左旋精氨酸对离体培养SHR大鼠主动脉内皮细胞一氧化氮合成酶活性的影响

目的：探讨左旋精氨酸对离体培养SHR大鼠主动脉内皮细胞一氧化氮合成酶（nitric oxidative synthase,NOS)活性的影响。方法：6周龄雄性SHR大鼠，取其主动脉，采用贴块法进行体外内皮细胞培养，传达6－8代，将细胞分成实验组和对照组，实验组在生长液中加入1mol/L左旋精氨酸，对照组不施干预措施，分别在加入左旋精氨酸后1／2，1、2、4小时取二组细胞，反复冻融三次使细胞破裂，用分光光度法测定细胞内NOS活性。结果：内皮细胞对左旋精氨酸较敏感，实验组加入左旋精氨酸1／2小时后，NOS活性即上升，1小时达最高，随后下降，至4小时恢复正常。结论：左旋精氨酸可增强离体SHR大鼠主动脉内皮细胞NOS活性。     

沙格列汀对过氧化氢诱导损伤的血管内皮细胞二甲基精氨酸二甲胺水解酶/非对称性二甲基精氨酸/内源性一氧化氮合酶通路影响的研究

目的观察二肽基肽酶-4(DPP-4)抑制剂沙格列汀对过氧化氢(H2O2)诱导损伤的血管内皮细胞二甲基精氨酸二甲胺水解酶/非对称性二甲基精氨酸/内源性一氧化氮合酶(DDAH/ADMA/eNOS)通路的影响。方法以培养人脐静脉内皮细胞株(HUVEC)作为靶细胞,在内皮细胞培养基中加入100μmol/L的H2O2制备细胞损伤模型,以20μmol/L沙格列汀进行干预,观察24~72h,检测细胞上清一氧化氮(NO)含量、ADMA浓度,检测细胞中NOS活性、DDAH活性及DDAH蛋白表达量。结果H2O2作用HUVEC后,细胞上清中NO含量降低,而ADMA浓度增加(P0.05)。细胞中NOS活性、DDAH活性、DDAH-Ⅱ蛋白表达量降低(P0.05);而加入沙格列汀,细胞上清中NO含量升高,ADMA浓度降低(P0.05)。细胞中NOS活性、DDAH活性、DDAH-Ⅱ蛋白表达量升高(P0.05)。结论沙格列汀通过对DDAH/ADMA/eNOS通路的调节作用改善H2O2诱导的内皮细胞NO生成减少。     

普罗布考对大鼠心脏微血管内皮细胞RAGE表达的影响

目的 观察普罗布考对大鼠心脏微血管内皮细胞糖基化终末产物（AGEs）受体（RAGE）表达的影响.方法 体外原代培养心脏微血管内皮细胞.空白组加无血清培养液培养,AGEs组加AGEs（100 mg/L）孵育,普罗布考（5、10 μmol/L）组用普罗布考（5、10 μmol/L）分别作用细胞30 min后,加入AGEs（100 mg/L）再孵育24 h.各组分别作用于心脏微血管内皮细胞24h,免疫组化法和Western blot法检测RAGE蛋白表达.结果 AGEs组与空白组RAGE蛋白表达比较,P＜0.05;普罗布考10μmol/L组与AGEs组比较,P＜0.05.结论 普罗布考能够抑制AGEs诱发的心脏微血管内皮细胞RAGE的表达,从而抑制氧化应激的发生.     

四氢生物喋呤对内皮细胞产生一氧化氮和超氧阴离子的影响

目的探讨四氢生物喋呤(BH4)对人脐静脉内皮细胞产生一氧化氮(NO)和超氧阴离子(O-2)的影响.方法在培养液中分别加入不同浓度的D-葡萄糖、胰岛素和BH4,24 h后取细胞培养液分别测定一氧化氮合酶(NOS)、超氧化物歧化酶(SOD)活性、NO和O-2浓度.结果BH4(10、100、500μmol/L)使内皮细胞NOS活性增高,500 μmol/L BH4使内皮细胞NO产生增加,10或100 μmol/LBH4对内皮细胞产生NO有增加的趋势,但与对照组比较无显著性差异(P＞0.05);25 mmol/L葡萄糖+BH4(10、100、500 μmol/L)对内皮细胞产生NO与对照组比较无显著性差异(P＞0.05);高浓度胰岛素(10、100、1 000 mU/L)+BH 4(10、100、500 μmol/L)使内皮细胞NOS活性增强,NO产生增加.BH4(10、100、500μmol/L)对内皮细胞SOD活性无明显影响,但可以改善25 mmol/L葡萄糖对内皮细胞SOD活性的影响;胰岛素+BH4对内皮细胞SOD活性无明显影响(P＞0.05).BH4(10、100、500 μmol/L)使内皮细胞产生O-2减少,并可以改善25 mmol/L葡萄糖对内皮细胞产生O-2影响;胰岛素+BH4组O-2浓度明显低于对照组和不同浓度胰岛素组(P＜0.01).结论BH4可以增加培养的人脐静脉内皮细胞NOS活性,使NO产生增加而使O-2水平下降.     

L-精氨酸对高糖引起内皮功能失调的保护作用

目的通过研究L-精氨酸和N^G-硝基-L-精氨酸-甲基酯对人脐静脉内皮细胞产生一氧化氮和超氧阴离子的影响以探讨L-精氨酸对高糖引起内皮功能失调的保护作用。方法不同浓度L-精氨酸、N^G-硝基-L精氨酸-甲基酯、葡萄糖和胰岛素加入体外培养的人脐静脉内皮细胞，24h后分别测定细胞培养液中一氧化氮舍酶和超氧化物歧化酶活性及一氧化氮和超氧阴离子浓度。结果25mmol／L葡萄糖使内皮细胞一氧化氮合酶活性增高，一氧化氮产生增加，超氧化物歧化酶活性下降，超氧阴离子产生增加；L-精氨酸对一氧化氮舍酶、一氧化氮、超氧化物歧化酶的影响与对照组相比无显著性差异（P〉0．05）。但可以使超氧阴离子产生减少；25mmol／L葡萄糖＋L-广精氨酸使内皮细胞一氧化氮舍酶活性增强，一氧化氮产生增加，L-精氨酸可以改善高糖引起的超氧阴离子升高。不同浓度的胰岛素使内皮细胞一氧化氮合酶活性增高，一氧化氮产生增加，对超氧化物歧化酶活性和超氧阴离子产生无明显影响；不同浓度胰岛素＋L-精氨酸使内皮细胞一氧化氮合酶活性增强，一氧化氮产生增加，对超氧化物歧化酶活性无明显影响，但可以使超氧阴离子水平降低。100μmol／LN^G-硝基-L-广精氨酸-甲基酯使内皮细胞一氧化氮合酶活性下降，一氧化氮产生减少，对超氧化物歧化酶活性无明显影响，但使超氧阴离子产生增加；25mmol／L葡萄糖＋N^G-硝基-L-精氨酸-甲基酯使内皮细胞一氧化氮合酶活性下降，一氧化氮产生减少，但对高糖引起的超氧化物歧化酶活性下降和超氧阴离子升高无明显影响。10mu胰岛素＋10μmol／L N^G-硝基-L-精氨酸．甲基酯和100mu胰岛素＋100μmol／L N^G-硝基-L-精氨酸-甲基酯使内皮细胞一氧化氮合酶活性下降，一氧化氮产生减少，对超氧化物歧化酶活性无明显影响，但使超氧阴离子升高。结论L-精氨酸对一氧化氮合酶、一氧化氮、超氧化物歧化酶无明显影响，但可以使超氧阴离子产生减少；N^G-硝基-L-精氨酸-甲基酯使内皮细胞一氧化氮合酶活性下降。一氧化氮产生减少，对超氧化物歧化酶活性无明显影响，但使超氧阴离子产生增加。     

氟伐他汀对人脐静脉内皮细胞游离钙离子水平及内皮型一氧化氮合酶活性的影响

目的:观察氟伐他汀对人脐静脉内皮细胞(HUVECs)游离钙离子水平及内皮型一氧化氮合酶(eNOS)活性的影响及可能机制。方法:体外培养HUVECs,随机分为5组:空白对照组,氟伐他汀(10-8,10-7,10-6,10-5mol/L)组。采用硝酸还原酶法测定细胞上清液中NO含量,液体闪烁计数仪测定L-[3H]-精氨酸和L-[3H]-瓜氨酸的含量,用激光共聚焦扫描显像系统检测内皮细胞内游离钙离子浓度([Ca2 ]i)水平的变化。结果:与空白对照组比较,10-8,10-7,10-6,10-5mol/L氟伐他汀孵育细胞12h后可显著升高HUVECs细胞内eNOS活性,促进NO释放,同时伴有[Ca2 ]i升高,且呈浓度依赖性。另外,10-5mol/L氟伐他汀在0～12h时间段呈时间依赖性增高eNOS活性,作用12h使eNOS活性达到最高(P<0.01)。结论:氟伐他汀呈浓度依赖性升高HUVECseNOS活性和促进NO释放,该作用与其增加内皮细胞内[Ca2 ]i有关。     

非对称性二甲基精氨酸对人脐静脉内皮细胞功能的影响

目的 探讨非对称性二甲基精氨酸对人脐静脉内皮细胞表达可溶性细胞间粘附分子1、内皮素1、一氧化氮的影响。并观察不同浓度L-精氨酸对非对称性二甲基精氨酸效应的拮抗作用。方法 以不同浓度的非对称性二甲基精氨酸（分别为1、4、8、12和16μmol/L）与人脐静脉内皮细胞共育及固定浓度的非对称性二甲基精氨酸（16μmol／L）加不同浓度的L-精氨酸（分别为0.2、0．4、0．8、1．6和3．2mmol／L）与人脐静脉内皮细胞共育24h，分别用酶联免疫吸附法、硝酸还原酶法、放射免疫法检测培养基中可溶性细胞间粘附分子1、内皮素1及一氧化氮的浓度。结果 非对称性二甲基精氨酸呈剂量依赖性增加人脐静脉内皮细胞可溶性细胞间粘附分子1和内皮素1的表达，降低一氧化氮的表达（P〈0．05），接近生理范围的非对称性二甲基精氨酸（即1μmol／L）对内皮功能没有明显的影响；外源性补充L-精氨酸可逆转非对称性二甲基精氨酸的效应，且呈剂量依赖性（P〈0．05），但当外源性L-精氨酸的剂量大到一定程度时即加入L-精氨酸／非对称性二甲基精氨酸〉100时，内皮功能并不能得到进一步改善。相关分析显示培养基中可溶性细胞间粘附分子1、一氧化氮、内皮素1的表达和加入非对称性二甲基精氨酸的的浓度明显相关。其相关系数r分别为0．943、-0．937和0．934（P〈0.01）。结论 非对称性二甲基精氨酸可通过增加内皮细胞表达可溶性细胞间粘附分子1和内皮素1，减低内皮细胞产生一氧化氮来导致内皮功能紊乱，且内皮功能紊乱的程度与非对称性二甲基精氨酸的浓度明显相关；外源性补充L-精氨酸可逆转非对称性二甲基精氨酸的效应；寻找有效的方法调节非对称性二甲基精氨酸的浓度可能是改善内皮功能，防治心血管疾病的一个新目标。     

硫化氢对乳鼠心肌细胞缺氧-复氧损伤的保护作用

目的:研究不同浓度的硫化氢(H_2S)对缺氧不同时间的乳鼠心肌细胞损伤的直接影响及其对复氧损伤的间接影响,分析其对乳鼠心肌细胞缺氧-复氧损伤的保护作用.方法:原代培养的乳鼠心肌细胞随机分为正常对照组、缺氧硫氢化钠(NaHS)0组、缺氧硫氢化钠 100 μmol/L组、缺氧硫氢化钠 200 μmol/L组、缺氧硫氢化钠400 μmol/L组以及缺氧-复氧硫氢化钠0组、缺氧-复氧硫氢化钠100 μmol/L组、缺氧-复氧硫氢化钠 200 μmol/L组、缺氧-复氧硫氢化钠 400 μmol/L组.在缺氧24 h、48 h、72 h后及复氧2 h后均检测细胞存活数量、培养液中乳酸脱氢酶(LDH)活性.结果:缺氧硫氢化钠100 μmol/L组、缺氧硫氢化钠200 μmol/L组和缺氧硫氢化钠 400 μmol/L组缺氧培养24 h、48 h和72 h后与各自时间点缺氧硫氢化钠0组比心肌细胞存活数量升高(P<0.01)、培养液中乳酸脱氢酶活性降低(P<0.01),差异均有统计学意义;缺氧硫氢化钠 200 μmol/L组和缺氧硫氢化钠 400 μmol/L组在缺氧培养24 h后较缺氧硫氢化钠100 μmol/L组心肌细胞存活数量升高(P<0.01)、培养液中乳酸脱氢酶活性降低(P<0.05～0.01),差异均有统计学意义.缺氧-复氧硫氢化钠100 μmol/L组、缺氧-复氧硫氢化钠200 μmol/L组和缺氧缺氧-复氧硫氢化钠400 μmol/L组缺氧培养24 h、48 h、72 h并复氧2 h后较各自时间点缺氧-复氧硫氢化钠0组比心肌细胞存活数量升高(P<0.01)、复氧后心肌细胞乳酸脱氢酶漏出量降低(P<0.01),差异均有统计学意义.结论:100~400 μmol/L 硫氢化钠对缺氧-复氧心肌细胞具有保护效果.200~400 μmol/L 硫氢化钠对缺氧24 h的心肌细胞保护作用较好.     

胰岛素对牛主动脉内皮细胞一氧化氮合酶(NOS)活性及诱生型NOS mRNA表达的影响

目的　观察胰岛素对牛主动脉内皮细胞一氧化氮合酶 (NOS)活性及诱生型NOS(iNOS)基因表达的影响。方法　原代培养牛降主动脉内皮细胞 ,在不同浓度胰岛素条件下孵育 2 4h ,用比色法检测NOS活性 ,用半定量RT PCR检测内皮细胞iNOSmRNA表达。结果　药理浓度胰岛素 (10 -7mol/L)比生理浓度胰岛素 (10 -10 mol/L)条件下NOS活性及iNOSmRNA表达均显著增高 (均P <0 .0 5 )。结论　高胰岛素浓度状态下大血管病变可能与内皮细胞iNOS过度表达及合成一氧化氮功能异常有关。     

心肌成纤维细胞NOS-NO系统活性的变化及其与AVP的关系

目的 :探讨无干预和血管升压素 （AVP）干预条件下 ,心肌成纤维细胞 （CFs）的一氧化氮合酶—氧化氮 （NOS-NO）系统活性的变化。方法 :胰酶消化法分离、培养新生 SD大鼠 CFs,采用硝酸还原酶法和分光光度法观察无干预和 AVP干预条件下 ,不同培养时间对 CFs的 NOS- NO系统活性的影响。结果 :1无干预条件下 ,CFs的 NO含量和 NOS活性随培养时间延长而增高 ,其中 36 h（4 2± 5 μmol· L- 1 ,37± 5 U· m L- 1 ）显著高于 6 h（14± 3μmol·L- 1 ,10± 4U· m L- 1 ）以及 12 h（2 1± 3μm ol· L- 1 ,15± 3U· m L- 1 ） （均 P<0 .0 5 ）。 2 AVP干预条件下 ,CFs的NO含量和 NOS活性也随培养时间延长而增高 ,其中 2 4h（6 5± 6 μmol· L- 1 ,70± 4U· m L- 1 ） ,36 h（6 2± 1μm ol· L- 1 ,6 9± 6 U· m L- 1 ）都显著高于 6 h （34± 4μmol· L- 1 ,36 +2 U· m L- 1 ）以及 12 h的 （4 5± 4μmol· L- 1 ,45± 1U· m L- 1 ） （均 P<0 .0 5 ）。 3AVP干预条件下 CFs的 NO含量和 NOS活性均较无干预条件下显著增高 ,且 NO含量随 NOS活性增高而增高 ,二者呈显著正相关 （无干预条件下 r=0 .837,P<0 .0 1;AVP干预条件下 r=0 .936 ,P<0 .0 1）。结论 :AVP提高 CFs的 NOS- NO系统活性 ,CFs的 NOS- NO系统活性与培养和 AVP?     

Phenotypic properties and characteristics of superoxide production by mouse coronary microvascular endothelial cells.

Coronary microvascular endothelial cells exert (patho)physiological effects on the function of cardiac myocytes, which may be studied experimentally using pure cell populations. As an essential pre-requisite to the investigation of cells from gene-modified mice, we studied the phenotypic properties of coronary microvascular endothelial cells isolated from normal mice, and biochemically characterized the superoxide production by these cells. Microvascular endothelial cells were isolated from devitalized mouse ventricular tissue after sequential digestion with collagenase, trypsin and DNase. Coronary microvascular endothelial cells were separated from cardiac myocytes and other cells by differential centrifugation, plating and culture. Mouse coronary microvascular endothelial cells showed an irregular "cobblestone" morphology at confluence, were >98% positive for CD31 by FACS analysis, and were also positive for VE-cadherin and endothelial-type nitric oxide synthase (eNOS) by confocal microscopy. The cells took up fluorescently labelled, acetylated low-density lipoprotein, but were negative for a alpha -smooth muscle actin, desmin and cytokeratin. Unlike human endothelial cells, mouse coronary microvascular endothelial cells only weakly expressed von Willebrand factor. Immunoblotting showed that the mouse cells expressed components of a phagocyte-type NADPH oxidase. They exhibited NADPH-dependent O(2)(-)-generating activity, which was increased by angiotensin II but completely inhibited by diphenyleneiodonium. Thus, mouse coronary microvascular endothelial cells express both eNOS and NADPH oxidase, interactions between which may play a role in endothelial cell pathophysiology.     

动脉粥样硬化家兔主动脉壁与红细胞L-精氨酸/一氧化氮系统变化

目的 观察动脉粥样硬化时主动脉与循环中红细胞L－精氨酸（L－Arg）／一氧化氮（ＮＯ）系统变化的关系。方法 建立动脉粥样硬化模型，喂养家兔１２只，分为动脉粥样硬化组（ＡＳ组）和对照组，分别喂以高脂饮食和普通饮食，６周后取静脉血，并处死动物，测定主动脉和循环中红细胞Ｌ－Ａrg转运，一氧化氮合酶（ＮＯＳ）活性及一氧化氮生成量。结果 动脉粥样硬化主动脉平滑肌细胞Ｌ－Ａrg/NOS/NO系统活性增强，而其内皮细胞ＮＯＳ活性降低；循环中红细胞Ｌ－Ａrg的跨膜转运速率和亲和力降低，其ＮＯＳ活性下降。结论 循环中红细胞Ｌ－Ａrg／ＮＯ系统变化可能是动脉粥样硬化的表现之一，其有可能成为动脉粥样硬化发生发展的检测指标。     

17 Beta-estradiol stimulates expression of endothelial and inducible NO synthase in rat myocardium in-vitro and in-vivo

OBJECTIVES: NO production has been attributed to play a major role in cardiac diseases such as cardiac hypertrophy and cardiac remodeling after myocardial infarction which display significant gender-based differences. Therefore we assessed the effect of 17 beta-estradiol (E2) on estrogen receptor (ER) alpha and beta and endothelial and inducible NO synthase in neonatal and adult rat cardiomyocytes. METHODS: The presence of ER alpha and ER beta was demonstrated by immunofluorescence and western blot analysis as well as the expression pattern of inducible NO synthase (iNOS) and endothelial NOS (eNOS) in isolated cardiomyocytes from neonatal and adult rats. Furthermore, regulation of myocardial iNOS and eNOS expression by estrogen was evaluated in the myocardium from ovariectomized or sham-operated adult Wistar-Kyoto rats. RESULTS: Incubation with E2 led to translocalization of the ER into the nucleus and increased receptor protein expression. E2 stimulated expression of iNOS and eNOS in both neonatal and adult cardiac myocytes. Coincubation with the pure anti-estrogen ICI 182,780 inhibited upregulation of ER and NOS expression. In ovariectomized rats myocardial iNOS and eNOS protein levels were significantly lower compared to sham-operated female animals. CONCLUSION: Taken together, these results show that E2 stimulates the expression of iNOS/eNOS in neonatal and adult cardiomyocytes in-vivo and in-vitro. These novel findings provide a potential mechanism of how estrogen may modulate NOS expression and NO formation in the myocardium.     

Co-expression and modulation of neuronal and endothelial nitric oxide synthase in human endothelial cells

Despite originally identified in neurones, the neuronal type of nitric oxide synthase (nNOS) is present also in cardiac and skeletal myocytes. Whether nNOS is functionally expressed in human endothelial cells--as the endothelial enzyme (eNOS)--is unknown. Human umbilical vein endothelial cells (HUVEC) were studied under control culture conditions and after 48 h treatment with cytomix (human tumour necrosis factor-alpha, interferon-gamma and E. coli endotoxin). We tested: (i) localisation and expression of nNOS and eNOS proteins by immunostaining and immunoblotting; (ii) activity of nNOS and eNOS by measuring L-arginine to L-citrulline conversion with 1-(2-trifluoromethylphenyl)imidazole (TRIM), a specific nNOS antagonist, in sub-cellular fractions; (iii) intracellular cGMP levels, as a marker for nitric oxide production, after TRIM pre-treatment, by radioimmunoassay. nNOS protein was expressed in the cytosolic fraction and immunolocalised in cultured HUVEC, and co-localised with the eNOS protein in frozen sections of the human umbilical cord. nNOS protein contributed to total L-citrulline production as TRIM selectively and dose-dependently reduced L-citrulline synthesis in the cytosolic but not particulate fraction of HUVEC. Similarly, TRIM reduced intracellular cGMP content both at baseline and after stimulation with a calcium ionophore. Cytomix down-regulated the expression and function of both nNOS and eNOS while no inducible NOS (iNOS) was detected. In conclusion, a functional neuronal type of NOS is co-expressed with the endothelial NOS type in HUVEC, suggesting a possible role for nNOS in regulation of blood flow.     

Overexpression of vasostatin-1 protects hypoxia/reoxygenation injuries in cardiomyocytes independent of endothelial cells

Introduction : Vasostatin‐1 (VS‐1) has been suggested in protecting hypoxia/reoxygenation (H/R) injuries in isolated hearts. However, the molecular mechanisms remained to be elucidated. Methods : Cardiomyocytes were treated with recombinant Ad‐VS‐1 adenoviral vector before H/R. Cell viability was studied using MTT methods and annexin V‐FITC flow cytometry. Intracellular oxidative stress was measured by superoxide dismutase (SOD) and malondialdehyde (MDA), and inflammatory reactions by enzyme‐linked immunosorbent assay (ELISA). Measurement of myocardial nitrous oxide synthase (NOS) was determined by serum nitric oxide (NO) concentrations using nitrite reductase and endothelial nitric oxide synthase (eNOS) by Western blotting. Inhibitors of the NOS system, including hemoglobin and KT5823, were applied to verify the results. Results: In comparison of the blank group, cardiac myocytes overexpressing VS‐1 showed significant decrease in apoptosis, intracellular oxidative stress, and inflammatory reactions (P < 0.05). In addition, serum NO concentrations and expression of eNOS were notably enhanced (P < 0.05). These protective effects of VS‐1 were suppressed in the presence of apoptosis‐inducing agents. Conclusions: Overexpression of VS‐1 in cardiomyocytes could limit the H/R injuries at molecular levels. The protective effects were independent of endothelial cell function, suggestive of a potential therapeutic target for patients with myocardial ischemia in the future.     

Comparison of nitric oxide production in response to carbachol between macrovascular and microvascular cardiac endothelial cells.

Cardiac microvascular endothelial cells (EC) play an important role in the physiological regulation of coronary blood flow, but their function has not been rigorously examined, because suitable in vitro models have not been available. Cardiac macrovascular and microvascular EC were isolated and cultured from 14-16-week-old Sprague-Dawley rats to examine the pharmacological responses of carbachol-induced nitric oxide (NO) production using a Griess method. Carbachol-induced NO production was only detected in cardiac macrovascular EC, which suggests that endothelial production of NO differs between macrovascular and microvascular EC. Next, cardiac microvascular EC was treated with either vehicle, angiotensin-converting enzyme (ACE) inhibitor (captopril, 10 micromol/L) or angiotensin II type 1 (AT1) receptor antagonist (CV11974, 10 micromol/L) for 4 days. Carbachol-induced NO production was improved by captopril (136+/-45nmol, p<0.01 vs vehicle) and CV11974 (146+/-30nmol, p<0.01 vs vehicle). Angiotensin II concentration in the culture medium and protein expressions of endothelial nitric oxide synthase and AT1 receptor in the EC were similar among the 3 groups. Interestingly, the level of muscarinic subtype 3 (M3) receptor was significantly increased in the EC treated with captopril (214%, p<0.01) and CV11974 (296%, p<0.01). When cardiac microvascular EC were treated with neomycin (non-selective phospholipase C inhibitor), carbachol-induced NO production was also improved (146+/-35nmol, p<0.01, neomycin I mmol/L) together with increased expression of M3 receptor (p<0.01). These data suggest that the upregulation of the M3 receptor by captopril or CV11974 occurs via a phospholipase C-dependent pathway. Cardiac microvascular EC also produced NO constitutively, as did the macrovascular EC, but carbachol-induced NO production was decreased. The present data suggest that the upregulation of the M3 receptor by the ACE inhibitor and AT1 receptor antagonist is a new beneficial effect of these drugs on microvascular endothelial function.     

内皮素在大鼠高血压心肌肥大中的作用

目的研究内皮素（ＥＴ）在一氧化氮合酶（ＮＯＳ）抑制剂亚硝基左旋精氨酸甲酯（Ｌ－ＮＡＭＥ）诱导的高血压心肌肥大中的作用及ＥＴＡ受体阻断剂ＪＫＣ－３０１的保护效应。方法复制大鼠Ｌ－ＮＡＭＥ高血压模型，动物分对照组、高血压组和ＪＫＣ－３０１治疗组，测定心重、血浆及心肌ＥＴ水平和心肌丝裂素活化蛋白激酶（ＭＡＰＫ）活性。结果高血压动物的心重、ＥＴ水平和心肌ＭＡＰＫ活性较对照组都显著升高（Ｐ＜０．０１或０．０５），加用ＪＫＣ－３０１治疗则较高血压组ＥＴ水平不变，但血压、心重和ＭＡＰＫ活性均降低（Ｐ＜０．０１或０．０５），心肌ＭＡＰＫ活性与左心室肥大程度呈正相关（ｒ＝０．８２，Ｐ＜０．０１）。结论一氧化氮缺乏的心肌肥大可能是由ＥＴ所介导的，ＥＴＡ受体阻断剂对此种肥大有防治作用     

氟对大鼠脑组织中一氧化氮合成酶活性的影响

目的为研究氟对神经系统的作用机理。方法利用化学发光分析技术测定大鼠脑组织中的一氧化氮合成酶的活性。结果氟暴露大鼠脑组织中ＮＯＳ活性明显高于对照组，直接在ＮＯＳ反应液中加入氟化钠，ＮＯＳ活性亦增加，而且这种增强作用能被一氧化氮合成酶的抑制剂Ｌ－硝基精氨酸所阻断。结论无论在体内还是体外，氟能使一氧化氮合成酶的活性增高。