甲肾上腺素(NE)促心肌细胞肥大及肌球蛋白重链(MHC)基因表达作用的受体机制.方法:采用测定心肌细胞直径、数目及3H-亮氨酸(3H-Leu)掺入率的方法,观察NE及哌唑嗪(PRAZ)对大鼠培养心肌细胞肥大的影响,以斑点杂交分析NE、PRAZ在心肌细胞MHC基因表达中的作用.结果:NE明显促进心肌细胞直径增大(P＜0.01)及3H-Leu掺入率的增加(P＜0.01),并明显诱导心肌细胞β-MHC基因表达,α-MHC基因表达相应减少,PRAZ完全阻断NE的上述作用.结论:NE可促进心肌细胞肥大及MHC基因表达,该作用可能通过α1肾上腺素受体介导.     

去甲肾上腺素诱导心肌细胞肥大的机制

目的 :探讨去甲肾上腺素 (NE)诱导产生心肌细胞肥大的机制。方法 :采用测定心肌细胞直径及3 H 亮氨酸 (3 H leu)掺入率的方法 ,观察NE、哌唑嗪 (PRAZ)及普萘洛尔 (Pro)对SpragueWawley大鼠培养心肌细胞肥大的影响。结果 :NE可以促进心肌细胞直径增大及3 H leu掺入率的增加 (均P <0 .0 1)。PRAZ及Pro均可阻断NE的上述作用 ,以Pro的阻断作用最为显著。结论 :NE可促进心肌细胞肥大 ,而这种作用是通过PRAZ和Pro介导的 ,Pro起主要作用     

1-磷酸鞘氨醇受体途径诱导的心肌肥大及蛋白激酶C的调节作用

目的研究1-磷酸鞘氨醇受体途径在1-磷酸鞘氨醇(S1P)诱导乳鼠心肌细胞肥大反应中的作用。方法原代培养乳鼠心肌细胞,测定心肌细胞体积和[3H]-亮氨酸掺入量作为心肌细胞肥大的指标。实验分对照组(不加任何干预因素)、S1P组(S1P直接作用于心肌细胞)、VPC23019组(S1P1和S1P3受体抑制剂进行干预30 min后,加入S1P刺激心肌细胞)、JTE组(S1P2受体抑制剂进行干预30 min后,加入S1P刺激心肌细胞)及Staurospo-rine组(蛋白激酶C抑制剂进行干预30 min后,加入S1P刺激心肌细胞),[3H]-亮氨酸掺入法测定心肌细胞蛋白合成速率;用qPCR和Western blot法检测心肌细胞β-肌球蛋白重链的mRNA和蛋白表达水平。结果 10、100和1000 nmol/L的S1P均能增加乳鼠心肌细胞的细胞体积和[3H]-亮氨酸掺入量,尤以1000 nmol/L S1P最为明显,因而选择1000 nmol/L S1P作用心肌细胞48 h为成功的心肌细胞肥大模型。1000 nmol/L S1P处理心肌细胞48 h,可使[3H]-亮氨酸掺入量明显增加,该作用可被S1P2受体抑制剂或蛋白激...     

腺苷A1受体激动剂对异丙肾上腺素诱导心肌细胞肥大的抑制作用

目的 利用体外培养的乳鼠心肌细胞，观测腺苷A1受体激动剂，R(-)-N6-(2-phenylisopropyl)adenosine(RPIA)对异丙肾上腺素(Isoproterenol，ISO)诱导的心肌细胞肥大的抑制作用，并且探讨其作用机制。方法 在二十四孔培养板上进行新生大鼠心肌细胞培养，待细胞长成单层后，换成低血清培养基，分组给药，48h后用Lowry's法测心肌细胞的蛋白质含量；用计算机CIAS大恒细胞图象分析系统测量心肌细胞体积；用[^3H]-leucine标记法测定心肌细胞蛋白合成。结果 在低血清(0．4％)环境下，ISO明显诱导了心肌细胞蛋白含量增加，体积增大和蛋白合成增加。RPIA可以明显抑制ISO诱导的心肌细胞蛋白含量增加、体积增大、蛋白合成增加的作用，该种作用可以被A1受体拮抗剂8-cyclopentyl-1，3-dipropylxanthine(CPDPX)所拮抗。结论 在低血清环境下，ISO明显诱导心肌细胞肥大，ISO诱导心肌细胞肥大通过激动β-肾上腺受体途径。腺苷明显抑制ISO诱导的心肌肥大，其可能是通过激动A1受体途径来发挥这种抑制作用的。     

肾上腺素能受体与心肌细胞凋亡

心肌细胞凋亡参与了慢性心衰的病理生理机制。而交感神经过度激活肾上腺素能受体是慢性心衰的一个明显特征，因此，研究肾上腺素能受体在心肌细胞凋亡中的调节作用对理解β-受体阻滞剂的治疗慢性心衰中的药理作用具有重要的意义。     

α-烯醇化酶在内皮素-1诱导的肥大心肌细胞中的表达和调控通路

目的 观察内皮素-1(ET-1)诱导的心肌细胞肥大模型中细胞外信号调节激酶(ERK1/2)、磷酸化细胞外信号调节激酶(p-ERK1/2)、低氧诱导因子(HIF-1α),α-烯醇化酶(α-enolase)蛋白表达情况,探讨肥大心肌细胞α-enolase高表达的调控机制. 方法 建立ET-1诱导的心肌细胞肥大模型,从细胞表面积、细胞蛋白合成速率和肌原纤维的重排3方面进行验证;将原代培养心肌细胞随机分为4组:(1)对照组;(2)PD98059干预组;(3)ET-1刺激组;(4)PD98059+ET-1刺激组.免疫印迹方法 检测ERK1/2、p-ERK1/2、HIF-1α、α-enolase的蛋白表达. 结果 ET-1刺激后心肌细胞表面积为(1350.7±107.5)μm2,较对照组(896.1±70.2)μm2增加(P<0.05);ET-1刺激后心肌细胞[3H]亮氨酸掺入量较对照组增加[分别为(1387.9±14.8)dpm和(787.7±10.2)dpm,P<0.013;肌原纤维染色可见ET-1刺激屙心肌细胞肌原纤维排列较对照组紧密、染色浓,表明ET-1能诱导心肌细胞肥大.ERK1/2抑制剂PD98059预处理的心肌细胞在ET-1刺激后细胞表面积和细胞的[3H]亮氨酸掺入量均较ET-1刺激组减少[细胞表面积分别为(907.0±92.5)μm2和(1350.7±107.5)μm2,P<0.05;[3H]亮氨酸掺入量:(841.5±10.5)dpm和(1387.9±14.8)dpm,P<0.05].ET-1刺激后心肌细胞有p-ERK1/2表达,其抑制剂PD98059在抑制ERK1/2活化的同时也部分抑制了HIF-1α、α-enolase蛋白的表达. 结论 ERK1/2的活化与ET-1诱导的细胞肥大关系密切,在ET-1促心肌细胞肥大过程中,从MAPK/ERK1/2至HlF-1α及α-enolase这条信号通路町能参与α-enolase高表达的调控.     

腺苷A_1受体激动抑制心肌细胞肥大

目的利用体外培养的乳鼠心肌细胞,观测腺苷 A_1受体激动剂,R(-)-N6-(2-phenylisopropyl)adenosine(R-PIA)对异丙肾上腺素(Iso)诱导的心肌细胞肥大的抑制作用,并且探讨其作用机制特别是与 CaMK Ⅱ表达的关系及对心肌细胞[Ca~(2+)]i 瞬间变化的影响。方法新生大鼠心肌细胞分组给药,以10μmol/L 的异丙肾上腺素(β肾上腺素激动剂,β-AR)诱导心肌肥大,观察1 μmol/L 的 R-PIA 的作用以及钙调素激酶Ⅱ特异性抑制剂 KN93(0.2 μmol/L)防止腺苷 A_1受体的激活对心肌肥厚的作用。[~3H]亮氨酸 leucine标记法测定心肌细胞蛋白合成;Western blot 法测细胞核内 CaMK ⅡδB的表达水平;Till 图像测定系统,以 Fura-2做荧光标志,观察心肌细胞[Ca~(2+)]i 瞬间变化。结果 1 μmol/L 的 R-PIA 可以明显抑制 Iso 诱导的蛋白合成增加[(974.8±58.6)vs(1220.8±240.5)计数/(min·孔),P<0.01],抑制[Ca~(2+)]i 瞬变增加[(189.9±10.7)vs(...     

丝裂素活化蛋白激酶参与钙激动剂介导的心肌肥大

目的 :探讨不同来源的细胞内钙 （[Ca2 +] i）对心肌细胞丝裂素活化蛋白激酶 （MAPK）介导的心肌细胞肥大反应的作用。方法 :以培养的大鼠心肌细胞为模型 ,用血管紧张素 （Ang ）刺激心肌细胞外 Ca2 +跨膜内流、三磷酸肌醇 （IP3 ）刺激胞内 Ca2 +释放 ,γ-3 2 P-ATP掺入法和免疫印迹 （western blot）测 MAPK活性及蛋白含量 ,氚 -亮氨酸（3 H-L eu）、氚 -胸腺嘧啶 （3 H-Td R）掺入量作为心肌细胞肥大的指标。结果 :Ang ,IP3 刺激 15 min均能显著增加心肌细胞 MAPK活性及蛋白含量 ,并提高 3 H-L eu,3 H-Td R掺入量 ,与对照组心肌细胞相比差异显著 （P<0 .0 1）。结论 :钙激动剂诱导的 MAPK活性及含量的增加参与了心肌细胞肥大 ,心肌细胞的肥大与 [Ca2 +] i 的来源无关     

β3-肾上腺素能受体在心血管系统中的研究进展

人的心脏存在α和β两大肾上腺素能受体家族 ,β肾上腺素能受体 (简称 :β受体 )是调节心脏功能最有力的刺激物[1] 。较早时候发现与心脏功能特别相关的是β1和β2 受体 ,而 β3受体主要分布于白色和棕色脂肪组织 ,跟心脏关系不大 ,其作用限于代谢和糖尿病。新近发现在心脏 β3受体兴奋表现为负性变力作用 ,特别是心衰时 ,β3受体含量明显增加 ,这种作用增加更显著 ,使心脏功能进一步恶化。本文着重阐明β3受体在心血管系统中的作用。1　β肾上腺素能受体的分类根据药理学方法和分子克隆 ,心脏存在 β1、β2 、β3三种肾上腺素能受体[2 ] ,…     

腺苷A1受体激动剂对异丙肾上腺素诱导心肌细胞肥大的抑制作用

目的利用体外培养的乳鼠心肌细胞,观测腺苷A1受体激动剂,R(-)-N6-(2-phenylisopropyl)adenosine (R-PIA ) 对异丙肾上腺素(Isoproterenol,ISO)诱导的心肌细胞肥大的抑制作用,并且探讨其作用机制.方法在二十四孔培养板上进行新生大鼠心肌细胞培养,待细胞长成单层后,换成低血清培养基,分组给药,48 h后用Lowry's法测心肌细胞的蛋白质含量;用计算机CIAS大恒细胞图象分析系统测量心肌细胞体积;用[3H]-leucine标记法测定心肌细胞蛋白合成.结果在低血清(0.4%)环境下,ISO明显诱导了心肌细胞蛋白含量增加,体积增大和蛋白合成增加.R-PIA 可以明显抑制ISO诱导的心肌细胞蛋白含量增加、体积增大、蛋白合成增加的作用,该种作用可以被A1受体拮抗剂8-cyclopentyl-1,3-dipropylxanthine(CPDPX)所拮抗.结论在低血清环境下,ISO明显诱导心肌细胞肥大,ISO诱导心肌细胞肥大通过激动β-肾上腺受体途径.腺苷明显抑制ISO诱导的心肌肥大,其可能是通过激动A1受体途径来发挥这种抑制作用的.     

调节PCBP2表达水平对心肌细胞肥大的影响

目的：研究调节PCBP2表达水平对心肌细胞肥大的影响 方法：分离、培养原代乳鼠心肌细胞;在体外应用儿茶酚胺类物质（血管紧张素II、异丙肾上腺素、苯肾上腺素）来诱导心肌细胞。诱导心肌细胞发生肥大,通过对心肌细胞表面积和心肌肥大标志物的检测,观察敲低和过表达PCBP2对血管紧张素II诱导的心肌细胞肥大的影响。 结果：血管紧张素II、异丙肾上腺素、苯肾上腺素均可诱导心肌细胞肥大,使心肌细胞表面积增加。敲低心肌细胞PCBP2后,血管紧张素II诱导心肌细胞肥大的程度更大,使心肌细胞表面积显著增大;而过表达心肌细胞PCBP2后,可有效抑制血管紧张素II诱导的心肌细胞肥大,使心肌细胞表面积显著缩小。 结论：PCBP2参与调节心肌细胞肥大,是抑制病理条件下心肌细胞肥大的负性调节因子。     

Stimulation of hypertrophy of cultured neonatal rat heart cells through an alpha 1-adrenergic receptor and induction of beating through an alpha 1- and beta 1-adrenergic receptor interaction. Evidence for independent regulation of growth and beating

Catecholamines may be one of the molecular signals linking increased circulatory demand to myocardial hypertrophy, and I have found previously that norepinephrine stimulates hypertrophy of cultured neonatal rat heart muscle cells through an alpha 1-adrenergic receptor. Since catecholamine stimulation of contractility is believed to be under beta-adrenergic control, I asked whether these cultured heart cells had dual pathways regulating growth and contractility through alpha- and beta-adrenergic receptors, respectively. I examined the effect of adrenergic agents on hypertrophy and beating of myocytes in serum-free cultures. Hypertrophy was defined as an increase in myocyte surface area and in cell protein content, measured by a radioisotopic method, and chronotropic activity was examined visually. Norepinephrine and epinephrine were equipotent stimulants of hypertrophy and beating, increasing cell protein and area 1.5- to 2-fold, and the proportion of beating cells from 5% or less to 95%. Response maxima occurred 24-48 hours after exposure, and EC50 were 20-200 nM. Studies with other agonists (phenylephrine, methoxamine, clonidine, isoproterenol, dopamine) and antagonists (prazosin, terazosin, yohimbine, propranolol, betaxolol, ICI 118,551) indicated that hypertrophy was mediated through an alpha 1-adrenergic receptor, whereas the induction of beating required both alpha 1- and beta 1-receptor activation. Hypertrophied cells with minimal beating were produced by alpha-stimulation, alone. In contrast, alpha-plus beta-stimulation in the presence of cycloheximide to inhibit protein synthesis resulted in maximum beating but no hypertrophy. These findings imply that growth and beating can be regulated independently through separate cellular pathways.     

CREG, a new regulator of ERK1/2 in cardiac hypertrophy

OBJECTIVES: The cellular repressor of E1A-stimulated genes (CREG), a mannose-6-phosphate-containing secreted glycoprotein, enhances differentiation and inhibits proliferation. In this study, our aim was to understand the role of CREG in cardiac hypertrophy. METHODS: Two models of cardiac hypertrophy were used: the in vivo pressure-overloaded rat cardiac hypertrophy and the in vitro stretched neonatal rat cardiomyocyte hypertrophy. CREG's function in cardiac cells was investigated after over-expression or antisense inhibition of CREG. RESULTS: We found reduced CREG expression in rat hearts after the in vivo overload, as shown by Northern blot analysis. CREG over-expression inhibited cardiac cell growth, as demonstrated by reduced protein content, cell area and ERK1/2 level in cultured neonatal rat cardiomyocytes, and by the reduced proliferation of cultured neonatal rat cardiac fibroblasts. Additionally, over-expression of CREG dampened the stretched cardiomyocyte hypertrophy through ERK1/2. On the other hand, the opposite effects were observed when CREG expression was decreased using antisense. This modulation of CREG expression resulted in no changes in the cardiomyocyte expressions of the hypertrophic or apoptotic signaling molecules such as protein kinase C (PKC) epsilon, PKC beta1, PKC alpha, PKC beta2, PKC delta, JNK1/2, p38, p53, Bax, Bcl2 and Fas. CONCLUSIONS: CREG was found to inhibit cardiac cell growth as a novel regulator of ERK1/2 and might participate in the development of cardiac hypertrophy under pressure overload. The insight that CREG inhibited the growth in rat hearts in vivo and in cardiac cells in vitro provides new clues for further investigation of the mechanism of heart remodeling.     

Peroxisome proliferator-activated receptor beta/delta activation improves angiotensin II-induced cardiac hypertrophy in vitro

Agonists of the peroxisome proliferator-activated receptor alpha (PPARalpha) and gamma (gamma) exert anti-proliferative and anti-inflammatory effects that led to the testing of these drugs in experimental cardiac hypertrophy. However, the effect of PPAR beta/delta (beta/delta) agonists in hypertrophy is not yet known. In this paper, an experiment was conducted to explore whether PPARbeta/delta activation has an effect on cardiac hypertrophy. An in vitro cardiomyocyte hypertrophy from neonatal rats was induced with Angiotensin II (Ang II1micromol x L(-1)) stimulation. For the examination of PPAR beta/delta effect, the cultured rat cardiac myocytes were pretreated with GW0742 (10 micromol.L(-1)), an agonist of PPARbeta/delta, for 48h before Ang II stimulation. The following parameters in the cultured cells were determined: surface areas of myocytes were measured by the NIH Image Software; (3)H-leucine incorporation into myocytes was counted by liquid scintillometer; mRNA expression of PPARbeta/delta, ANP, BNP, MMP9, MMP2, and IL-1beta was detected by RT-PCR; PPARbeta/delta protein expression was evaluated with immunofluorescence staining; GW0742 could ameliorate Ang II-induced cardiomyocyte hypertrophy, as indicated by its inhibitory effects on the surface area of myocytes, and ANP and BNP mRNA expressions in myocytes and (3)H-leucine incorporation into myocytes. Meanwhile, GW0742 pretreatment exerted inhibition on mRNA expression augmentation of such cytokines as MMP9, MMP2, and IL-1beta in hypertrophic myocytes. In addition, the down-regulated expression of PPARbeta/delta mRNA and protein in hypertrophic myocytes was also significantly reversed by GW0742. We demonstrate for the first time that GW0742 exerts a beneficial effect on Ang II-induced cardiac hypertrophy and the relation to inflammation response.     

Essential role of Rho/ROCK-dependent processes and actin dynamics in mediating leptin-induced hypertrophy in rat neonatal ventricular myocytes

BACKGROUND: Obesity is associated with increased leptin production, which may contribute to cardiac hypertrophy. Although leptin has been shown to produce cardiomyocyte hypertrophy, its mechanism of action is far from clear. Rho proteins have been suggested as major contributors to cardiac hypertrophy, although their potential role in mediating the effect of leptin has not been studied. METHODS: We determined the role of Rho and Rho-associated kinase (ROCK) as mediators of leptin-induced cell hypertrophy in cultured neonatal rat ventricular myocytes. RESULTS: Leptin (3.1 nmol/L) significantly increased cell surface area by 32+/-5% and leucine incorporation by 43 +/- 7%. These effects were associated with significant activation of RhoA to 450 +/- 40% of pre-leptin levels that was attenuated by pretreatment with an anti-leptin receptor (anti-OBR) antibody (166 ng/mL) to 120 +/- 20% of control values. Both the RhoA inhibitor C3 exoenzyme and ROCK inhibitor Y-27632 potently attenuated leptin-induced increased cell surface area and leucine incorporation. The hypertrophic effect of leptin was associated with an increase in phosphorylation of the actin binding protein cofilin to 290 +/- 20% of control values. In addition, the increase in polymerization of actin, as reflected by a decrease in the G/F-actin ratio, was significantly inhibited by both the anti-OBR antibody and Y-27632. Leptin-induced hypertrophy was also attenuated by disruption of actin filaments with 50 nmol/L latrunculin B. RhoA pathway inhibitors and latrunculin B also both attenuated leptin-induced ERK1/2 and p38 activation. CONCLUSION: Our results indicate that the activation of Rho and actin dynamics play a pivotal role in leptin signaling leading to the development of cardiomyocyte hypertrophy.     

肿瘤抑制因子PTEN与心肌肥大关系的研究

目的 观察肿瘤抑制因子PTEN在心肌肥厚大鼠心肌组织以及在血管紧张素Ⅱ诱导的肥大心肌细胞中的表达,探讨PTEN在心肌肥大发生发展中的作用以及相关机制。方法采用腹主动脉狭窄术制备压力超负荷心肌肥厚动物模型,及血管紧张素Ⅱ诱导新生大鼠心肌细胞肥大模型,应用逆转录-聚合酶链式反应(RT-PCR)方法、Western blot及免疫组化等方法,分别检测各组PTEN mRNA和蛋白表达的变化,以及PTEN蛋白在心肌细胞中的定位。结果(1)与对照组相比,心肌肥厚组大鼠左室肌PTEN mRNA和蛋白表达均明显减少;血管紧张素Ⅱ诱导心肌细胞肥大组PTEN蛋白表达明显减少。(2)与心肌肥厚组相比,卡托普利组大鼠左室心肌PTEN mRNA和蛋白表达增加,接近对照组。(3)免疫组化实验结果显示心肌细胞胞核内有阳性免疫产物生成,提示PTEN蛋白定位于心肌细胞核内。结论PTEN在心肌肥大发生发展中可能起负调控作用,该作用与肾素-血管紧张素系统密切相关。     

阿托伐他汀在1-磷酸鞘氨醇诱导心肌细胞肥大中的作用

目的研究阿托伐他汀对1-磷酸鞘氨醇(S1P)诱导乳鼠心肌细胞肥大反应中的作用。方法原代培养乳鼠心肌细胞,测定心肌细胞体积和[3H]-亮氨酸掺入量作为心肌细胞肥大的指标。乳鼠心肌细胞使用不同浓度的阿托伐他汀(atorvastatin),加入S1P,[3H]-亮氨酸掺入量作为心肌细胞蛋白摄取量;分别用qPCR和Western blot法检测心肌细胞的β-肌球蛋白(β-MHC)的mRNA和蛋白质表达水平;用qPCR检测心肌细胞的心房利钠肽(ANF)的mRNA表达水平。结果与S1P组比较,阿托伐他汀10μmol/L处理组[3H]-亮氨酸掺入率减少[(234.89%±31.23%)比(342.23%±31.60%),P=0.205],β-MHC的mRNA和蛋白表达水平下降[(0.59±0.14)比(0.84±0.20),P=0.318]和[(0.55±0.09)比(0.98±0.15),P=0.223],ANF的mRNA表达水平降低[(0.51±0.13)比(0.76±0.19),P=0.445];与S1P组比较,阿托伐他汀20μmol/L处理组[3H]-亮氨酸掺入率明显减少[(189.07%±17.69%)比(342.23%±31.60%),P<0.01],β-MHC的mRNA和蛋白表达水平显著下降[(0.50±0.12)比(0.84±0.20),P<0.01]和[(0.35±0.08)比(0.98±0.15),P<0.01],ANF的mRNA水平明显降低[(0.47±0.12)比(0.76±0.19),P<0.01]。结论阿托伐他汀可抑制S1P诱导的心肌细胞肥大,并可减少S1P诱导的β-MHC和ANF表达。     

腺苷A1受体与к阿片肽受体激活对异丙肾上腺素诱导的心肌细胞肥大的交互作用

目的观察腺苷A1受体与κ阿片肽受体(κ-OR)激活对异丙肾上腺素(Iso)诱导的心肌细胞肥大的交互作用及机制。方法体外培养大鼠乳鼠心肌细胞,以Iso 10μmol/L诱导心肌细胞肥大,观察腺苷A1受体激动剂R(-)-N6-(2-phenylIsopropyl)adenosine(R-PIA)1μmol/L和κ-OR激动剂U50,488H1μmol/L对其作用,进一步探讨腺苷A1受体拮抗剂8-cyclopentyl-1,3-dipropylxanthine(CPDPX)0.1μmol/L存在时κ-OR的激活对细胞肥大的影响和κ-OR拮抗剂nor-binaltorphimine(NOR-BNI)1μmol/L存在时腺苷A1受体的激活对心肌细胞肥大的影响。通过Lowry法测心肌细胞蛋白含量;消化分离法及计算机图像分析系统测细胞体积;以Fluo-3/AM为荧光探针,共聚焦显微镜下测量心肌细胞内[Ca2+]i变化;RT-PCR法检测心肌细胞心房钠尿肽(ANP)的mRNA表达。结果 10μmol/LIso可以诱导心肌细胞肥大,1μmol/L的R-PIA(腺苷A1受体激动剂)可以明显抑制Iso诱导的心肌细胞蛋白合成增加、体积增大、ANPmRNA表达增加、心肌细胞内[Ca2+]i荧光强度增大,该抑制作用可以被1μmol/Lκ-OR拮抗剂NOR-BNI部分阻断;κ-OR激动剂U50,488H1μmol/L可以明显抑制Iso诱导的心肌细胞蛋白合成增加、体积增大、ANPmRNA表达增加、心肌细胞内[Ca2+]i荧光强度增大,该抑制作用可以被腺苷A1受体拮抗剂CPDPX部分阻断。结论腺苷可通过激动A1受体、阿片肽可通过激动κ受体抑制Iso诱导的心肌肥大,二者可以通过影响心肌细胞内[Ca2+]i浓度的增大而交互抑制Iso诱导的心肌肥大。     

促红细胞生成素对乳鼠心肌细胞肥大及P13K/Akt-eNOS信号转导通路的影响

目的 探讨促红细胞生成素(EPO)对血管紧张素Ⅱ(AngⅡ)诱导的肥大心肌细胞的影响,以及磷脂酰肌醇3激酶(PI3K)/丝氨酸苏氨酸激酶(Akt)-内皮型一氧化氮合酶(eNOS)信号转导通路在其中的作用.方法 分离乳鼠心肌细胞,利用AngⅡ诱导建立心肌细胞肥大模型,以心肌细胞表面积和心钠素(ANF)mRNA表达作为心肌细胞肥大观察指标.观察不同浓度EPO对肥大心肌细胞的影响,并利用PI3K抑制剂LY294002和一氧化氮合酶抑制剂L-NAME对其相关机制进行探讨,I司时对细胞培养液中一氧化氮(NO)浓度进行检测,蛋白免疫印迹法检测磷酸化Akt(p-Akt)、Akt、磷酸化eNOS(p-eNOS)和eNOS蛋白表达情况.结果 20 U/ml EPO能抑制由AngⅡ诱导的心肌细胞肥大,表现为心肌细胞表面积和ANF mRNA表达均减少(P＜0.05).EPO能激活Akt,促进eNOS及p-eNOS表达增加(均P＜0.05),并使NO合成增加(P＜0.01).LY294002和L-NAME能逆转EPO的抗心肌细胞肥大作用,减少NO产最(P＜0.05).蛋白免疫印迹法榆测显示,LY294002能够抑制EPO对p-Akt、p-eNOS和eNOS蛋白表达的促进作用,而L-NAME能抑制eNOS的磷酸化(均P＜0.05).结论 EPO能够抑制AngⅡ诱导的心肌细胞肥大,该作用可能是通过激活P13K/Akt信号转导通路,促进eNOS表达与活化,从而促进NO的合成来实现的.     

Arginine vasopressin-induced hypertrophy of cultured rat aortic smooth muscle cells

Recently we reported that the contractile agonist angiotensin II induces hypertrophy, not hyperplasia, in cultured rat aortic smooth muscle cells (Geisterfer AAT, Peach MJ, Owens GK: Angiotensin II induces hypertrophy, not hyperplasia, of cultured rat aortic smooth muscle cells. Circ Res 1988;62:749-756). We have further explored the hypothesis that contractile agonists are important regulators of smooth muscle cell growth by examining the effects of another contractile agonist, arginine vasopressin, on growth of cultured rat aortic smooth muscle cells. Autoradiographic analysis as well as cell number determinations showed that arginine vasopressin (1 microM) did not stimulate proliferation in cells made quiescent in a defined serum-free media nor did it augment proliferation in 0.4% fetal bovine serum. However, flow cytometric analysis of cellular protein content demonstrated that arginine vasopressin (1 microM) did induce cellular hypertrophy in quiescent cultures after 4 days of treatment, increasing smooth muscle cell protein content by 35% as compared with vehicle-treated controls. The increase in protein content showed a concentration dependence. Cellular hypertrophy was accompanied by an increase in [35S]methionine incorporation, which was elevated 45% by 24 hours. Both the increase in [35S]methionine incorporation and the increase in protein content could be prevented by the specific arginine vasopressin receptor antagonist. [1-beta-mercapto-beta,beta-cyclopentamethylene propionic acid), 2-(O-methyl)tyrosine] arginine vasopressin. An increase in [35S]methionine incorporation was observed between 12 and 24 hours after treatment of quiescent smooth muscle cells for only 5 minutes with arginine vasopressin (1 microM). Arginine vasopressin-induced increases in [35S]methionine incorporation was increased within 6 hours after treatment. These studies show that arginine vasopressin, like angiotensin II, induces hypertrophy but not hyperplasia of cultured rat aortic smooth muscle cells.