大鼠对氟西泮抗痫耐受和依赖时海马中一氧化氮合酶的变化

目的通过测定大鼠对氟西泮抗痫耐受性和依赖性时海马中一氧化氮合酶(NOS)蛋白表达及活性的变化,探讨一氧化氮(NO)在此过程中可能的作用。方法建立大鼠对氟西泮抗痫耐受性和依赖性的模型。运用免疫印迹及免疫组化法检测海马中NOS蛋白表达,以及比色法检测NOS活性的变化。结果大鼠对氟西泮抗痫耐受组的海马中NOS蛋白表达明显高于对照组;而对氟西泮抗痫依赖组则与对照组差别无统计学意义。两组NOS活性均显著高于各自的对照组。结论NO可能是介导氟西泮抗痫耐受性和依赖性的因素之一。     

四逆汤对失血性休克家兔一氧化氮（NO）和一氧化氮合酶（NOS）的影响

目的：探讨中药四逆汤对失血性休克家兔一氧化氮的影响。方法：采用动物分组对照实验，测量不同状态下动物血浆一氧化氮和一氧化氮合酶(NOS)的变化。结果：与休克前比较，休克组的家兔血浆一氧化氮水平各时段均明显提高(P＜0．01)，而治疗组仅在治疗后30min家兔一氧化氮及NOS水平明显提高(P＜0．01)，其他时段与休克前比较，未见显著差异(P＜0．01)，且休克后lh、4h、8h休克组一氧化氮水平显著高于治疗组(P＜0．01)。经药物治疗的失血性休克家兔血浆一氧化氮水平明显降低。     

丹酚酸B对鸡胚绒毛尿囊膜血管新生作用的影响

目的探讨丹酚酸B对鸡胚绒毛尿囊膜血管新生的影响。方法将7日龄鸡胚制备鸡胚绒毛尿囊膜(chick embryo chorioallantoic membrane,CAM)模型,随机分为6个组,分别为PBS(phosphatebuffer solution)对照组,丹酚酸B 4个剂量组(150、50、16.67、5.56 mg.L-1)及VEGF(vascular endo-thelial growth factor)组,培养3 d后时采集数据进行评价。结果丹酚酸B 150、50 mg.L-1组血管新生面积明显高于PBS(phosphate buffer solution)对照组(P<0.01,P<0.05)。结论丹酚酸B可明显促进鸡胚绒毛尿囊膜血管新生。     

Constitutive nitric oxide synthases in the heart from hypertrophy to failure

1. Endogenous myocardial nitric oxide (NO) may modulate the transition from adaptive to maladaptive hypertrophy leading to heart failure. This review summarizes the information on the interrelations between the precise localization of NO synthases (NOS) and their regulatory functions within different compartments of the heart. 2. In rodent models of pressure overload or myocardial infarction, the three NOS isoforms (NOS1, NOS2, NOS3) were shown to play a neutral, protective, or even adverse role in myocardial remodelling, depending on the NOS activity, the location of each NOS and their regulators. 3. The analysis of conditions that modulate the expression of NOS1 and NOS3 in the heart according to physiopathological situations, indicated that, beside the level of total NOS activity, unique changes in NO compartmentation secondary to NOS1 or NOS3 subcellular location might be involved in the development of cardiac hypertrophy and failure. 4. Thus, different circuits in NO-signalling pathways in myocardium might be activated and this principle is a key to understand contradictions existing in NO biology in the heart. Unravelling the mechanisms behind the NO, NOS and cardiac function is still an ongoing challenge.     

Role of nitric oxide produced by constitutive and inducible nitric oxide synthases in the mouse gastric fundus

In the present study, the role of nitric oxide (NO) produced by constitutive and inducible nitric oxide synthases (cNOS and iNOS, resepctively) on the contraction and relaxation of fundus in normal and lipopolysaccharide (LPS)-treated mice was examined. A whole fundic ring isolated from mice pretreated with reserpine was mounted in an organ bath containing Krebs' solution with 0.001 mmol/L atropine. Rings were contracted initially by 5-hydroxytryptamine (5-HT; 0.03 mmol/L) before relaxation was induced using ATP (0.03 mmol/L), ADP (0.03 mmol/L), pentoxifylline (0.002 mmol/L), electrical field stimulation (EFS; 50 V, 1 msec, 50 Hz, 3 min) and L-arginine (0.05 mmol/L). All drugs and EFS induced significant relaxation of isolated rings. The relaxations induced were significantly inhibited by N(G)-nitro-L-arginine methyl ester (L-NAME; 1.0 mmol/L). However, the iNOS inhibitors L-N(6)-(1-iminoethyl) lysine hydrochloride (L-NIL; 1.0 mmol/L) and amino guanidine (AMG; 1.0 mmol/L) had no significant effect on tissue relaxation. Then, the relaxant effects of 0.03 mmol/L ATP were tested on precontracted isolated fundic rings taken from 10 mg/kg LPS-treated animals. The non-selective NOS inhibitor L-NAME (10 mg/kg), the iNOS inhibitors L-NIL (3 mg/kg) and AMG (20 mg/kg) and betamethasone (0.1 mg/kg) were used to examine the role of NO produced by iNOS in the relaxation responses. It was found that the level of contraction induced by 0.03 mmol/L 5-HT in rings isolated from LPS-treated animals was significantly (P < 0.5) less than that in rings from untreated mice. However, precontracted tissues from LPS-treated mice were significantly relaxed by ATP and the relaxation response to ATP was significantly inhibited by L-NIL, ANG and betamethasone, but not by L-NAME. We suggest that, in LPS-treated mice, the production of NO from iNOS produces a reduction in the contractile response, as well as a decrease in NO formation by cNOS, resulting in changes to smooth muscle cell function.     

Role of nitric oxide in allergic inflammation and bronchial hyperresponsiveness

The role of nitric oxide (NO) in allergic inflammation and bronchial hyperresponsiveness is unclear. We studied a selective prodrug nitric oxide synthase (NOS)-2 inhibitor, L-N(6)-(1-iminoethyl)lysine 5-tetrazole amide (SC-51). In ovalbumin-sensitized and challenged rats, exhaled NO levels increased by 3 h following challenge (3.73 +/- 0.74 ppb; P < 0.05), peaking at 9 h (11.0 +/- 2.75; P < 0.01) compared to saline controls (1.87 +/- 0.26; P < 0.05 and 2.81 +/- 0.18; P < 0.01). Immunoreactive lung NOS2 expression was increased in ovalbumin-challenged rats compared with ovalbumin-sensitized, saline-challenged rats at 8 h post-challenge. SC-51 (10 mg/kg; p.o.) inhibited allergen-induced increase in exhaled NO levels to 1.3 +/- 0.17 ppb. SC-51 inhibited bronchial hyperresponsiveness in ovalbumin-sensitized and challenged rats (P < 0.05). In sensitized non-exposed rats, SC-51 increased bronchial responsiveness (P < 0.05). SC-51 reduced the allergen-induced increase in bronchoalveolar lavage neutrophils, but caused a nonsignificant reduction in bronchial mucosal eosinophil numbers. NO generated through NOS2 contributes to allergen-induced bronchial hyperresponsiveness but not to bronchial eosinophilia, indicating that these are independently expressed.     

Brain inducible nitric oxide synthase is involved in interleukin-1beta-induced activation of the central sympathetic outflow in rats

Nitric oxide (NO) has been recognized as a neurotransmitter or a neuromodulator in the central nervous system. Brain NO is mainly generated either by neuronal NO synthase (NOS) or by inducible NOS. Previously we reported that central NO is involved in the elevation of plasma noradrenaline levels induced by intracerebroventricularly (i.c.v.) administered interleukin-1beta in rats [Eur. J. Phamacol. 317 (1996) 61]. In the present study, therefore, we tried to characterize which type of NOS isoforms is involved in the cytokine-induced responses using selective inhibitors of each NOS isoform in urethane-anesthetized rats. I.c.v. administered interleukin-1beta (100 ng/animal) elevated plasma levels of noradrenaline but not adrenaline. The cytokine-induced elevation of plasma noradrenaline levels was attenuated by cycloheximide, an inhibitor of protein synthesis, in a dose-dependent manner (10 and 20 microg/animal, i.c.v.). S-ethylisothiourea (0.1 and 0.5 microg/animal, i.c.v.), an inhibitor of inducible NOS, dose-dependently reduced the cytokine-induced elevation of plasma noradrenaline levels, while 7-nitroindazole (5 and 10 microg/animal, i.c.v.), an inhibitor of neuronal NOS, had no effect. These results suggest the involvement of brain inducible NOS in the interleukin-1beta-induced activation of the central sympathetic outflow in rats.     

大鼠脑出血周边组织NO含量和NOS活性变化及对细胞凋亡的影响

目的：研究大鼠脑出血周边组织一氧化氮(NO)含量和一氧化氮合酶(NOS)活性变化及与细胞凋亡的关系。方法：①Wistar大鼠104只,随机分为对照组、脑出血组、脑出血 氮硝基左旋精氨酸(NNLA)组,后两组各分为(4h、6h、12h、1d、3d、7d)6个时间点。②测定出血周边组织NO含量、NOS活性及神经细胞凋亡。结果：①大鼠脑出血周边组织NO、诱导型一氧化氮合酶(iNOS),4h开始升高,3di NOS、NO达峰值。②大鼠脑出血周边组织6h出现凋亡,细胞3d凋亡细胞达峰值,与iNOS峰值对应,7d时仍存在较多凋亡细胞。③NNLA干预后NO含量、iNOS活性及凋亡细胞数量与脑出血组对应时间点比较显著下降,差异显著。结论：大鼠脑出血周边组织神经细胞存在长时间凋亡,NO、iNOS可以促进其凋亡,NOS抑制剂减少大鼠脑出血周边组织神经细胞凋亡。     

The effects of amphotericin B on angiogenesis in chick chorioallantoic membrane

Objective: Amphotericin B (AmB) is widely used as a mainstay in the treatment of sight-threatening fungal endophthalmitis. From the time that itraconazole was discovered to have a previously unknown anti-angiogenic activity, we have suspected that AmB may have possible effects on ocular angiogenesis. The purpose of this study was to evaluate the in vivo anti-angiogenic effect of AmB in the chick chorioallantoic membrane (CAM) model.

Materials and methods: Atak-S type fertilized eggs obtained from the Poultry Institution were used. The eggs were kept under 37?°C at 85–90% relative humidity throughout the experiment. Amphotericin B was prepared in two different concentrations (AmB 125?μg/1?mL and 0.125?μg/1?mL). The CAMs treated with sterile distilled water was specified as controls. About 0.1?mL of each containing 12.5 and 0.0125?µg of AmB, respectively, were dropped to CAM surface. Thirteen eggs were used for each group. The results were evaluated at the 48th hour of the administration of the drugs and recorded by digital camera.

Results: A reduction of angiogenesis in CAM area which treated with 125?μg/1?mL of AmB was appreciable macroscopically. The affected areas showed impaired radial arrangement of small vessels with the presence of avascular zone at periphery. The dose of 0.125?μg/1?mL AmB did not show any visible anti-angiogenic effect. Numerous blood vessels with a radially arranged pattern developed toward the periphery after 48?h of treatment. In the CAMs that treated with distilled water, physiological angiogenesis was observed in allantoic vessels. Vessel formation seems to be similar in CAMs treated with 0.125?μg/1?mL AmB with the presence of visibly non-malformed alive embryos.

Conclusions: The present study gives the impression that AmB has the capacity to serve as an anti-angiogenic treatment. As it is a preliminary CAM study only, further studies on both animals and humans are required.     

冠心病患者血一氧化氮/一氧化氮酶和内皮素检测的临床意义

目的　探讨了 NO/ NOS和 ET在冠心病患者中的变化。方法　分别应用生化法和放免法检测了3 9例冠心病患者血 NO/ NOS和 ET含量 ,并与 3 5名正常健康人作对照。结果　冠心病患者血 NO水平低于正常人 ( P<0 .0 5 ) ,NOS和 ET水平高于正常人 ( P<0 .0 1)。结论　 NO/ NOS和 ET水平的变化与冠心病的发生与发展密切相关     

Cigarette smoke-inhibition of neurogenic bronchoconstriction in guinea-pigs in vivo: involvement of exogenous and endogenous nitric oxide

1. We investigated the effect of acute inhalation of cigarette smoke on subsequent non-adrenergic, non-cholinergic (NANC) neural bronchoconstriction in anaesthetized guinea-pigs in vivo by use of pulmonary insufflation pressure (PIP) as an index of airway tone. The contribution of endogenous nitric oxide (NO) was investigated with the NO synthase inhibitor N^G-nitro-L-arginine methyl ester (L-NAME). The contribution of plasma exudation to the response was investigated with Evans blue dye as a plasma marker.
2. Inhalation of 50 tidal volumes of cigarette smoke or air had no significant effect on baseline PIP. In the presence of propranolol and atropine (1 mg kg⁻¹ each), electrical stimulation of the vagus nerves in animals given air 30 min previously induced a frequency-dependent increase in PIP above sham stimulated controls (16 fold increase at 2.5 Hz, 24 fold increase at 10 Hz). In contrast, in smoke-exposed animals, the increase in subsequent vagally-induced PIP was markedly less than in the air controls (90% less at 2.5 Hz, 76% less at 10 Hz).
3. L-NAME (10 mg kg⁻¹), given 10 min before air or smoke, potentiated subsequent vagally-induced (2.5 Hz) NANC bronchoconstriction by 338% in smoke-exposed animals, but had no significant effect in air-exposed animals. The inactive enantiomer D-NAME (10 mg kg⁻¹) had no effect, and the potentiation by L-NAME was partially reversed by the NO-precursor L-arginine (100 mg kg⁻¹). Vagal stimulation did not affect the magnitude of vagally-induced bronchoconstriction 30 min later.
4. Cigarette smoke exposure reduced the magnitude of subsequent bronchoconstriction induced by neurokinin A (NKA) by 37% compared with the effect of NKA in air-exposed animals. L-NAME had no significant effect on the smoke-induced inhibition of NKA-induced bronchoconstriction.
5. Vagally-induced plasma exudation in the main bronchi was greater in smoke-exposed animals compared with air-exposed animals (120% greater at 2.5 Hz, 82% greater at 10 Hz).
6. We conclude that cigarette smoke-induced inhibition of subsequent NANC neurogenic bronchoconstriction is not associated with inhibition of airway plasma exudation and is mediated in part via exogenous smoke-derived NO, or another bronchoprotective molecule, and by endogenous NO.

     

Nitric oxide scavenger carboxy-PTIO potentiates the inhibition of dopamine uptake by nitric oxide donors

2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (carboxy-PTIO) has been increasingly used as nitric oxide (NO) scavenger. Carboxy-PTIO reacts with NO to form nitric dioxide and 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl (carboxy-PTI). In rat C6 glioma cells expressing human dopamine transporter, carboxy-PTIO paradoxically potentiated the inhibition of [(3)H]dopamine uptake by two NO donors, diethylamine/NO and (Z)-1-[N-(3-ammoniopropyl)-N-(n-propyl)-amino]/NO. Further examinations revealed that carboxy-PTI concentration-dependently reduced dopamine uptake, indicating that the formation of carboxy-PTI may account for the failure of carboxy-PTIO to abolish NO elicited effects. These results suggest that caution should be taken in interpreting data obtained using carboxy-PTIO and probably other NO scavengers.     

The inhibition of inducible nitric oxide synthase and oxidative stress by agmatine attenuates vascular dysfunction in rat acute endotoxemic model

Vascular dysfunction leading to hypotension is a major complication in patients with septic shock. Inducible nitric oxide synthase (iNOS) together with oxidative stress play an important role in development of vascular dysfunction in sepsis. Searching for an endogenous, safe and yet effective remedy was the chief goal for this study. The current study investigated the effect of agmatine (AGM), an endogenous metabolite of l-arginine, on sepsis-induced vascular dysfunction induced by lipopolysaccharides (LPS) in rats. AGM pretreatment (10 mg/kg, i.v.) 1 h before LPS (5 mg/kg, i.v.) prevented the LPS-induced mortality and elevations in serum creatine kinase-MB isoenzyme (CK-MB) activity, lactate dehydrogenase (LDH) activity, C-reactive protein (CRP) level and total nitrite/nitrate (NOx) level after 24 h from LPS injection. The elevation in aortic lipid peroxidation illustrated by increased malondialdehyde (MDA) content and the decrease in aortic glutathione (GSH) and superoxide dismutase (SOD) were also ameliorated by AGM. Additionally, AGM prevented LPS-induced elevation in mRNA expression of iNOS, while endothelial NOS (eNOS) mRNA was not affected. Furthermore AGM prevented the impaired aortic contraction to KCl and phenylephrine (PE) and endothelium-dependent relaxation to acetylcholine (ACh) without affecting endothelium-independent relaxation to sodium nitroprusside (SNP). In conclusion: AGM may represent a potential endogenous therapeutic candidate for sepsis-induced vascular dysfunction through its inhibiting effect on iNOS expression and oxidative stress.     

荆花胃康胶丸对溃疡大鼠胃黏膜NO,NOS和ET含量的影响

目的:观察荆花胃康胶丸对溃疡大鼠胃黏膜内皮素(ET)、一氧化氮(NO)、一氧化氮合酶(NOS)含量的影响。方法:采用Okabe氏法造成大鼠胃溃疡模型,随机将模型动物分为蒸馏水对照组、荆花胃康胶丸30,20, 10 mg·kg~(-1)·d~(-1)组、硫糖铝10 mg·kg~(-1)·d~(-1)及法莫替丁5 mg·kg~(-1)·d~(-1)组,每组8只。各组均灌胃给药,qd,连续10 d。末次给药后次日,测定各组溃疡面积,并测定溃疡周围组织NO,NOS及ET含量。结果:与对照组相比,荆花胃康胶丸30,20,10 mg·kg~(-1)·d~(-1)组的溃疡面积显著降低,溃疡周围组织NO及NOS的含量明显增高,ET的含量明显降低(P＜0．01),且呈现剂量依赖性;荆花胃康胶丸30 mg·kg~(-1)·d~(-1)组的保护作用优于硫糖铝及法莫替丁组(P＜0．05)。结论:荆花胃康胶丸可能通过增加胃溃疡组织NO及NOS的含量及降低ET的含量来发挥胃黏膜修复作用。     

Associative learning is enhanced by selective neuronal nitric oxide synthase inhibitors and retarded by a nitric oxide donor in the rabbit

RATIONALE: Previous studies had reported that the nitric oxide (NO) donor, sodium nitroprusside (SNP), retarded and the non-specific NO synthase (NOS) inhibitor, Nomega-nitro-L-arginine methyl ester (L-NAME), enhanced acquisition of classically conditioned responses (CRs). These effects of IV SNP and IP L-NAME on CR acquisition occurred in the absence of any effect on non-associative processes or performance variables and at a time when there were no alterations in blood pressure or heart rate. OBJECTIVES: In this study, we examined whether the changes in associative learning produced by L-NAME and SNP were due to their central effects on NO content of brain. To this end, we examined the effects of the selective neuronal NOS inhibitors 7-nitroindazole (7-NI) and AR-R 17477 and the effects of central (ICV) administration of the NO donor SNP on learning. METHODS: Effects of drugs on CR acquisition were determined during classical conditioning of the rabbit's nictitating membrane (NM) response. Explicitly unpaired presentations of conditioned stimuli (CSs) and unconditioned stimuli (USs) were employed to measure non-associative levels of responding and unconditioned response (UR) topography. RESULTS: The SC injection of 7-NI and AR-R 17477 significantly enhanced associative learning while ICV administration of SNP significantly retarded learning. CONCLUSION: Production of NO within the brain by neuronal NOS normally acts to retard associative learning presumably by decreasing excitability within neuronal circuits involved in the acquisition of the classically conditioned NM reflex.     

一氧化氮合酶抑制剂的研究进展

一氧化氮（ｎｉｔｒｉｃｏｘｉｄｅ,ＮＯ）是一种能调节细胞多种功能的信息分子,它参与心血管、外周和中枢神经以及免疫等系统生理过程和生物信号的调节。体内组织中的ＮＯ由ＮＯ合酶（Ｎｉｔｒｉｃｏｘｉｄｅｓｙｎｔｈａｓｅ,ＮＯＳ）催化左旋精氨酸而合成,合成后的ＮＯ迅速跨膜扩散释放。各种调节ＮＯ释放的因素均作用于ＮＯＳ催化的化学反应过程,而体内影响该反应的ＮＯＳ在各组织的表达不同。特异性ＮＯＳ抑制剂通过调控ＮＯ的合成,对ＮＯＳ表达相关的各种疾病的预防和治疗具有重要的临床意义。本文对近年来ＮＯＳ抑制剂的研究进展作一概述。     

Enhancement of the anti-inflammatory and anti-arthritic effects of theophylline by a low dose of a nitric oxide donor or non-specific nitric oxide synthase inhibitor

Background and purpose:

Although there are many new specific phosphodiesterase inhibitors with anti-inflammatory activity, none have yet reached the market because of their low therapeutic efficacy. Our study was aimed to evaluate the anti-inflammatory and anti-arthritic effect of an established phosphodiesterase inhibitor, theophylline, and to investigate the effect of the nitric oxide (NO) donor, sodium nitroprusside (SNP) or NO synthase inhibitor, L-N^G-monomethyl arginine (L-NMMA) on its actions.

Experimental approach:

The effects of theophylline alone and combined with SNP or L-NMMA on the pathogenesis of adjuvant-induced arthritis in rats were evaluated.

Key results:

Prophylactic or therapeutic doses of theophylline significantly ameliorated the pathogenesis of adjuvant arthritis in rats as evidenced by a significant decrease in the arthritis index, hind paws volume, ankle joint diameter, fever, body weight loss and hyperalgesia in a dose-dependent manner. Inflammatory cellular infiltrate in synovium of ankle joint and pannus formation were also markedly inhibited. Interleukin-10 (IL-10) levels were significantly increased in arthritic rats given theophylline alone or in combination with either SNP or L-NMMA. Co-administration of a low dose of SNP or L-NMMA enhanced significantly the anti-inflammatory and anti-arthritic effect of theophylline. In contrast, a high dose of SNP counteracted the anti-inflammatory and anti-arthritic effects of theophylline.

Conclusions and Implication:

These findings confirm the anti-inflammatory and anti-arthritic activities of theophylline and suggest a new approach to enhance the anti-inflammatory and anti-arthritic effects of theophylline would be to administer it in combination with a low dose of a NO donor or a non-specific NO synthase inhibitor.     

戊四唑癫痫大鼠脑组织一氧化氮含量和一氧化氮合酶活性变化

探讨一氧化氮在戊四唑癫病发机制中的作用。方法每天注射戊四唑建立在鼠癫痫模型,测定癫病发作后大鼠大脑皮质,海马一氧化氮和一氧化氮合酶活性变化,结果癫痫发作后海马ＮＯ含量和ＮＯＳ活性显著升高,结 戊四唑诱导的癫痫中具有致痫性。