Enhanced nitric oxide release during cortical spreading depression following infusion of glyceryl trinitrate in the anaesthetized cat

Intravenous infusion of glyceryl trinitrate (GTN) into migraineurs induces an immediate headache followed by migraine. We studied the effect of GTN 10.25 g kg¹ min ¹) on local cerebrovascular laser Doppler flux (rCBF_LDF), artery diameter and NO concentration (selective NO microelectrode) in the pial middle cerebral artery perfusion territory of the anaesthetized cat, at rest and during cortical spreading depression (SD). GTN infusion induced a significant increase in pial artery diameter, rCBF_LDF, and NO concentration. Following termination of infusion, NO concentrations remained significantly elevated above controls for 60 min, other parameters returned to baseliae within 10 min ( p 0.05, ANOVA, post hoc Dunnett's multiple comparison procedure). Two hours after termination of infusion KCl-evoked SD was initiated. GTN-treated animals exhibited significantly ( p 0.05, Kruskal-Wallis) elevated SD-induced NO release compared to controls. All other parameters remained unaffected. Our results demonstrate that GTN induces a prolonged increase in local NO concentrations and enhances SD-induced NO release.     

Repetitive cortical spreading depression in a gyrencephalic feline brain: inhibition by the novel benzoylamino-benzopyran SB-220453

Transient cortical depolarization is implicated in the pathology of migraine. SB-220453 is a potent anti-convulsant which inhibits neurogenic inflammation and cortical spreading depression (SD)-evoked nitric oxide release via a novel but unknown mechanism. This study further investigates the effects of SB-220453 on generation and propagation of repetitive SD in the anaesthetized cat. Vehicle or SB-220453 1, 3 or 10 mg/kg was administered intraperitoneally 90 min prior to induction of SD in the suprasylvian gyrus (SG). Changes in d.c. potential were recorded in the SG and the adjacent marginal gyrus (MG). In vehicle-treated animals (n = 7), a brief exposure (6 min) to KCl induced a median (25-75% range) number of five (four to six) and three (two to four) depolarizations over a duration of 55 min (32-59 min) and 51 min (34-58 min) in the SG and MG, respectively. SB-220453 produced dose-related inhibition of the number of events and period of repetitive SD activity. SB-220453 also reduced SD-induced repetitive pial vasodilatation but had no effect on resting haemodynamics. However, when SD events were observed in the presence of SB-220453, it had no effect on metabolic coupling. These results show that SB-220453 produces marked inhibition of repetitive SD in the anaesthetized cat. SB-220453 may therefore have therapeutic potential in treatment of SD-like activity in migraine.     

A double-blind study of SB-220453 (Tonerbasat) in the glyceryltrinitrate (GTN) model of migraine

The need for experimental migraine models increases as therapeutic options widen. In the present study, we investigated SB-220453 for efficacy in the glyceryltrinitrate (GTN) human experimental migraine model. SB-220453 is a novel benzopyran compound, which in animal models inhibits neurogenic inflammation, blocks propagation of spreading depression and inhibits trigeminal nerve ganglion stimulation-induced carotid vasodilatation. We included 15 patients with migraine without aura in a randomized double-blind crossover study. SB-220453 40 mg or placebo was followed by a 20-min GTN infusion. Headache, scored 0-10, was registered for 12 h, and fulfillment of International Headache Society (IHS) criteria was recorded until 24 h. Four subjects had a hypotensive episode after SB-220453 plus GTN but none after GTN alone. The reaction was unexpected, since animal models and previous human studies had shown no vascular or sympaticolytic activity with SB-220453. The study was terminated prematurely due to this interaction. GTN was consistent in producing headache and migraine that resembled the patients' usual spontaneous migraine. Nine patients had GTN on both study days. Peak headache score showed a trend towards reduction after SB-220453 compared with placebo (median 4 vs. 7, P = 0.15). However, no reduction was seen in the number of subjects experiencing delayed headache (8 vs. 8), number of subjects reporting migraine (6 vs. 8), migraine attacks fulfilling IHS criteria 1.1 or 1.7 (6 vs. 7) or IHS 1.1 alone (4 vs. 5). SB-220453 had no significant pre-emptive anti-migraine activity compared with placebo in this human model of migraine. Interaction between SB-220453 and GTN was discovered. This is important for the future development of the compound and underlines the usefulness of experimental migraine models.     

Nitric oxide synthase inhibition: a new principle in the treatment of migraine attacks

Glyceryl trinitrate, an exogenous nitric oxide (NO) donor, and histamine, which causes NO formation in vascular endothelium, have been shown to trigger migraine attacks. However, it remains uncertain whether NO is involved in the subsequent phase of migraine attacks. To answer this question we studied the effect of L-NGmethylarginine hydrochloride (546C88), a NO-synthase inhibitor, on spontaneous migraine attacks. In a double-blind study design, 18 patients with migraine without aura randomly received 546C88 (6 mg/kg) or placebo (5% dextrose) iv given over 15 mm for a single migraine attack (546C88 placebo, 15:3). Furthermore, 11 placebo-treated patients from previous double-blind trials with almost identical design were added to the placebo group in the statistical evaluation. Two hours after the infusion, 10 of 15 L -N^Gmethylarginine hydrochloride-treated patients experienced headache relief compared to 2 of 14 placebo-treated patients ( p =0.0l). Symptoms such as phono- and photophobia were also significantly improved. A similar trend for nausea was not significant. We conclude that NO may be involved in the pain mechanisms throughout the course of spontaneous migraine attacks.     

抑郁症患者血清一氧化氮及一氧化氮合成酶的检测及其临床研究

目的 探讨血清NO、一氧化氮合成酶(NOS)活力与抑郁症的关系.方法 纳入136例符合中国精神障碍分类与诊断标准的抑郁症患者(实验组)和120名健康志愿者(对照组),进行血清NO水平及NOS活力的检测,并进行对照分析.结果 实验组血清NO水平(70.05±10.34)μmol/L及NOS活力平均水平(29.49±5.12)U/L均高于正常对照组[(67.17±16.52)μmol/L、(26.99±2.87)U/L],差异均有统计学意义(P均<0.05);抑郁症患者中服药组血清NO水平(74.42±8.80)μmol/L及NOS活力平均水平(27.71±5.46)U/L均低于未服药组[(78.81±12.28)μmoL/L、(30.49±4.65)U/L],两者相比,差异有统计学意义(P均<0.05).结论 抑郁症患者血清NO水平及NOS活力升高,NO升高可能是抑郁症发病的影响因素;抗抑郁药可能通过降低血清NO水平而起到抗抑郁作用.     

芦荟多糖对体外培养人表皮细胞分泌细胞因子及一氧化氮的影响

目的研究芦荟多糖对体外培养人表皮细胞分泌细胞因子及一氧化氮(NO)的影响。方法测定经25、50、100、200和400mg/L,不同浓度芦荟多糖作用后的人表皮细胞培养上清液中转化生长因子-α(TGF-α)、TGF-β、白细胞介素-1β(IL-1β)、IL-6、IL-8、肿瘤坏死因子(TNF)及NO的水平;对照组则用等体积的细胞培养液处理。结果与对照组比较,经芦荟多糖作用后,培养液中TGF-α、TGF-β1、IL-1β、IL-6、IL-8和TNF水平呈不同程度升高,其差异有显著性(P<0.05或P<0.01);且随着芦荟多糖作用浓度的增加,其效应与剂量明显相关(P<0.01);而NO水平与对照组比较呈显著性下降(P<0.01),量-效关系明显(P<0.01)。结论芦荟多糖促进人表皮细胞分泌TGF-α、TGF-β1、IL-1β、IL-6、IL-8及TNF,而对NO释放则具有抑制作用。     

Hydroxocobalamin,a nitric oxide scavenger,in the prophylaxis of migraine: an open,pilot study

Drugs which directly counteract nitric oxide (NO), such as endothelial receptor blockers, NO-synthase inhibitors, and NO-scavengers, may be effective in the acute treatment of migraine, but are also likely to be effective in migraine prophylaxis. In the underlying pilot study the prophylactic effect of the NO scavenger hydroxocobalamin after intranasal administration in migraine was evaluated. Twenty patients, with a history of migraine of > 1 year and with two to eight migraine attacks per month, were included in an open trial. A baseline period was followed by an active treatment period of 3 months with 1 mg intranasal hydroxocobalamin daily. Patients were instructed to complete a diary in which details of each attack were described. A reduction in migraine attack frequency of >/ or = 50% was seen in 10 of 19 patients, which corresponds to 53% of the patients (responders). A reduction of > or = 30% was noted in 63% of the patients. The mean attack frequency in the total study population showed a reduction from 4.7 +/- 1.7 attacks per month to 2.7 +/- 1.6 (P < 0.001). For the responders the migraine attack frequency was reduced from 5.2 +/- 1.9 (baseline) to 1.9 +/- 1.3 attacks per month (P < 0.005), while for those who did not respond a non-significant reduction was found: 4.1 +/- 1.4 to 3.7 +/- 1.5 (P > 0.1). A reduction was also observed for the total duration of the migraine attacks per month, the total number of migraine days per month and the number of medication doses for acute treatment used per month. This is the first prospective, open study indicating that intranasal hydroxocobalamin may have a prophylactic effect in migraine. As a percentage of responders in prophylactic trials of > 35-40% is unlikely to be a placebo effect, a double-blind study is warranted.     

Cardiovascular bioimaging of nitric oxide: Achievements,challenges, and the future

Nitric oxide (NO) is a ubiquitous, volatile, cellular signaling molecule that operates across a wide physiological concentration range (pM–µM) in different tissues. It is a highly diffusible messenger and intermediate in various metabolic pathways. NO plays a pivotal role in maintaining optimum cardiovascular function, particularly by regulating vascular tone and blood flow. This review highlights the need for accurate, real‐time bioimaging of NO in clinical diagnostic, therapeutic, monitoring, and theranostic applications within the cardiovascular system. We summarize electrochemical, optical, and nanoscale sensors that allow measurement and imaging of NO, both directly and indirectly via surrogate measurements. The physical properties of NO render it difficult to accurately measure in tissues using direct methods. There are also significant limitations associated with the NO metabolites used as surrogates to indirectly estimate NO levels. All these factors added to significant variability in the measurement of NO using available methodology have led to a lack of sensors and imaging techniques of clinical applicability in relevant vascular pathologies such as atherosclerosis and ischemic heart disease. Challenges in applying current methods to biomedical and clinical translational research, including the wide physiological range of NO and limitations due to the characteristics and toxicity of the sensors are discussed, as are potential targets and modifications for future studies. The development of biocompatible nanoscale sensors for use in combination with existing clinical imaging modalities provides a feasible opportunity for bioimaging NO within the cardiovascular system.     

脊髓伤后脊髓组织中一氧化氮合酶活性变化与兴奋性氨基酸释放间的联系

目的探明脊髓伤后脊髓组织中一氧化氮合酶(NOS)活性变化与兴奋性氨基酸(EAA)释放间的关系.方法首先通过蛛网膜下腔注射谷氨酸(GLU)观测其对大鼠脊髓组织NOS活性动态变化的影响;然后通过微透析技术及高效液相色谱荧光法动态地探测不同NOS活性水平对伤段脊髓局部EAA含量变化的影响.结果外源性GLU迅速激活了脊髓组织NOS的活性,而抑制NOS活性则明显降低了伤段脊髓组织EAA的浓度.结论脊髓伤后脊髓组织中一氧化氮(NO)与EAA的释放相互促进,因而在继发性脊髓损伤中形成级联放大的神经毒性因子释放.     

Nitroglycerin-induced headache is not dependent on histamine release: support for a direct nociceptive action of nitric oxide

The molecular mechanisms of migraine pain have not yet been clarified. Monoamine and the peptide neurotransmitters involved in neurogenic inflammation do not cause significant head pain. Our previous studies of glyceryl trinitrate (GTN) and histamine-induced headaches have suggested that nitric oxide (NO) is the causative molecule in migraine pain. We furthermore suggest that substances capable of inducing experimental vascular headache do so via a common mediator which is NO. Finally, it is suggested that drugs exert their antimigraine activity by inhibiting NO or subsequent steps in the cascade of intracellular reactions triggered by NO. These novel observations change current views on vascular headache mechanisms and the importance of NO as an initiator of the migraine attacks dictates new approaches to the pharmacological treatment of migraine and other vascular headaches.     

Humming-induced release of nasal nitric oxide for assessment of sinus obstruction in allergic rhinitis: pilot study

BACKGROUND: Humming greatly increases nasal nitric oxide (NO) in healthy people by causing a rapid washout of NO from the sinuses. This increase is abolished in patients with complete sinus ostial obstruction. OBJECTIVE: Allergic rhinitis is a risk factor for development of sinusitis and we wanted to study whether nasal NO measurement during humming could be used to detect sinus abnormalities in this disorder. METHODS: Fifty-nine consecutive subjects with mild to moderate allergic rhinitis were studied. Their present nasal symptoms were recorded. Then NO levels were measured by chemiluminescence during quiet single-breath nasal exhalations and humming exhalations at a fixed exhalation flow of 0.2 L s(-1). Based on the NO results the patients were divided into two groups: those with a great increase in nasal NO during humming (humming responders, n = 46) and those without a significant increase (humming nonresponders, n = 13). In 11 of the nonresponders and in 22 of the responders the passage to the osteomeatal complex area was assessed and scored by nasal endoscopy. This was carried out by an oto-rhino-laryngologist unaware of the NO results. RESULTS: Among the nonresponders nine of 11 patients (80%) had endoscopic signs of bilateral sinus obstruction, compared with one of the 22 (< 5%) humming responders. Baseline nasal symptom score and NO levels during quiet exhalation were not significantly different between the groups CONCLUSION: Absence of a nasal NO peak during humming is associated with endoscopic findings suggestive of sinus ostial obstruction in subjects with allergic rhinitis. Measurement of nasal NO during humming may be a simple method to detect sinus abnormalities in these patients.     

内皮一氧化氮合酶基因多态性与糖尿病肾病关系的研究

目的 探讨内皮一氧化氮合酶(eNOS)基因内含子4的多态性与糖尿病肾病的关系,以及其在中国人、马来西亚人和印度人中的分布。方法 选择258例病程在10年以上的2型糖尿病患者作为观察对象,其中中国人150例、马来西亚人71例、印度人37例。从患者全血中提取DNA,然后,进行聚酶链反应(PCR)、克隆及测序。结果 以往认为该基因有2种等位基因(a和b),而本研究发现3种等位基因,并对第3种多态(等位基因c)基因进行了序列分析;统计分析显示,等位基因a、b和c均与糖尿病肾病无显著相关性。结论 eNOS基因内含子4上的多态性有3种等位基因;该基因多态性与糖尿病肾病无显著相关性。     

一氧化氮合酶在缺血预适应诱导第二心肌保护窗口中的作用

目的探讨一氧化氮合酶在缺血预适应诱导第二心肌保护窗口减少心肌梗死范围中的作用.方法结扎冠状动脉复制心肌缺血预适应及心肌梗死模型.斑点印迹法测定心肌热休克蛋白72含量.结果缺血预适应前静注一氧化氮合酶抑制剂(左旋硝基精氨酸)可使缺血预适应组的心肌梗死范围由(22.6±5.9)%扩大至(40.1±8.3)%,与对照组(44.2±8.1)%水平相似.亦可使缺血预适应诱导的心肌热休克蛋白72表达由3.3±0.8降至2.3±0.8,与对照组水平1.8±0.6相似.结论一氧化氮合酶在缺血预适应诱导第二心肌保护窗口过程中发挥重要作用.其作用可能与其参与诱导心肌热休克蛋白72表达有关.     

偏头痛患者血浆内皮素和一氧化氮含量的检测及其意义

目的：探讨血浆内皮素（ＥＴ）和一氧化氮（ＮＯ）含量变化在偏头痛发病中的临床意义。方法：采用经颅彩色多普勒超声（ＴＣＤ）检测具有典型脑动脉痉挛频谱表现的５０ 例偏头痛患者,测定其大脑部分动脉的收缩期血流速度（Ｖｓ）、舒张末期血流速度（Ｖｄ）和平均血流速度（Ｖｍ ）,大脑中动脉收缩峰血流速度（Ｖｓ ＭＣＡ）／颈内动脉颅外段收缩峰血流速度（Ｖｓ ＩＣＡ）以及血浆ＥＴ和ＮＯ含量,并与４０ 例健康体检者（正常对照组）作比较。结果：偏头痛组Ｖｓ〔（１３４７８±１０６８）ｃｍ ／ｓ〕、Ｖｄ〔（６３３９±５８８）ｃｍ ／ｓ〕、Ｖｍ 〔（９１３０±５５４）ｃｍ ／ｓ〕、Ｖｓ ＭＣＡ／Ｖｓ ＩＣＡ（２３２±０４４）和血浆ＥＴ〔（８２００±２５４５）ｎｇ／Ｌ〕均明显高于正常对照组〔（９１２２±１０２３）ｃｍ ／ｓ、（４６０３±６４３）ｃｍ ／ｓ、（６００３±９２９）ｃｍ ／ｓ、（１７０±０１２）和（６５７１±１１２３）ｎｇ／Ｌ,Ｐ均＜ ００１〕,血浆ＮＯ 含量〔（５６２５±２２２１）μｍ ｏｌ／Ｌ〕明显低于正常对照组〔（７４５２±２０１３）μｍ ｏｌ／Ｌ,Ｐ＜ ００１〕;且随着血管痉挛支数的增加,     

Effect of a nitric oxide donor on the ophthalmic artery flow velocity waveform in preeclamptic women.

OBJECTIVE: To evaluate the effects of an antihypertensive agent on the orbital circulation of preeclamptic women. METHODS: We studied the ophthalmic arteries of 10 healthy pregnant women and 10 women with severe preeclampsia by pulsed Doppler ultrasonography and evaluated the effect of transdermal isosorbide dinitrate, a nitric oxide donor, on preeclamptic women. RESULTS: The average pulsatility index and resistive index were significantly lower, whereas the average end-diastolic velocity, time-averaged mean peak velocity, and peak ratio, which quantifies characteristic changes in the ophthalmic artery flow velocity waveform, were higher in preeclamptic women. Transdermal isosorbide dinitrate significantly reduced the average end-diastolic velocity (P < .05) and peak ratio of the ophthalmic artery (P < .01), whereas it did not significantly affect other indices. CONCLUSIONS: Orbital circulation was altered in preeclamptic women. A nitric oxide donor affected orbital circulation. Peak ratio was a sensitive index for evaluating orbital circulation in preeclampsia.     

Effect of a nitric oxide donor (glyceryl trinitrate) on nociceptive thresholds in man

Several animal studies suggest that nitric oxide (NO) plays a role in central and peripheral modulation of nociception. Glyceryl trinitrate GTN) exerts its physiological actions via donation of NO. The purpose of the present study was to examine the effect of this NO donor on nociceptive thresholds in man. On two different study days separated by at least , week 12 healthy subjects received a staircase infusion of GTN (0.015, 0.25. 1.0 ,2.0 mg/kg/min. 20 min each dose) or placebo in a randomized double-blind crossover design. Before the infusion and after 15 min of infusion on each dose, pressure pain detection and tolerance thresholds were determined by pressure a gometry (Somomedic AB, Sweden) in three different anatomic regions (finger, a temporal region with interposed myofascial tissue and a temporal region without interposed myofascial tissue. Relative to placebo, the three higher GTN doses induced a decrease in both detection and tolerance thresholds in the temporal region with interposed myofascial tissue ( p =0.003 detection and p =0.002 tolerance threshold: Friedman). No such changes were observed in the other two stimulated regions. These results could reflect central facilitation of nociception by NO. However, we regard convergence, of nociceptive input from pericranial myofascial tissue and from cephalic blood vessels dilated by NO as a more likely, explanation of our findings.     

Increased luminal nitric oxide concentrations in the small intestine of patients with coeliac disease

BACKGROUND: Inflammation is known to be associated with enhanced nitric oxide production. A role for nitric oxide in coeliac disease has been suggested because of increased expression of the inducible isoform of nitric oxide synthase in the small intestine of patients with untreated coeliac disease. DESIGN: During small bowel endoscopy in 11 control subjects, 10 patients with untreated coeliac disease and seven patients with treated coeliac disease, gas was aspirated from different parts of the upper gastrointestinal tract and immediately analysed using a chemiluminescence technique. Luminal nitric oxide concentrations were also quantified in 13 control subjects who had undergone colonoscopy. RESULTS: Jejunal luminal nitric oxide concentrations were more than 20 times higher in patients with coeliac disease than in normal control subjects (mean 755 +/- 173 ppb, range 215-1690 ppb, vs. mean 31 +/- 9 ppb, range 1-83 ppb, P < 0.001). Jejunal luminal nitric oxide levels in patients with treated coeliac disease (mean 54 +/- 18 ppb, range 3-126 ppb) did not differ from those of control subjects. CONCLUSIONS: This study shows that intraluminal jejunal nitric oxide concentrations are significantly increased in patients with untreated active coeliac disease.     

北方汉族人eNOS第四内含子a/b基因多态性与原发性高血压的关系

目的探讨内皮型一氧化氮合酶(eNOS)第四内含子27bp插入/缺失(a/b)多态性与北方汉族人群原发性高血压(EH)的关系。方法应用多聚酶链反应(PCR)检测207例EH患者和231名健康人eNOS基因型,测定血清一氧化氮合酶(NOS)活性和一氧化氮代谢物(NOx)水平。结果健康人aa、ab和bb基因型为0.43%、13.42%和86.15%,而EH组分别为0.49%、19.32%和80.19%;EH组a等位基因的频率为10.15%高于健康对照组的7.14%(P<0.05)。EH组血浆NO含量降低(P<0.05),TNOS活性和iNOS活性下降(P<0.05),eNOS活性较健康对照组有降低趋势,但无显著性差异(P>0.05)。结论EH患者血浆NOS活性和NO水平降低,eNOS基因变异,27bp(a/b)多态性对内皮NO释放有一定影响,a等位基因可能是中国汉族人EH的遗传标志。     

超敏C反应蛋白、一氧化氮与急性高血压性脑出血关系的研究

目的 探讨超敏C反应蛋白(hs-CRP)和一氧化氮(NO)在急性高血压性脑出血患者炎症状态及预后判断中的作用.方法 采用颗粒增强免疫透射比浊法、硝酸还原酶法分别测定126例急性高血压性脑出血患者血清hs-CRP和NO水平,并与120例健康者进行比较.结果 急性高血压性脑出血患者血清hs-CRP[(26.89±17.13)mg/L]和NO[(67.15±14.66)μmol/L]水平均明显高于健康对照组[(1.48±0.91)mg/L和(33.05±6.11)μmol/L](P<0.01).与预后佳组比较,预后不佳组血清hs-CRP[(45.73±17.03)mg/L]和NO[(83.15±7.75)μmol/L]水平升高更为明显(P<0.01).结论 hs-CRP和NO是介导急性高血压性脑出血患者高炎性状态和继发性脑损害的关键效应分子.血清hs-CRP和NO水平的高低与患者的预后有关.     

Endothelial nitric oxide synthase (NOS) is upregulated in rapid progressive pulmonary hypertension of the newborn

Objective To provide evidence for the upregulation of endothelial nitric oxide synthase (eNOS) or inducible nitric oxide synthase (iNOS) in the assumed imbalance in the pathophysiology of rapid progressive pulmonary hypertension of the newborn (RPPHN), which is characterized by abnormal hypertrophy of the pulmonary arterioles and arteries leading to increased pulmonary vascular resistance. Furthermore, to determine the cellular source and topographic distribution of eNOS and iNOS.Material and Methods Lung biopsies were taken from two term neonates with clinical and echocardiographic evidence of RPPH and of three controls. Biopsies were obtained at an early stage of the disease as well as at post mortem and examined immunohistochemically for the presence of eNOS, iNOS and nitrotyrosine.Results The endothelial cells of pulmonary arterioles stained significantly for eNOS protein in RPPHN patients. This was not the case in the control infants. There were no differences for nitrotyrosine or iNOS between RPPHN patients and controls.Conclusion Rapid progressive pulmonary hypertension of the newborn leads to compensatory induction of eNOS synthesis specifically in endothelial cells of the pulmonary arterioles. This mechanism of compensation can lead to delayed presentation of RPPHN during the late neonatal period. Exogenous inhaled nitric oxide therapy does not lead to suppression of the endogenous synthesis of nitric oxide.