静滴L—精氨酸对原发性高血压影响的研究

从血流动力学及神经内分泌学两方面探讨左旋精氨酸（Ｌ－Ａｒｇ）－一氧化氮（ｎｉｔｒｉｃｏｘｉｄｅ，ＮＯ）通路对原发性高血压的影响。方法２６例高血压病人分为两组，一组静滴Ｌ－Ａｒｇ，一组静滴生理盐水，观察其血压、心率及心功能的变化，同时检测血中ＮＯ、ｃＧＭＰ、肾上腺素（Ｅ）、去甲肾上腺素（ＮＥ）以探讨其降压机理。结果在Ｌ－Ａｒｇ静注期间，病人血压下降，心率增快，心输出量（ＣＯ）、每搏输出量（ＳＶ）、射血分数（ＥＦ）增加，总外周阻力（ＴＰＲ）降低，ＮＯ的标志物ｃＧＭＰ升高。而在滴注６０＇时，随着ｃＧＭＰ浓度的降低，ＣＯ、ＳＶ、ＥＦ也随之降低，而ＴＰＲ复又回升。Ｅ、ＮＥ、Ｎｉｔｒｉｔｅ及Ｎｉｔｒａｔｅ在静滴前后无显著性改变。结论Ｌ－Ａｒｇ通过使ｃＧＭＰ浓度升高，引起明显的血流动力学改变；Ｌ－Ａｒｇ可能抑制血压过低所致的反应性Ｅ及ＮＥ的升高作用。     

胰岛素抵抗高血压大鼠血小板L—精氨酸／一氧化氮系统的改变

目的 观察胰岛素抵抗高血压大鼠血小板Ｌ－精氨酸／一氧化氮系统的改变。方法 自发性高血压大鼠（ＳＨＲ）自第５周至第１０周喂信果糖,制备胰岛素抵抗高血压大鼠（ＩＲ）模型。在此模型上,检测血小板一氧化氮合酶（ＮＯＳ）活性、一氧化氮（ＮＯ）产生量及Ｌ－精氨酸（Ｌ－Ａｒｇ）转运特征,同时观察了血浆Ｌ－Ａｒｇ水平、心纳素（ＮＡＰ）、ＮＯ水平及ｃＧＭＰ水平。结果 ＳＨＲ大鼠收缩压（ＳＢＰ）（Ｐ〈０．０１）,血浆     

肝硬化大鼠动脉组织一氧化氮合酶活性

材料与方法：经皮下注射ＣＣ１４制备肝硬化大鼠模型。动脉组织中组织型ＮＯＳ（。ＮＯＳ）及诱生型ＮＯＳ（ｉＮＯＳ）活性，以不同条件下测定组织匀浆中３Ｈ－Ｌ一精氨酸转化生成的３Ｈ－Ｌ一瓜氨酸量计算。ＣＧＭＰ含量使用放免法测定。结果：肝硬化大鼠动脉一氧化氮台酶（ＮＯＳ）、ｃＮＯＳ、ｉＮＯＳ活性、ｃＧＭＰ含量较正常对照显著增加。肝硬化动脉ＮＯＳ活性与环磷酸鸟苷（ＣＧＭＰ）量呈正相关（表１）。讨论：我们以前曾发现，ＮＯＳ阻滞剂可纠正肝硬化大鼠的外周动脉扩张，并使肝硬化大鼠离体主动脉环对缩血管物质的低反应性有…     

急性心肌梗塞患者红细胞左旋精氨酸-一氧化氮途径的变化

目的：探讨急性心肌梗塞患者红细胞在旋精氨酸—一氧化氮（Ｌ－Ａｒｇ－ＮＯ）途径变化及临床意义。 方法：１４例急性心肌梗塞患者为急性心肌梗塞组,１０例健康成人为正常对照组,取静脉抗凝血,分离并提纯红细胞,同位素标记法测定~３Ｈ标记左旋精氨酸（~３Ｈ－Ｌ－Ａｒｇ）的转运动力学;分离统化一氧化氮合酶（ＮＯＳ）后测定其含量及活性,放射免疫法测定红细胞环磷酸鸟苷（ｃＧＭＰ）含量。 结果：急性心肌梗塞组患者红细胞①Ｌ－Ａｒｇ的总转运及Ｙ~＋载体的最大转运速率（Ｖｍａｘ）分别较正常对照组降低１４％（Ｐ＜０．０５）及 １８％（Ｐ＜０．０１）,米氏常数（Ｋｍ）分别增加３２％及 ４６％（Ｐ＜０．０１）;Ｙ＋Ｌ载体无改变。②ＮＯＳ含量及活性分别较正常对照组降低１３％（Ｐ＜０．０５）及４４％（Ｐ＜０．０１）。③ＣＧＭＰ含量较正常对照组下降２７％（Ｐ＜０．０５）。 结论：急性心肌梗塞患者红细胞Ｌ－Ａｒｇ－ＮＯ途径存在多环节功能障碍,导致一氧化氮（ＮＯ）生成减少,可能会促进急性心肌梗塞的进展。     

同型半胱氨酸对正常人血小板L-精氨酸/一氧化氮途径的影响

目的通过观察同型半胱氨酸（Ｈｃｙ）对血小板Ｌ精氨酸（ＬＡｒｇ）／一氧化氮（ＮＯ）系统的影响,探讨Ｈｃｙ对血小板损伤的机制。方法健康成人６例,平均年龄（３３±７）岁。晨取静脉血,将每例血样分为对照组及加Ｈｃｙ组,分别测定血小板ＬＡｒｇ转运功能;同时将上述两组分别设立加乙酰胆碱（Ａｃｈ）与不加Ａｃｈ组,测定血小板ＮＯ合酶（ＮＯＳ）活性、ＮＯ生成量和ｃＧＭＰ含量。结果（１）在不同浓度的Ｌ－Ａｒｇ时,Ｈｃｙ组ＬＡｒｇ转运速率均低于对照组（Ｐ＜００１）。（２）在Ａｃｈ刺激下,ＮＯＳ活性明显提高,但Ｈｃｙ组提高的程度明显低于对照组（Ｐ＜００１）。（３）在Ａｃｈ刺激下,ＮＯ生成及ｃＧＭＰ含量明显提高（Ｐ＜００１）,但Ｈｃｙ组仍明显低于对照组（Ｐ＜００５）。结论Ｈｃｙ影响血小板功能可能与ＬＡｒｇ／ＮＯ系统改变有关。     

高血压病人血小板L—精氨酸／一氧化氮系统的改变

目的原发性高血压（ＥＨ）病人（２３例）与健康成年人（１４）例作对照，观察高血压时血小板（Ｐｔ）左旋精氨酸（Ｌ－Ａｒｇ）－一氧化氮（ＮＯ）系统的改变及Ｌ－Ａｒｇ转运的特征。方法微盘测定法测定血小板孵育液中亚硝酸盐（ＮＯ２－）的含量来反映ＮＯ产生量、ＡＤＰ刺激下ＮＯ的产生量；采用张新波等建立的一氧化氮合酶（ＮＯＳ）测定改良法测定血小板ＮＯＳ活性；放射性同位素标记测定血小板３Ｈ－Ｌ－Ａｒｇ转运的动力学特征。结果ＥＨ患者Ｐｔ的ＮＯ产生量及ＮＯＳ活性较对照组明显降低（Ｐ＜０．０１），用ＡＤＰ刺激后，ＥＨ患者Ｐｔ的ＮＯ增加量仅为正常对照组增加量的６０％，其Ｌ－Ａｒｇ转运能力亦显著低于正常人（各浓度点Ｐ均＜０．０１）。最大转运速率（Ｖｍａｘ）仅为正常人的７９％（Ｐ＜０．０１），而米氏常数（Ｋｍ）则无明显改变（Ｐ＞０．０５）。结论高血压时Ｐｔ的Ｌ－Ａｒｇ－ＮＯ系统存在明显异常，提示对ＥＨ患者，在降压的同时，联合应用改善Ｌ－Ａｒｇ－ＮＯ系统的药物，对预防和治疗高血压减少并发症可能会有更好的效果。     

吸入L—精氨酸对哮喘豚鼠气道反应性的影响

吸入Ｌ－精氨酸对哮喘豚鼠气道反应性的影响张建勇朱惠如钱梓文一氧化氮（ＮＯ）是一种新的信使分子，参与气道反应性的调节，Ｌ－精氨酸（Ｌ－Ａｒｇ）是体内ＮＯ合成的前体。本研究通过测定肺阻力（ＲＬ）与肺顺应性（ＣＬ），旨在观察吸入Ｌ－Ａｒｇ对清醒状态哮喘豚鼠...     

胃黏膜对阿司匹林适应性的实验研究

目的 探讨胃黏膜对阿司匹林的适应性及其发生机制。方法 连续数天经胃管给大鼠灌入酸化阿司区林（ａｃｉｄｉｆｉｅｄ ａｓｐｉｒｉｎ,ＡＳＡ）,计算胃黏膜损伤面积和损伤深度。用ＲＩＡ法检测胃黏膜组织内ＥＧＦ的含量。为观察一氧化氮（ＮＯ）在胃黏膜对ＡＳＡ适应性中的 应用ＡＳＡ前３０ｍｉｎ经大鼠性静脉分另注入Ｌ－精氨酸（Ａｒｇ）、Ｌ－ＮＡＭＥ及Ｌ－Ａｒｇ＋ＬＮＡＭＥ,观察胃黏膜损伤面积及深度。结果 初次应用     

左旋精氨酸：一氧化氮通路与高血压

左旋精氨酸：一氧化氮通路与高血压成都市第三人民医院张大红刘晓平综述燕纯伯吴发琼审校左旋精氨酸（Ｌ－Ａｒｇ）在一氧化氮合酶（ＮＯｓｙｎｔｈｅｔａｓｅ，ＮＯＳ）的催化作用下生成一氧化氮（ＮＯ）这一生化过程，其英文名称为：Ｌ－ａｒｇｉｎｉｎｅ－ＮＯｐａｔｈ...     

人类高血压与内皮功能

１８６５年生理学家Ｈｉｓ首先提出内皮（Ｅｎｄｏｔｈｅｌｉ－ｕｍ）这一概念,其研究历史可概况如下：１９７６年Ｖａｎｅ发现内皮细胞合成并分泌前列腺素Ｉ２（ＰＧＩ２）,１９８０年Ｆｕｒｃｈｇｏｔｅ首先提出内皮依赖性舒张因子（Ｅｎｄｏｔｈｅｌｉ－ｕｍｄｅｒｉｖｅｄｒｅｌａｘｉｎｇｆａｃｔｏｒ;ＥＤＲＦ）的概念。１９８７年Ｐａｌｍｅｒ和Ｌｇａｒｒｏ提出ＥＤＲＦ为一氧化氮（ＮＯ）样物质,并发现左旋精氨酸（Ｌ－Ａｒｇｉｎｉｎｅ;Ｌ－Ａｒｇ）为ＮＯ前体。１９９３年证明ＮＯ的舒张作用由环鸟苷酸（ｃＧＭＰ）介导完成…     

L-arginine stimulates cyclic guanosine 3',5'-monophosphate formation in rat islets of Langerhans and RINm5F insulinoma cells: evidence for L-arginine:nitric oxide synthase.

L-Arginine (L-Arg) is metabolized by nitric oxide synthase to the reactive intermediate nitric oxide. Since nitric oxide stimulates guanylyl cyclase and cGMP synthesis, L-Arg effects on cGMP accumulation in isolated pancreatic islets of the rat and RINm5F insulinoma cells were determined. Both L-Arg and glucose stimulation increased islet cGMP levels, and glucose potentiated the response to L-Arg alone. A competitive inhibitor of L-Arg metabolism to nitric oxide, NG-monomethyl-L-arginine, reduced glucose- and L-Arg-stimulated insulin release and glucose-induced increases in cGMP; however, basal insulin release was slightly increased. D-Arg and L-ornithine did not affect islet cGMP levels, although insulin release was stimulated. RINm5F cell cGMP levels and insulin release increased in response to L-Arg in a concentration- and time-related manner, whereas glucose and L-histidine were without effect. 8-Bromo-cGMP also slightly increased RINm5F cell insulin release. Sodium nitroprusside as a source of nitric oxide increased RINm5F cell cGMP production. Methylene blue and LY83583, inhibitors of soluble guanylyl cyclase activation, reduced RINm5F cell cGMP levels in the presence and absence of L-Arg; LY83583 also reduced glucose-stimulated cGMP levels in islets. Insulin release by glucose and L-Arg was also inhibited by methylene blue and LY83583 in islets. We conclude that glucose and L-Arg stimulate guanylyl cyclase activity and cGMP formation in beta-cells at least in part through metabolism to the reactive intermediate nitric oxide. However, neither nitric oxide nor cGMP synthesis is obligatory for insulin secretion.     

Nitric oxide in cyclosporine A-induced hypertension: role of protein kinase C

Chronic treatment with cyclosporine A (CsA), an immunosuppressive agent, causes hypertension. The effect of CsA on vascular responses was determined in Sprague-Dawley rats and isolated rat aortic rings. Male rats weighing 250 to 300 g were given either CsA (25 mg/kg/day) in olive oil or vehicle by intraperitoneal injection for 7 days. Cyclosporine A administration produced a 42% increase (P < .001) in mean arterial pressure (MAP), which reached a plateau after 3 days. Conversely, the level of both nitrate/nitrite (NO₂/NO₃), metabolites of nitric oxide (NO), and 3′, 5′ cyclic guanosine monophosphate (cGMP), which mediates NO action, decreased by 50% (P < .001) and 35% (P < .001), respectively, in the urine. Thoracic aortic rings from rats treated with CsA, and precontracted with endothelin (10⁻⁹ mol/L), showed a 35% increase (P < .001) in tension, whereas acetylcholine-induced (Ach; 10⁻⁹ mol/L) endothelium-dependent relaxation was inhibited 65% (P < .001) compared with untreated rats. This response was similar to that of aortic rings, denuded of endothelium, from untreated rats in which Ach-induced relaxation was completely abolished (P < .001). Ach-induced formation of both NO₂/NO₃ and cGMP by both denuded and CsA-treated aortic rings was inhibited 95% (P < .001) and 65% P < .001), respectively, compared with intact aortic rings. The effects of CsA were reversed both in vivo and in vitro by pretreatment with l-arginine (L-Arg; 10 mg/kg/day intraperitoneally), the precursor of NO. There were no changes in MAP and tension in rats treated with L-Arg alone. In addition, in the aorta of rats that were treated intraperitoneally with CsA for 7 days, CsA significantly activated protein kinase C (PKC) translocation and decreased NO₂/NO₃ production. This suggest that PKC mediates, in part, CsA-induced hypertension. In summary, CsA activates PKC, which inhibits endothelial NO formation, with resulting increases in MAP and tension, and this inhibition can be overcome by L-Arg administration.     

Reduced cGMP signaling associated with neointimal proliferation and vascular dysfunction in late-stage atherosclerosis

Atherosclerosis is associated with alterations in nitric oxide (NO)/cGMP signaling. In early stages of the disease, inflammatory and possibly other cells produce reactive oxygen species that scavenge vasoprotective NO. In addition to the oxidative stress, expression and activity of enzymes downstream to NO formation may also be affected. Here, we show in the aortas of chronically hypercholesterolemic rabbits (a model of late-stage atherosclerosis), both subunits and specific activity of the NO receptor soluble guanylyl cyclase (sGC) were significantly reduced, whereas overall NO synthase activity was unaffected. These changes were most prominent in the neointimal layer, wherein cGMP-dependent protein kinase I (cGK) levels also were reduced. Additionally, a protein (p38(nt)) that was constitutively tyrosine-nitrated was detected, and its expression was significantly reduced in atherosclerotic aorta. Phosphorylation of the cGK substrate vasodilator-stimulated phosphoprotein (VASP) at Ser-239, an established biochemical endpoint of NO/cGMP signaling, also was reduced. Thus, late-stage atherosclerosis is associated not only with enhanced NO breakdown but also with altered NO reception and cGMP signaling. Preferential down-regulation in neointima suggests a direct connection of these changes to neointimal proliferation and vascular dysfunction and provides a rationale for future pharmacotherapy using classical and novel sGC activators.     

Endothelium-derived relaxing factor from pulmonary artery and vein possesses pharmacologic and chemical properties identical to those of nitric oxide radical

The objective of this study was to elucidate the close similarity in properties between endothelium-derived relaxing factor (EDRF) and nitric oxide radical (NO). Whenever possible, a comparison was also made between arterial and venous EDRF. In vascular relaxation experiments, acetylcholine and bradykinin were used as endothelium-dependent relaxants of isolated rings of bovine intrapulmonary artery and vein, respectively, and NO was used to relax endothelium-denuded rings. Oxyhemoglobin produced virtually identical concentration-dependent inhibitory effects on both endothelium-dependent and NO-elicited relaxation. Oxyhemoglobin and oxymyoglobin lowered cyclic guanosine monophosphate (cGMP) levels, increased tone in unrubbed artery and vein, and abolished the marked accumulation of vascular cGMP caused both by endothelium-dependent relaxants and by NO. The marked inhibitory effects of oxyhemoglobin on arterial and venous relaxant responses and cGMP accumulation as well as its contractile effects were abolished or reversed by carbon monoxide. These observations indicate that EDRF and NO possess identical properties in their interactions with oxyhemoproteins. Both EDRF from artery and vein and NO activated purified soluble guanylate cyclase by heme-dependent mechanisms, thereby revealing an additional similarity in heme interactions. Spectrophotometric analysis disclosed that the characteristic shift in the Soret peak for hemoglobin produced by NO was also produced by an endothelium-derived factor released from washed aortic endothelial cells by acetylcholine or A23187. Pyrogallol, via the action of superoxide anion, markedly inhibited the spectral shifts, relaxant effects, and cGMP accumulating actions produced by both EDRF and NO. Superoxide dismutase enhanced the relaxant and cGMP accumulating effects of both EDRF and NO. Thus, EDRF and NO are inactivated by superoxide in a closely similar manner. We conclude, therefore, that EDRF from artery and vein is either NO or a chemically related radical species.     

Nitric oxide as a signal in thyroid.

It is now well established that agonist activation of the PIP2/calcium cascade in the thyroid results in the enhancement of cGMP accumulation presumably by activation of the soluble guanylate cyclase. In many tissues the physiological signal controlling soluble guanylate cyclase is nitric oxide (NO) and its synthesis from arginine is controlled by the intracellular Ca2+. In this report we show results that suggest that NO may be the intermediate of the cGMP response to the activation of the PIP2/calcium cascade. In dog thyroid slices, incubation with carbamylcholine or A23187 increases significantly free intracellular Ca2+ levels and the cGMP content of the slices. NG-Monomethyl-L-arginine (NMMA), a competitive inhibitor of arginine for nitric oxide synthase, inhibited these cGMP responses but not the action of sodium nitroprusside which activates soluble guanylate cyclase directly. The inhibition was relieved by arginine. Methylene blue, which blocks the activation of soluble guanylate cyclase by NO, also decreased the three stimulatory effects. NMMA and methylene blue also decreased the basal levels of cGMP. NO may therefore be an important autocrine and paracrine factor in thyroid.     

Glutathione reverses endothelial dysfunction and improves nitric oxide bioavailability.

OBJECTIVES: We investigated whether glutathione (GSH), a reduced thiol that modulates redox state and forms adducts of nitric oxide (NO), improves endothelium-dependent vasomotion and NO activity in atherosclerosis. BACKGROUND: Endothelial dysfunction and reduced NO activity are associated with atherosclerosis and its clinical manifestations such as unstable angina. METHODS: In the femoral circulation of 17 patients with atherosclerosis or its risk factors, endothelium-dependent vasodilation with acetylcholine (ACH), and endothelium-independent vasodilation with nitroglycerin and sodium nitroprusside were studied before and after GSH. In 10 patients, femoral vein plasma cyclic guanylate monophosphate (cGMP) levels were measured during an infusion of ACH before and after GSH. Femoral artery flow velocity was measured using a Doppler flow wire and the resistance index (FVRI) calculated as mean arterial pressure divided by flow velocity. RESULTS: Glutathione strongly potentiated ACH-mediated vasodilation; at the two doses, FVRI decreased by 47% and 56% before, and by 61% and 67% after GSH (p = 0.003). Glutathione also elevated cGMP levels in the femoral vein during ACH infusion from 17.6 +/- 3 to 23.3 +/- 3 pmol/ml (p = 0.006). Augmentation of ACH responses was only observed in patients with depressed endothelial function. Glutathione did not influence endothelium-independent vasodilation with either NO donor. CONCLUSIONS: Thiol supplementation with GSH selectively improves human endothelial dysfunction by enhancing NO activity.     

L-arginine administration reduces neointima formation after stent injury in rats by a nitric oxide-mediated mechanism

The clinical outcome of vascular stenting is limited by in-stent stenosis. Increased nitric oxide (NO)/cGMP signaling by L-arginine (L-Arg) supplementation, the substrate for NO synthase (NOS), or NOS gene transfer may reduce in-stent neointima formation. After stenting, vascular cell proliferation in rat carotid arteries, as measured by 5'-bromodeoxyuridine (5'-BrdU) incorporation, indicated 15+/-8%, 28+/-5%, and 33+/-7% 5'-BrdU-positive vascular cells at 4, 7, and 14 days, respectively. Reporter beta-galactosidase gene transfer efficacy was evidenced by 30% beta-galactosidase-expressing medial smooth muscle cells at 14 days. The intima-to-media ratio (I/M) progressively increased to 2.32+/-0.24 at 14 days. To target in-stent neointima formation, animals were infected with adenoviral vectors (4x10(10) plaque-forming units per mL) expressing NOS2 (AdNOS2) or no transgene (AdRR5), or they received daily doses of L-Arg (500 mg. kg(-1). (d-1) IP). The neointima at 14 days was smaller in L-Arg-treated than in untreated rats (I/M 1.25+/-0.35 vs 2.32+/-0.24, P<0.05, n=7 each) or in AdRR5- and AdNOS2-infected rats (I/M 2.57+/-0.43, n=7 and 1.82+/-0.75, n=8, respectively; P<0.05 for both). The effect of L-Arg was abolished by simultaneous administration of N(G)-nitro L-arginine methyl ester, an NOS inhibitor (2.03+/-0.39, P<0.05, vs L-Arg). Inflammation was markedly less in L-Arg- and AdNOS2-treated than in AdRR5-infected rats. Supplemental L-Arg reduces neointima formation after stenting by way of an NOS-dependent mechanism and may be a valuable strategy to target in-stent stenosis.     

肝细胞一氧化氮合酶的诱导及动力学研究

目的对内毒素和几种细胞因子诱导肝细胞一氧化氮合酶的协同效应及酶动力学参数进行研究.方法原位预灌流和段原酶循环灌流大鼠肝脏、分离肝实质细胞,观察内毒素、IFN-Y、IFN-α、TNFα、IL-lβ、IL-6及不同组合对肝细胞一氧化氮合酶活性、cGMP及NO2-+NO3的影响,分析酶动力学特征及皮质甾与酶诱导的量效关系.结果内毒素+IFN-v+TNFα+IL-lβ(IL-6)组合诱导酶表达效应最显著;酶参数分析显示Km、Vmax分别为108μmol/L和2632pmol@min1mg-1蛋白质,竞争性抑制剂L-NMMA、L-NNA作用的Ki分别为056μmolL及094μmol/L;诱导时间进程显示iNOS活性表达在9h达到峰值,但cGMP及NO2-NO3-的释放持续增加可维持至l8h;地塞米松和氢化可的松抑制肝细胞酶诱导的IC50分别为35×10-8mol/L和26×10-0mol/L.结论肝细胞诱导性一氧化氮合酶的表达依赖特异多细胞因子协同作用,这种可诱导性特征可能在内毒素血症和败血症休克发病机制中具有重要意义.     

植物雌激素α-玉米赤霉醇内皮依赖性舒张效应的机制研究

目的探讨植物雌激素α-玉米赤霉醇(α-ZAL)对大鼠胸主动脉环内皮依赖性舒张效应中一氧化氮合酶(NOS)-NO-环磷酸鸟苷(cGMP)系统的作用。方法采用体外血管环灌流的方法,先用10-6mol/L苯肾上腺素预收缩血管。观察10-10～10-5mol/L6个不同浓度α-ZAL对内皮完整和去除内皮的大鼠胸主动脉环的舒张作用。α-ZAL10-10～10-8mol/L为低浓度组,α-ZAL10-7～10-5mol/L为高浓度组,0.1%乙醇浓度为对照组。在高浓度组中分别预先加用10-5mol/L左旋硝基精氨酸甲酯(L-NAME组)和亚甲蓝(MB组)并观察其影响,测定动脉环中内皮型一氧化氮合酶(eNOS)和cGMP含量及灌流液中NO含量变化。结果L-NAME组和MB组均可减弱高浓度组中α-ZAL的内皮依赖性胸主动脉环舒张作用(P<0.05,P<0.01);与对照组比较,高浓度组胸主动脉环中eNOS、cGMP含量及灌流液中NO含量增高(P<0.05,P<0.01);与高浓度组比较,L-NAME组可降低灌流液中NO含量及胸主动脉环中cGMP含量(P<0.05,P<0.01);MB组可降低胸主动脉环中cGMP含量(P<0.01)。结论α-ZAL的内皮依赖性舒张作用与NOS-NO-cGMP系统的激活有关。     

Basal release of nitric oxide from aortic rings is greater in female rabbits than in male rabbits: implications for atherosclerosis.

Estradiol is known to exert a protective effect against the development of atherosclerosis, but the mechanism of this hormonal action is unknown. One of the early events in the development of atherosclerosis is the adhesion of macrophages to endothelial cells, and nitric oxide (NO) inhibits this process. We show that basal release of NO is greater with endothelium-intact aortic rings from female rabbits than those from males. Oophorectomy diminishes both circulating estradiol concentration and basal release of NO to levels seen in male rabbits. These data establish that basal NO release from endothelium-intact aortic rings depends on circulating estradiol concentration and offer an explanation for the protective effect of estradiol against the development of atherosclerosis.