丙泊酚对N-甲基-D-天冬氨酸所致PC12细胞损伤的保护作用

目的　探讨静脉麻醉药丙泊酚 (PPF)脑保护作用的可能机制。方法　乳酸脱氢酶 (LDH)法及MTT比色法判断细胞损伤程度及细胞存活率 ,Fura 2 /AM荧光标记法测定细胞内Ca2 + 浓度 ( [Ca2 + ]i)的变化 ,分光光度法测定细胞一氧化氮合酶 (NOS)活性。结果　N 甲基 D 天冬氨酸 (NMDA) 3 0 0 μmol·L-1处理4h可明显导致PC1 2细胞的损伤 ,表现为LDH释放量明显增加 ,吸光度值A570nm明显降低 ,细胞存活率降低 ,同时 [Ca2 + ]i 和NOS活性则明显增加。PPF6.2 5 ,2 5 ,1 0 0 ,40 0 μmol·L-1与NMDA同时处理PC1 2细胞则使LDH释放量显著降低 ,细胞存活率增加。PPF 1 2 .5和 1 2 5 μmol·L-1可显著降低NMDA诱导的[Ca2 + ]i 水平及NOS活性的提高。结论　PPF对NMDA所致的PC1 2细胞损伤有明显的保护作用 ,其机制可能与其抑制NMDA受体的功能 ,降低 [Ca2 + ]i,减弱Ca2 + 超载 ,并降低NMDA诱导的NOS活性增加有关。提示PPF可能是通过抑制NMDA受体 Ca2 + NOS通路的功能而产生细胞保护效应     

Evidence that inhibition of spinal nitric oxide production contributes to the antinociceptive effects of emulsified isoflurane on formalin-induced pain in rats

The aim of the present study was to investigate the contribution of spinal nitric oxide (NO) to the antinociceptive effects of emulsified isofluane in rats. The formalin test was used to assess nociceptive responses. Immunocytochemistry and histochemistry were performed to determine the effects of emulsified isoflurane on formalin-induced changes in Fos-like immunoreactive (Fos-LI)- and nicotinamide adenine dinucleotide phosphatediaphorase (NADPH-d)-positive neurons, respectively. The results showed that emulsified isofluane, administered intraperitoneally, significantly decreased the formalin-induced paw licking time and that this was attenuated by pretreatment with intrathecal injection of the NO precursor L-arginine. Furthermore, Fos-LI- and NADPH-d-positive neurons were mainly found in the ipsilateral dorsal horn after injection of formalin, some of which were Fos-LI/NADPH-d double-labelled neurons. Administration of emulsified isofluane significantly decreased Fos-LI- and NADPH-d-positive, as well as Fos-LI/NADPH-d double-labelled, neurons. Finally, emulsified isofluane produced a significant reduction of NOS activity and a decrease of NO production in the spinal cord of formalin-treated rats. In conclusion, the results suggest that inhibition of spinal NO production contributes to the antinociceptive effects of emulsified isofluane on formalin-induced pain in rats.     

吗啡耐受及内脏痛敏的相关机理

目的　吗啡耐受是一种潜在的痛觉过敏 ,慢性内脏炎痛刺激后也产生内脏痛敏。因此探讨慢性内脏炎痛刺激及吗啡耐受间共同的细胞机理及N 甲基 D 天冬氨酸 (NMDA)受体相关的调节机理 ,为合理用药及药物开发提供实验依据。方法　利用急慢性内脏痛炎痛模型 ,直肠扩张痛阈测定及生物化学检测的方法进行机理研究。结果　结肠炎症和慢性吗啡耐受的大鼠均出现直肠扩张痛阈降低 ,即内脏痛敏现象 ,而慢性地佐环平 (MK 80 1)和L NG 硝基精氨酸甲酯 (L NAME)处理吗啡组的平均痛阈末见明显改变。内脏炎痛和耐受组大鼠脊髓及海马部位一氧化氮合酶 (NOS)上调 ,而MK 80 1和L NAME预处理组含量无明显变化。慢性内脏炎痛及吗啡耐受组背角神经元 [Ca2 + ]i 显著增高 ,而MK 80 1预处理的炎痛及耐受组则无明显改变。结论　吗啡耐受和痛觉敏感化在机理上存在某些共同之处 ,均在NMDA受体的激活、一氧化氮生成及细胞内钙上发生可塑性变化。     

Aberrant regulation and function of Src family tyrosine kinases: their potential contributions to glutamate-induced neurotoxicity

Excitotoxicity, a major cause of neuronal death in acute and chronic neurodegenerative diseases and conditions such as stroke and Parkinson's disease, is initiated by overstimulation of glutamate receptors, leading to calcium overload in affected neurons. The sustained high concentration of intracellular calcium constitutively activates a host of enzymes, notably the calcium-activated proteases calpains, neuronal nitric oxide synthase (nNOS) and NADPH oxidase (NOX), to antagonise the cell survival signalling pathways and induce cell death. Upon overactivation by calcium, calpains catalyse limited proteolysis of specific cellular proteins to modulate their functions; nNOS produces excessive amounts of nitric oxide (NO), which, in turn, covalently modifies specific enzymes by S-nitrosylation; and NOX produces excessive amounts of reactive oxygen species (ROS) to inflict damage to key metabolic enzymes. Presumably, key regulatory enzymes governing cell survival and cell death are aberrantly modified and regulated by calpains, NO and ROS in affected neurons; these aberrantly modified enzymes then cooperate to induce the death of affected neurons. c-Src, an Src family kinase (SFK) member, is one of the aberrantly regulated enzymes involved in excitotoxic neuronal death. Herein we review how SFKs are functionally linked to the glutamate receptors and the biochemical and structural basis of the aberrant regulation of SFKs. Results in the literature suggest that SFKs are aberrantly activated by calpain-mediated truncation and S-nitrosylation. Thus, the aberrantly activated SFKs are targets for therapeutic intervention to reduce the extent of brain damage caused by stroke.     

芍药甙对大鼠皮层神经细胞钙超载损伤的保护作用

采用组织培养法 ,以原代大鼠大脑皮层神经细胞为材料 ,制备咖啡因 ,氯化钾及N 甲基 D 门冬氨酸 (NMDA)诱导的钙超载损伤模型 .探讨芍药甙对大鼠神经细胞钙超载损伤模型的保护作用及其机理 .实验发现加入芍药甙保护 2 4h ,对上述 3种细胞内钙超载所致神经细胞损伤具有显著的保护作用 ,活细胞结晶紫染色和上清液中乳酸脱氢酶检测提示 10 4 .1～ 4 16 .3μmol·L- 1芍药甙对咖啡因型钙超载损伤显著保护 ,6 .5～ 4 16 .3μmol·L- 1对氯化钾型钙超载损伤有显著保护 ,4 16 .3μmol·L- 1对NMDA型钙超载损伤有显著保护 .随着浓度的增加 ,芍药甙保护作用更加明显 .芍药甙对不同类型胞内钙超载损伤的保护作用的强度依次为氯化钾 ,咖啡因型和NMDA .形态学检查也证实芍药甙可显著提高 3种钙超载损伤模型中的大鼠神经细胞的存活数 .     

红霉素对人脐静脉内皮细胞一氧化氮及钙离子水平的影响

目的　探讨红霉素对人脐静脉内皮细胞一氧化氮通路及钙离子的影响。方法　应用一氧化氮及一氧化氮合酶试剂盒测定内皮细胞NO的含量及NOS的活性 ,采用Fura 2负载荧光技术检测胞内游离钙水平。结果　红霉素能明显增加内皮细胞NO的产生和胞内游离钙水平 ,并能明显增强NOS的活性 ,具有浓度和时间效应。结论　红霉素对人脐静脉内皮细胞一氧化氮通路的影响可能通过胞内游离钙而起作用。     

A common NOS1AP genetic polymorphism is associated with increased cardiovascular mortality in users of dihydropyridine calcium channel blockers

AIMS

Omalizumab, a subcutaneously administered anti-IgE antibody, is effective for moderate-to-severe persistent allergic asthma. The aims were to (i) describe the population pharmacodynamics of free IgE with a mechanism-based, nonlinear, omalizumab–IgE binding model; (ii) deduce a target-free IgE suppression level by correlation with clinical outcomes; and (iii) check the adequacy of current approved dosing tables and explore potential doses and regimens beyond.

METHODS

Concentration data (omalizumab, free and total IgE) were obtained from 1781 patients aged 12–79 years, in four sparsely sampled randomized, placebo-controlled studies and 152 subjects in a richly sampled single-dose study. NONMEM predictive performance across the range of bodyweights (39–150 kg) and baseline IgE (19–1055 IU ml⁻¹) was checked by simulation. Predicted free IgE levels were correlated with time-averaged patient diary clinical outcomes.

RESULTS

The model accurately predicted observed omalizumab, free and total IgE concentrations. Free IgE concentrations correlated well with clinical signs and symptoms, allowing a target concentration of 14 ng ml⁻¹, at the midpoint of 4-week clinical observation periods, to be set for determining the dose and regimen for omalizumab.

CONCLUSIONS

The omalizumab–IgE binding model is predictive for free IgE and demonstrates a nonlinear time-dependent relationship between free IgE suppression and clinical outcomes in asthma. Although currently approved dosing tables are close to optimal, it should be possible to treat patients with higher levels of baseline IgE if higher doses can be administered.     

Effects of resistin on insulin signaling in endothelial cells

The objective of this study was to investigate the effects of resistin on insulin signaling in human umbilical vein endothelial cells (HUVECs). HUVECs were incubated with recombinant human resistin (0–100 ng/mL) for 24 h. Akt and endothelial nitric oxide synthase (eNOS) phosphorylation levels of endothelial cells under basal or insulin stimulated conditions were measured by Western blot. Nitric oxide (NO) production of HUVECs was also detected. The results showed that resistin could significantly inhibit Akt and eNOS phosphorylation and NO production in endothelial cells under insulin stimulated conditions (P < 0.05 vs control). But under basal conditions, treatment with resistin could result in a decrease in eNOS phosphorylation (P < 0.05 vs control) but had no effect on NO production and Akt phosphorylation levels. These findings suggested that resistin exerted an inhibitory effect on NO production by inhibiting insulin signaling and eNOS phosphorylation in endothelial cells.     

硝基精氨酸—赖氨酸三肽合成及其对一氧化氮合酶的抑制作用

液相合成法合成了由左旋精氨酸、左旋赖氨酸组成的硝基精氨酸-赖氨酸三肽HCl．Arg(NO     

(-)-S·R-蝙蝠葛苏林碱对N-甲基-D-天门冬氨酸引起大鼠皮层神经元损伤的保护作用

蝙蝠葛苏林碱（ｄａｕｒｉｓｏｌｉｎｅ，Ｄａｕ）是从防己科植物蝙蝠葛根茎中提取的生物碱，（－）－Ｓ·Ｒ－Ｄａｕ是其人工合成非对映异构体．研究表明它的药理活性比天然品强很多［１］．我们最近报道（－）－Ｓ·Ｒ－Ｄａｕ能抑制谷氨酸（Ｇｌｕ）对原代培养的大鼠皮...     

长期小剂量L-NAME的使用对正常心肌损害的研究

目的 探讨慢性小剂量一氧化氮合酶抑制剂对大鼠正常心脏的损害的作用。方法 将雄性SD大鼠分成两组,即N-硝基-L-精氨酸-甲基酯(L-NAME)组和对照组,实验组(15只)用小剂量L-NAME(12mg/kg)以灌胃法口饲, 对照组(10只)予以等体积的自来水,6周后杀死动物,观察大鼠左心室/心脏总重量和心脏重量/体重的数值变化,血清NO含量,大鼠心肌中内皮型一氧化氮合酶(eNOS)的阳性表达情况及心肌的形态学和组织学变化。结果 实验组心脏重量指数和左心室重量指数较对照组分别增加8％和8.1％,血清NO含量明显下降,心肌细胞横截面面积和平均直径较对照组分别增加83.8％和35.6％,心脏动脉壁腔比率和血管周纤维化程度较对照组分别升高;≤100μm的微动脉为20％和22.77％,100～300μm之间的小冠状动脉为19.96％和29.83％。另外,L-NAME组还可观察到心肌细胞肥大,变性和坏死,炎性细胞浸润等病理变化。结论 长期小剂量L—NAME的使用会引起的冠状动脉重修复和心肌细胞肥大、心肌纤维化。其结果与大中剂量所致结果相似。     

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。     

Selective peripheral regulation of noradrenaline and adrenaline release by nitric oxide

1. Nitric oxide (NO) has complex effects on the sympathoadrenal and cardiovascular systems and may act at both central and peripheral loci. Nitric oxide appears to act directly on blood vessels and indirectly by modulating the sympathoadrenal system. In the present study, we investigated the contribution of catecholamine release from peripheral vascular and adrenal sympathetic nerves to the cardiovascular effects of the NO synthesis inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME; 10 mg/kg). Our experiments were performed in pithed vagotomized rats to remove the influence of central and baroreflex pathways. 2. Spinal cord stimulations for 30 s periods at 1, 2, 5 and 10 Hz using pulses of 1 msec at 10 V caused marked increases in plasma adrenaline and noradrenaline. N(G)-Nitro-L-arginine methyl ester did not alter resting plasma catecholamine concentrations. However, L-NAME generally more than doubled stimulation-evoked release of adrenaline while reducing the extent of noradrenaline release relative to vehicle (saline)-treated controls. 3. N(G)-Nitro-L-arginine methyl ester significantly enhanced the vasopressor responses to spinal cord stimulation. The alpha1-adrenoceptor antagonist prazosin (0.2 mg/kg) reduced the pressor responses of electrically stimulated L-NAME-treated rats to levels below those of vehicle-treated control rats. 4. In the absence of electrical stimulation, L-NAME raised the blood pressure of pithed rats without altering plasma catecholamines and the pressor effect was briefly attenuated by L-arginine, but was unaffected by prazosin. 5. We conclude that the augmented pressor response to sympathetic stimulation in L-NAME-treated pithed rats is due largely to enhanced adrenal adrenaline release mediated by a peripheral mechanism. Stimulation of alpha(1)-adrenoceptors plays a major role in the pressor response to electrical stimulation of L-NAME-treated rats, but this is not due to L-NAME augmentation of noradrenaline release from vascular sympathetic nerves.     

Upregulation of muscarinic receptors by long-term nitric oxide inhibition in the rat ileum

1. The aim of the present study was to examine the effects of long-term nitric oxide (NO) blockade on contractions of the rat ileum induced by muscarinic agonists. 2. Male Wistar rats received the NO synthesis inhibitor NG-nitro-l-arginine methyl ester (l-NAME; 20 mg/rat per day) in drinking water for 7, 15, 30 and 60 days. Concentration-responses curves to methacholine and carbachol were obtained and pEC50 values were calculated. Saturation binding assays were performed in membranes prepared from rat ileum after 60 days of l-NAME treatment and the dissociation constant (KD) and maximal number of binding sites (Bmax) were determined by Scatchard analysis. 3. The NO synthase activity of the ileum was markedly reduced in all l-NAME-treated groups. At 60 days after l-NAME treatment, a significant increase in the potency of methacholine (fourfold) and carbachol (threefold) was observed. In binding studies, we found a significant increase in Bmax for [3H]-quinuclidinyl benzilate of approximately 57% in the l-NAME treated group without any significant change in KD values. The contractile response to methacholine was not modified by the soluble guanylate cyclase inhibitor 1H-[1,2,4]oxadiazolo-[4,3-a]quinoxalin-1-one (3 micro mol/L). No morphological alterations in the rat ileum were observed in l-NAME-treated rats. 4. Our findings suggest that treatment with l-NAME for 60 days induces a marked increase in the potency of methacholine and carbachol, as well as an increase in receptor number in the rat ileum.     

果糖二磷酸钠镁对缺血突触体游离钙浓度及一氧化氮合酶活性的影响

目的研究果糖二磷酸钠镁对缺血突触体游离钙浓度及一氧化氮合酶活性的影响,以探讨其保护脑缺血的作用机制。方法以相分离法制备正常大鼠脑突触体,氧糖剥夺培养建立缺血突触体模型,加入1.3 mmol·L^-1 SMFD,4.0 mmol·L^-1 FDP与之培养60 min后,测定突触体内游离钙浓度和一氧化氮合酶活性。结果1.3 mmol·L^-1 SMFD可明显降低缺血突触体内游离钙浓度,降低一氧化氮合酶活性,其作用强于4.0 mmol·L^-1 FDP。结论SMFD保护脑缺血的作用机制可能与其阻止脑缺血后细胞内钙超载,抑制一氧化氮合酶活性有关。     

Effects of slow, sustained, and rate-tunable nitric oxide donors on human aortic smooth muscle cells proliferation

Smooth muscle cell (SMC) proliferation has been accepted as a common event in the pathophysiology of vascular diseases, including atherogenesis and intimal hyperplasia. Delivery of the nitric oxide synthase (NOS) substrate l-arginine, pharmacological nitric oxide (NO) donors, NO gas or overexpression of NOS proteins can inhibit SMC proliferation and reduce the injury responses within the blood vessel wall. Although commercial development of NO donors that attempt to provide exogenous delivery of NO has accelerated over the last few years, none of the currently available products can provide controlled, sustained, time-tunable release of NO. Nitrosamine-based NO donors, prepared in our laboratory, present a unique and innovative alternative for possible treatments for long-term NO deficiency-related diseases, including atherosclerosis, asthma, erectile dysfunction, cancer, and neurodegenerative diseases. A family of secondary amines prepared via nucleophilic aromatic displacement reactions could be readily N-nitrosated to produce NO donors. NO release takes place in three distinct phases. During the initial phase, the release rate is extremely fast. In the second phase, the release is slower and the rate remains essentially the same during the final stage. These compounds inhibited up to 35% human aortic smooth muscle cell proliferation in a concentration-dependent manner.     

NO和iNOS在大鼠糖尿病早期肾脏中的变化

目的:观察糖尿病大鼠早期肾脏中一氧化氮(Nitric oxide,NO)含量和诱导型一氧化氮合酶(Inducible nitric oxide syn-thase,iNOS)活性变化,探讨NO/iNOS在糖尿病早期肾脏损害中的作用机制。方法:取成年健康SD大鼠60只,随机分成糖尿病组(DM组)和正常对照组(NC组),每组30只。DM组大鼠采用一次性腹腔内注射STZ制造糖尿病大鼠模型,成模后和NC组分别于第1、2、4周麻醉取左肾,用硝酸还原酶法和吸光光度法测定肾组织中NO含量、一氧化氮合酶(nitric oxide synthase,NOS)和iNOS活性。所有数据用SPSS11.5统计软件进行统计学处理。结果:①DM组大鼠肾组织中NO含量、NOS和iNOS活性分别较同批NC组有显著性差异(P<0.05);②各组大鼠中NO含量与NOS活性、iNOS活性呈正相关。结论:糖尿病大鼠早期肾脏中iNOS活性增强,催化生成的NO在糖尿病早期肾脏损害中发挥重要作用。