丹参桃芎汤对肝纤维化小鼠腹膜淋巴孔的调控与尿钠离子浓度变化的影响

目的寻找治疗肝硬变腹水的有效方药.方法具有腹膜淋巴孔调控作用的丹参配合活血化瘀的桃仁、川芎组成丹参桃芎汤对肝纤维化造模小鼠进行腹膜淋巴孔调控与尿离子浓度变化的实验,并经扫描电镜和计算机图像处理与定量分析.结果预防组、治疗组腹膜淋巴孔孔径、密度与模型组、对照组比较有非常显著性差异(P＜0.001),而尿离子测定,治疗组不及预防组.结论丹参桃芎汤是治疗腹水的有效方剂.     

中药治疗肺结核的用药规律及其核心药物作用机制的探讨

目的: 基于数据挖掘,探讨中药治疗肺结核的用药规律,挖掘出其常用药对,并借助网络药理学探讨其核心药物对肺结核的作用机制。方法: 对符合纳入标准的中药复方建立数据库,运用Apriori算法建立起关联模型,通过中药系统药理分析平台数据库筛选核心药对的活性成分和靶点,应用Gene Cards数据库检索肺结核疾病靶点,分析得到药物-疾病共同靶点,将靶点输入String数据库获得蛋白相互作用网络,通过DAVID数据库进行GO和KEGG通路富集分析,并利用Cytoscape软件对成分-靶点-信号通路进行可视化。结果: 筛选出符合要求的文献156篇,涉及272味中药,频次排名前5位的中药为百部(113次)、麦冬(104次)、黄芪(89次)、白及(86次)、地黄(83次)。关联分析后显示,白及、百部关联性最高(支持度:71.81%,置信度:80.99%,提升比:1.28)。对白及-百部药对进行网络药理学分析,白及-百部发挥的主要作用可能与癌症、乙型肝炎、结核病、凋亡、MAPK、TNF等相关信号通路有关(P值均<0.01)。结论: 通过数据挖掘,白及-百部为治疗肺结核的核心药对。网络药理学初步阐明核心药对白及-百部治疗肺结核的作用机制,可为临床新方组合和新药研发提供思路。     

Effect of emodin and sandostatin on metabolism of eicosanoids in acute necrotizing pancreatitis

INTRODUCTION In order to study the therapeutic mechanisms of emodin, an extract of Rhubarb (Rhizoma et Radix Rhei, a traditional Chinese herbal medicine), and sandostatin in the treatment of acute necrotizing pancreatitis (ANP), we used the two drugs in rat models of the disease and observed the changes of plasma thromboxane-2 (TXB2),6-ketoprostaglandin F1α (6-keto-PGF1α) and prostaglandin E2 (PEG2).     

Salt loading on plasma asymmetrical dimethylarginine and the protective role of potassium supplement in normotensive salt-sensitive asians

Asymmetrical dimethylarginine (ADMA) is an endogenous inhibitor of NO synthase. Because endothelial NO pathway is compromised in patients with salt-sensitive hypertension, we investigated whether the plasma ADMA can be modulated by chronic salt loading in normotensive salt-sensitive persons and its relationship with NO, and we further determined whether or not dietary potassium supplementation can reverse them. Sixty normotensive subjects (aged 20 to 60 years) were selected from a rural community of Northern China. All of the people were sequentially maintained on a low-salt diet for 7 days (3 g/day, NaCl), then a high-salt diet for 7 days (18 g/day), and high-salt diet with potassium supplementation for another 7 days (4.5 g/day, KCl). After salt loading, the plasma ADMA concentrations increased significantly in salt-sensitive subjects (0.89+/-0.02 micromol/L versus 0.51+/-0.02 micromol/L; P<0.05), whereas the plasma NOx levels reduced considerably (41.8+/-2.1 micromol/L versus 63.5+/-2.1 micromol/L; P<0.01). All of the abnormalities normalized when dietary potassium were supplemented (0.52+/-0.03 micromol/L versus 0.89+/-0.02 micromol/L for ADMA and 58.1+/-0.9 micromol/L versus 41.8+/-2.1 micromol/L for NOx). Statistically significant correlations were found among plasma ADMA level, the mean blood pressure, and the level of NO after salt loading in normotensive salt sensitive individuals. Our study indicates that high dietary potassium intake reduces blood pressure and ADMA levels while increasing NO bioactivity in normotensive salt-sensitive but not salt-resistant Asian subjects after salt loading.     

Carvedilol action is dependent on endogenous production of nitric oxide

BACKGROUND: Carvedilol is known to be an adrenoreceptor blocker and free radical scavenger, used in hypertension and cardiac failure. However, its therapeutic actions cannot be fully explained by these mechanisms. In these studies, we tested the hypothesis that carvedilol action is associated with the synthesis/release of nitric oxide (NO). METHODS: Male Wistar rats (n = 22), 9 weeks old, were anesthetized with an intraperitoneal injection of sodium pentobarbital. Mean arterial pressure and arterial NO levels were monitored throughout the experiments. Carvedilol (1 mg/kg, intravenously [iv]) effects were evaluated before and after NO synthase (NOS) inhibitor N(omega)-nitro-L-arginine methyl ester (L-NAME, 5 mg/kg, iv). RESULTS: Carvedilol induced a significant decrease in basal arterial pressure (from 126.6 +/- 4.3 mm Hg to 75.9 +/- 3.0 mm Hg, P < .001) and significant increase in NO levels (from 17.9 +/- 1.7 micromol/L to 32.2 +/- 2.5 micromol/L, P < .001). After administration of L-NAME the arterial pressure increased (129.9 +/- 5.0 mm Hg, P < .001) with concomitant decrease in NO levels (13.4 +/- 1.6 micromol/L, P < .01). The second carvedilol administration (post-L-NAME) did not affect either arterial pressure (108.3 +/- 8.0 mm Hg) or NO levels (22.1 +/- 1.3 micromol/L). CONCLUSIONS: Our results suggest that the carvedilol-induced decrease of blood pressure is associated with an increase of plasma NO levels. Furthermore, NOS inhibition results in impairment of carvedilol hemodynamic effects and plasma NO levels. Therefore, these results are consistent with the hypothesis that the hemodynamic effect of carvedilol is in part dependent on endogenous NO production.     

Mobilization of malignant ascites with diuretics is dependent on ascitic fluid characteristics.

Serial ascites and plasma volumes were measured during diuresis in nine patients with ascites caused by peritoneal carcinomatosis, four patients with chylous malignant ascites, and three patients with portal hypertension-related ascites caused by massive hepatic metastases. Oral diuretics were given to achieve an adequate natriuresis on a sodium-restricted diet. During the study period (7.8 +/- 3.2 days), patients with peritoneal carcinomatosis and chylous ascites lost 0.49 +/- 0.31 and 0.51 +/- 0.42 kg/day in weight, respectively, with negligible change in ascites volumes (-0.03 +/- 0.11 and 0.02 +/- 0.09 L/day). Patients with ascites caused by massive hepatic metastasis lost 1.06 +/- 0.15 kg/day in weight (P = 0.01 for massive hepatic metastasis vs. peritoneal carcinomatosis) and 0.23 +/- 0.13 L/day of ascites (P less than 0.05 vs. other groups). Plasma volume changes were not significantly different among the three groups. Patients with edema (9/16) had a greater natriuresis and daily weight loss. Three patients with peritoneal carcinomatosis and one with chylous ascites developed renal dysfunction or symptomatic hypotension. No patient with massive hepatic metastasis developed these complications. In patients with ascites caused by peritoneal carcinomatosis or chylous malignant ascites there is no mobilization of ascites, whereas in patients with massive hepatic metastasis, ascites may be mobilized with diuretics.     

Increased intestinal macromolecular permeability and urine nitrite excretion associated with liver cirrhosis with ascites

AIM： To determine intestinal permeability, the serum tumor necrosis factor （TNF）-α level and urine nitric oxide （NO） metabolites are altered in liver cirrhosis （LC） with or without ascites. METHODS： Fifty-three patients with LC and 26 healthy control subjects were enrolled in the study. The intestinal permeability value is expressed as the percentage of polyethylene glycol （PEG） 400 and 3350 retrieval in 8-h urine samples as determined by high performance liquid chromatography. Serum TNF-α concentrations and urine NO metabolites were determined using an enzyme-linked immunosorbent assay （ELISA） and Greiss reaction method, respectively. RESULTS： The intestinal permeability index wassignificantly higher in patients with LC with ascites than in healthy control subjects or patients with LC without ascites （0.88 ± 0.12 vs 0.52 ± 0.05 or 0.53 ± 0.03, P 〈 0.05） and correlated with urine nitrite excretion （r = 0.98）. Interestingly, the serum TNF-α concentration was significantly higher in LC without ascites than in control subjects or in LC with ascites （198.9 ± 55.8 pg/mL vs 40.9 ± 12.3 pg/mL or 32.1 ± 13.3 pg/mL, P 〈 0.05）. Urine nitrite excretion was significantly higher in LC with ascites than in the control subjects or in LC without ascites（ 1170.9± 28.7 μmol/L vs 903.1 ± 55.1 μmol/L or 956.7 ± 47.7 μmol/L, P 〈 0.05）. COMCLUSIOM： Increased intestinal macromolecular permeability and NO is probably of importance in the pathophysiology and progression of LC with ascites, but the serum TNF-α concentration was not related to LC with ascites.     

Interaction between beta-adrenergic receptor stimulation and nitric oxide release on tissue perfusion and metabolism

Nitric oxide (NO) may be an important modulator of sympathetic tone. We used im and sc microdialysis in humans to characterize the interaction of NO synthase inhibition and adrenoreceptor stimulation on tissue perfusion, metabolism, and norepinephrine release. Microdialysis probes were perfused with L- or D-nitro-L-arginine-methyl-ester (100 micromol/L) followed by incremental doses of isoproterenol, epinephrine, or nitroprusside. Blood flow was estimated based on the ethanol dilution technique. In muscle, the increase in blood flow with isoproterenol was abolished by L-NAME. The ethanol ratio was 0.03 +/- 0.011 with D-NAME and 0.075 +/- 0.014 with L-NAME during isoproterenol treatment (1 micromol/L). The effect was less pronounced in adipose tissue. The vasodilatory effect of nitroprusside was similar with D- and L-NAME. L-NAME augmented isoproterenol- and epinephrine-induced glycerol release. Dialysate glycerol during 1 micromol/L isoproterenol was 47 +/- 6.7 micromol/L with D-NAME and 72 +/- 15 micromol/L with L-NAME. In skeletal muscle, dialysate norepinephrine during 1 micromol/L isoproterenol treatment was 0.73 +/- 0.17 and 1.3 +/- 0.15 nmol/L with D- and L-NAME, respectively. We conclude that NO synthase inhibition attenuates beta(2)-adrenoreceptor-mediated vasodilation and enhances beta-adrenoreceptor-mediated lipolysis. These effects are in part mediated through an increase in interstitial norepinephrine concentrations. The data are consistent with the idea that in humans, NO is important in modulating and ameliorating sympathetic effects in peripheral tissues.     

Activation of distinct cAMP-dependent and cGMP-dependent pathways by nitric oxide in cardiac myocytes.

Nitric oxide (NO) donors were recently shown to produce biphasic contractile effects in cardiac tissue, with augmentation at low NO levels and depression at high NO levels. We examined the subcellular mechanisms involved in the opposing effects of NO on cardiac contraction and investigated whether NO modulates contraction exclusively via guanylyl cyclase (GC) activation or whether some contribution occurs via cGMP/PKG-independent mechanisms, in indo 1-loaded adult cardiac myocytes. Whereas a high concentration of the NO donor S-nitroso-N-acetylpenicillamine (SNAP, 100 micromol/L) significantly attenuated contraction amplitude by 24.4+/-4.5% (without changing the Ca2+ transient or total cAMP), a low concentration of SNAP (1 micromol/L) significantly increased contraction amplitude (38+/-10%), Ca2+ transient (26+/-10%), and cAMP levels (from 6.2 to 8.5 pmol/mg of protein). The negative contractile response of 100 micromol/L SNAP was completely abolished in the presence of the specific blocker of PKG KT 5823 (1 micromol/L); the positive contractile response of 1 micromol/L SNAP persisted, despite the presence of the selective inhibitor of GC 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ, 10 micromol/L) alone, but was completely abolished in the presence of ODQ plus the specific inhibitory cAMP analog Rp-8-CPT-cAMPS (100 micromol/L), as well as by the NO scavenger oxyhemoglobin. Parallel experiments in cell suspensions showed significant increases in adenylyl cyclase (AC) activity at low concentrations (0.1 to 1 micromol/L) of SNAP (AC, 18% to 20% above basal activity). We conclude that NO can regulate both AC and GC in cardiac myocytes. High levels of NO induce large increases in cGMP and a negative inotropic effect mediated by a PKG-dependent reduction in myofilament responsiveness to Ca2+. Low levels of NO increase cAMP, at least in part, by a novel cGMP-independent activation of AC and induce a positive contractile response.     

Tubulovascular nitric oxide crosstalk: buffering of angiotensin II-induced medullary vasoconstriction

Studies were designed to determine the source of NO responsible for buffering of the angiotensin II (Ang II)-mediated decrease of blood flow in the renal medulla. Intracellular Ca2+ concentration ([Ca2+]i) and NO production ([NO]i) of pericytes and endothelium of the vasa recta were independently measured with the use of fura 2-AM and 4,5-diaminofluorescein diacetate (DAF-2DA), respectively, in microtissue strips of the vascular bundles of the outer medullary vasa recta. Disruption of the endothelium of the vasa recta by perfusion with latex microspheres enabled imaging of the pericytes. Ang II (1 micromol/L) produced an increase of [NO]i of 19+/-6 U in pericytes of the vasa recta when the vessels were adjacent to medullary thick ascending limbs (mTALs). Pericytes of isolated vasa recta without surrounding mTALs showed a rapid peak increase in [Ca2+]i of 248+/-107 nmol/L, with a sustained elevation of 107+/-75 nmol/L, but did not show an increase in [NO]i to either Ang II (1 micromol/L) or the Ca2+ ionophore 4-bromo-A23187 (5 micromol/L). These observations indicated the lack of Ang II and Ca2+-sensitive NO production in pericytes of the vasa recta. In isolated vasa recta with intact endothelium, Ang II reduced [Ca2+]i from 128+/-28 to 62+/-13 nmol/L and failed to increase [NO]i. However, the Ca2+ ionophore did increase [NO]i in the endothelium (47+/-8 U), indicating the presence of Ca2+-sensitive NO production. Significant increases of [NO]i were observed in single isolated mTALs in response to both Ang II (33+/-6 U) and the Ca2+ ionophore (51+/-18 U). We conclude that Ang II increases [Ca2+]i in pericytes of the descending vasa recta as part of its constrictor action and that this vasoconstriction is buffered by the NO from the surrounding tubular elements, such as mTALs.     

苯扎贝特对牛主动脉内皮细胞一氧化氮合酶基因表达的影响及其机制的研究

目的研究过氧化物酶体增生物激活受体α(peroxisomeproliferator-activatedreceptoralpha,PPARα)的配体苯扎贝特对原代牛主动脉内皮细胞(bovineaortaendothelialcells,BAEC)一氧化氮合酶(endothelialnitricoxidesynthase,eNOS)基因表达的影响并探讨其机制。方法分离和培养牛主动脉内皮细胞,采用Northern印迹法、Western印迹法检测苯扎贝特对BAECeNOSmRNA和蛋白质表达的影响,采用定量PCR的方法及NO试剂盒检测苯扎贝特对eNOSmRNA半衰期及NO产生的影响;继而采用Western印迹法,给予不同的信号转导通路抑制剂研究苯扎贝特影响eNOS表达所通过的信号转导途径,此外,构建了由人eNOS启动子驱动的荧光报告基因,研究苯扎贝特对eNOS启动子活性的影响。结果苯扎贝特以浓度(50~200μmol/L)依赖的方式明显上调BAEC细胞eNOS的mRNA和蛋白质表达(P<0.05),并促进一氧化氮(nitricoxide,NO)的生成[对照组(14.97±1.29)μmol/L,苯扎贝特不同浓度组(25.12±1.25)μmol/L,(30.12±1.85)μmol/L,(33.47±1.22)μmol/L],增强eNOS-ser-1179位点的磷酸化表达(P<0.05),但是对eNOS-thr-497位点的磷酸化表达几乎没有抑制作用,定量PCR证实苯扎贝特增加eNOSmRNA的半衰期(从3.1~6.1h),进一步的研究显示苯扎贝特以浓度依赖的方式增加人eNOS启动子驱动的荧光报告基因的荧光活性(相对的荧光活性在100μmol/L和200μmol/L组分别为4429.43±391.41,6187.5±307.53,对照组为3361.81±316.85),增加磷酸化丝裂原激活的蛋白激酶(mitogen-activatedproteinkinase,MAPK)的蛋白质表达(P<0.05及P<0.01),而PPARα、磷脂酰肌醇3-激酶(phosphatidylinositol3-kinase,PI3K)和MAPK抑制剂可明显逆转苯扎贝特对eNOS表达的上调作用(P<0.01)。结论苯扎贝特通过上调eNOS的蛋白质表达、促进eNOS的磷酸化、增强eNOS的转录及eNOSmRNA的稳定性,从而促进NO的生成,其效应的发挥既通过依赖于PPARα的方式,也可以经MAPK和PI3K信号通路介导的不依赖于PPARα的“非基因效应”,揭示了PPARα的配基苯扎贝特的降脂外作用包括抗动脉粥样硬化和抗高血压的可能作用机制。     

Ascites Adenosine Deaminase Activity is Decreased in Tuberculous Ascites with Low Protein Content

The value of adenosine deaminase activity (ADA) in ascitic fluid was examined in 12 patients with confirmed peritoneal tuberculosis and compared with that of 96 patients with ascites of other different etiologies as an age-matched control group, to determine the diagnostic value of the ADA activity in tuberculous ascites. The mean adenosine deaminase activity (ADA) value in ascitic fluid of the tuberculous peritonitis group was 47.9 +/- 21.9 IU/L and in the control group 9.6 +/- 5 U/L (mean +/- SD); p less than 0.01. A different method than that usually reported in tuberculous peritonitis was used for ascites ADA estimation. The best sensitivity and specificity was obtained when greater than 32 U/L was used as a cutoff point. The ascites ADA activity correlated with the ascites total protein concentration in the tuberculosis group (r = 0.842). Our findings confirm other results and support the ADA activity determination in ascitic fluid as a useful noninvasive screening test in the diagnosis of peritoneal tuberculosis in endemic areas or in high risk patients. However, false-negative results may occur in those patients in which ascites total protein concentration is low.     

Extracellular ATP stimulates NO production in rat thick ascending limb

NO produced by NO synthase (NOS) 3 acts as an autacoid to regulate NaCl absorption in the thick ascending limb. ATP induces NO production by NOS 3 in endothelial cells. We hypothesized that extracellular ATP activates NOS in thick ascending limbs through P2 receptors. To test this, we measured intracellular NO production using the NO-selective fluorescent dye DAF-2 in suspensions of rat medullary thick ascending limbs. We found that ATP increased DAF-2 fluorescence in a concentration-dependent manner, reaching saturation at &200 micromol/L with an EC50 of 37 micromol/L. The increase was blunted by 74% by the nonselective NOS inhibitor L-omega-nitro-arginine-methyl-ester (2 mmol/L; 60+/-7 versus 16+/-6 arbitrary fluorescence units; P<0.02; n=5). In the presence of the P2 receptor antagonist suramin (300 micromol/L), ATP-induced NO production was reduced by 64% (101+/-11 versus 37+/-5 arbitrary fluorescence units; P<0.002; n=5). Blocking ATP hydrolysis with a 5'-ectonucleotidase inhibitor, ARL67156 (30 micromol/L) enhanced the response to ATP and shifted the EC(50) to 0.8 micromol/L. In the presence of ARL67156, the EC50 of the P2X-selective agonist beta,gamma-methylene-adenosine 5'-triphosphate was 4.8 micromol/L and the EC50 for the P2Y-selective agonist UTP was 40.4 micromol/L. The maximal responses for both agonists were similar. Taken together, these data indicate that ATP stimulates NO production in the thick ascending limb primarily through P2X receptor activation and that ATP hydrolysis may regulate NO production.     

Elevated ascitic fluid fibronectin concentration. A non-specific finding

Ascitic fluid fibronectin concentration was measured in 111 specimens by laser nephelometry. Sterile, portal hypertension-related fluid fibronectin concentration (24 +/- 14 micrograms/ml) was significantly lower than the concentration in infected, portal hypertension-related ascites (49 +/- 44 micrograms/ml, P less than 0.001), peritoneal carcinomatosis (123 +/- 45 micrograms/ml, P less than 0.001), massive liver metastases-related ascites (55 +/- 21 micrograms/ml, P less than 0.001), as well as in ascites of other types (94 +/- 42 micrograms/ml, P less than 0.001). The percentage of samples with fibronectin concentration, greater than 75 micrograms/ml, was 0% for sterile, portal hypertension-related ascites, 28% for infected, portal hypertension-related ascites, 89% for peritoneal carcinomatosis, 20% for massive liver metastases-related ascites, and 72% for ascites of other types. Ascitic fluid fibronectin concentration correlated in a linear fashion with ascitic fluid total protein (r = 0.81, P less than 0.001). Fibronectin concentration in ascites appears to be elevated under a variety of conditions and does not appear to be a specific marker for cancer.     

Altered pressure-natriuresis in obese Zucker rats.

It has not been examined whether the pressure-natriuresis response is altered in the insulin-resistant condition. Furthermore, despite an important role of nitric oxide (NO) in modulating pressure-natriuresis, no investigations have been conducted assessing the renal interstitial NO production in insulin resistance. The present study examined whether pressure-natriuresis was altered in insulin-resistant obese Zucker rats (OZ) and assessed the cortical and medullary nitrate/nitrite (NOx) levels with the use of the renal microdialysis technique. In OZ, serum insulin/glucose ratio (23.0+/-4.0x10(-8), n=9) and blood pressure (119+/-3 mm Hg) were greater than those in lean Zucker rats (LZ; 7.0+/-1.9x10(-8) and 103+/-4 mm Hg, n=9). The pressure-natriuresis curve in OZ was shifted to higher renal perfusion pressure (RPP), and the slope was blunted compared with that in LZ (0.073+/-0.015 vs 0.217+/-0.047 microEq/min kidney weight/mm Hg, P<0.05). The basal renal NOx level was reduced in OZ (cortex, 4.032+/-0.331 micromol/L; medulla, 4. 329+/-0.515 micromol/L) compared with that in LZ (cortex, 7.315+/-1. 102 micromol/L; medulla: 7.698+/-0.964 micromol/L). Furthermore, elevating RPP increased the medullary NOx in LZ, but this pressure-induced response was lost in OZ. Four-week treatment with troglitazone, an insulin-sensitizing agent, improved hyperinsulinemia, systemic hypertension, and basal renal NOx levels (cortex, 5.639+/-0.286 micromol/L; medulla, 5.978+/-0.284 micromol/L), and partially ameliorated the pressure-natriuresis curves; the slope of pressure-natriuresis curves and elevated RPP-induced NOx, however, were not corrected. In conclusion, our study suggests that insulin resistance is closely associated with abnormal pressure-natriuresis and hypertension. These deranged renal responses to insulin resistance are most likely attributed to impaired medullary NO production within the medulla.     

基于数据挖掘探讨徐浩教授治疗冠心病的用药规律

目的分析徐浩教授治疗冠心病的处方用药规律和经验。方法从门诊病历中选取并整理徐浩教授治疗冠心病处方543首,提取中药处方数据,建立标准化医案数据库,利用古今医案云平台系统的用药统计分析、聚类分析、复杂网络分析等数据挖掘功能,分析医案中处方的用药频次、性味归经、常用药对及核心处方等数据。结果整理处方543首,涉及药物217种,治疗冠心病的高频中药有黄芪、丹参、柴胡、炙甘草、三七粉、瓜蒌等,药性多属温、微寒、平,药味多属甘、苦味,主要归经为肝、肺、心经,功效以活血祛瘀、利水消肿、生津养血为主。常用药对有黄芪-丹参、丹参-黄芪、黄芪-三七粉等。聚类分析可将药物分为4类,分别为活血祛瘀止痛,调畅气机,宣痹通阳,益气养血、健脾化痰。复杂网络分析得出核心药物为黄芪、丹参、三七粉、瓜蒌、柴胡、黄芩、炙甘草、天麻、枳壳、制何首乌、党参、延胡索、川芎、薤白。结论徐浩教授治疗冠心病药物多为温、平、甘、苦,归肝、肺、心经,治疗多气血同治、寒热同调、虚实兼顾、注重调神,以温阳补气、活血化瘀、理气化痰、安神定志为法。     

Central hypotensive action of clonidine requires nitric oxide

Background- Clonidine has an antihypertensive effect by its action in the brain and, because we observed that the tonic production of nitric oxide (NO) in the brain is required to maintain blood pressure at its low, normotensive level, the current study was designed to determine whether the hypotensive action of clonidine resulted from its stimulation of excess NO in the brain. Methods and Results- Porphyritic microsensors were used to quantify NO concentration in the nucleus tractus solitarius (NTS) in vitro in brain slices and in vivo in the anesthetized rat. In both preparations, the basal production of NO in the NTS was 15+/-3 nmol/L. In vitro stimulation of the NTS with clonidine (50 nmol/L) resulted in an increase in the NO concentration to 84+/-7 nmol/L. In vivo, the intracerebroventricular (ICV) infusion of clonidine (0.03 microgram) caused an increase in NO concentration in the NTS to 128+/-17 nmol/L. This ICV injection of clonidine caused a fall in mean arterial pressure of -22+/-1 mm Hg and a decrease of heart rate of -18+/-2%. The blockade of NO production with N(G)-nitro-L-arginine-methyl ester (2 micromol; delivered ICV, 30 minutes before the clonidine) reduced responses to clonidine for both mean arterial pressure and heart rate (-3+/-1 mm Hg and -2+/-1% change, respectively). Conclusion- The stimulation of the release of NO in the brain by clonidine contributes to its central antihypertensive action.     

Serum concentrations of nitric oxide, tumor necrosis factor (TNF)-alpha and TNF soluble receptors in women with overweight and obesity

The aims of the present study was to examine how overweight and obesity affect serum concentrations nitric oxide (NO) metabolites and to determine whether there is association between serum concentrations tumor necrosis factor (TNF)-alpha and TNF soluble receptors (sTNF-R) in subjects with overweight and obesity. The study groups involved 154 women: 102 obese (81 obese with body mass index [BMI] 30 to 40 kg/m2 and 21 obese with BMI > 40 kg/m2), 24 overweight patients, and 28 lean controls. Serum concentrations of NO metabolites and of TNF-alpha and its soluble receptors (sTNF-R1, sTNFR-2) were measured by enzyme-linked immunosorbent assay (ELISA) kits. Serum concentration of insulin was measured by radioimmunoassay (RIA). Plasma glucose, cholesterol, high-density lipoprotein (HDL)-cholesterol, and triglicerydes were determined by enzymatic procedure. Body composition was determined by impedance analysis using Bodystat (Douglas, British Isles). Serum concentrations of NO in the overweight group (35.1 +/- 12.1 micromol/L) and the obese groups with BMI 30 to 40 kg/m2 (32.8 +/- 9.3 micromol/L) and with BMI greater than 40 kg/m2 (33.3 +/- 8.5 micromol/L) were significantly higher when compared to controls (28.2 +/- 8.1 micromol/L): P < .05; P < .01, and P < .01, respectively. There was no difference in levels of NO between the overweight group and both obese groups. Serum concentration of TNF-alpha was also significantly higher in the group with overweight (6.5 +/- 3.1 pg/mL), in the obese group with BMI 30 to 40 kg/m2 (6.8 +/- 3.1 pg/mL), and in the obese group with BMI greater than 40 kg/m2 (7.4 +/- 2.6 pg/mL) when compared to controls (2.9 +/- 2.2 pg/mL): P < .00005; P < .00005, and P < .0000001, respectively. However, serum concentrations of sTNF-R1 and -R2 did not differ significantly between the overweight group, both obese groups, and controls. In conclusion, we observed increased serum concentrations of TNF-alpha and NO in overweight and obese women. It seems that there is an association between serum concentrations of TNF-alpha and NO; however, this relationship depends on the degree of obesity.