一氧化氮与免疫调节

一氧化氮(Nitric Oxide,NO)目前被认为是具有高度活性的分子,近年来研究表明:内源性NO在免疫、呼吸、循环等系统中作为一种信息分子发挥重要作用。被认为是不同其它物质的神经递质。NO参与许多生理和病理过程,特别是巨噬细胞毒及免疫调节,松弛血管平滑肌,抑制血小板聚集等作用。     

一氧化氮与病理性瘢痕的研究进展

一氧化氮 (nitricoxide,NO)广泛存在于脊椎动物的各种细胞中 ,是一种作用短暂的无机小分子 ,内源性NO作为一种信息分子参与许多生理和病理过程并在其中发挥重要作用。病理性瘢痕 (pathologicalscar)包括增生性瘢痕和瘢痕疙瘩 ,在病理改变上 ,这些瘢痕以真皮纤维化和间质胶原蛋白过度积聚为特征 ,并伴有炎性细胞浸润及真皮微血管异常。皮肤正常创伤愈合时 ,真皮内纤维组织形成能够及时起动 ,又可适时终止 ,而在病理性瘢痕中 ,这种正常生理过程的调节可能发生了改变 ,皮肤创伤愈合的调节机制存在着异常。近年来的研究表明 ,NO参与这种调节…     

一氧化氮--一氧化氮合酶系统与骨折愈合

一氧化氮（nitric oxide,NO）是在一氧化氮合酶（nitric oxide sythase,NOS）作用下氧化产生的一种小分子自由基气体.由于其分子量小,脂溶性及化学性质活泼,因而极易透过生物膜,是细胞间、细胞内的重要信使分子.由于其合成易于调节,作为高级生物体,调节的有效信号在循环、呼吸、消化及内分泌代谢等系统中发挥着重要作用.近几年来的研究发现,NO-NOS系统对骨折愈合起重要作用.本文就NO-NOS系统对骨折愈合的影响作一综述.     

一氧化氮与男性不育症

一氧化氮(nitric oxide,NO)是一种分子小,结构简单的无色、微溶于水的气体。近年来,大量的研究发现,NO具有广泛的生物学功能,它是一种新型的细胞信使分子,在调节心血管系统、神经系统和免疫功能等方面均起着重要的作用,参与多种疾病的生理过程[1]。现重点就一氧化氮与男性不育症方面的研究进展做一简要概述。     

一氧化氮对精子功能的影响

一氧化氮 (NO)是一种具有广泛生物学活性的信使分子和细胞毒性因子。近年研究表明 ,NO对哺乳动物的生殖活动具有重要的调节作用。NO参与精子发生、获能并影响精子质量。低浓度NO具有保护精子活力 ,促进精子获能的作用 ;而高浓度NO则损害生精功能 ,抑制精子活动度及降低顶体反应率。NO与氧自由基相互作用 ,共同参与精子功能的调节。     

一氧化氮对脊髓背角疼痛的调制作用

NO对脊髓背角疼痛调节的机制.一氧化氮（NO）作为信息传递物质,在周围及中枢伤害性感受传递中发挥着重要作用.研究表明,伤害性刺激引起脊髓背角神经元释放NO;NO在脊髓水平主要参与痛觉过敏的形成和发展,在一些伤害性刺激条件下,NO可作为第二信使诱导c-fos表达.NO是一种广泛存在的信息传递分子,是细胞内重要的第二信使.其作用的具体过程是：神经元突触前膜去极化使谷氨酸（Glu）等释放到突触间隙与N-甲基-D-天冬氨酸（NMDA）等受体结合,受体通道开放,Ca2＋内流与钙调蛋白（CaM）偶联,在还原型辅酶Ⅱ（NADPH）的协助下激活一氧化氮合酶（NOS）,催化L-精氨酸（LArg）,生成NO,激活可溶性鸟苷酸环化酶（sGC）,促进环鸟苷酸（cGMP）合成,作用于cGMP门控离子通道,cGMP调节的磷酸二酯酶（PDE）,cGMP依赖性蛋白激酶（PKG）等效应靶分子,参与中枢神经系统（CNS）伤害性刺激信息传递,神经元兴奋性维持等生理过程.     

精液中NO浓度对男性生育的影响

正近年来,研究发现体内一氧化氮(NO)主要由NO合成酶(nitric oxide synthase,NOS)合成。NO作为生物体内一种重要的信息分子和效应分子~([1]),具有自由基的化学性质和多种生物功能,能调节细胞信息的传递、防御、损害以及哺乳动物的生殖过程~([2-4])。然而,精液中异常的NO浓度对男性生育的影响机制未见诸报道。本课题深入研究了精     

一氧化氮对女性下尿路作用研究进展

一氧化氮(nitric oxide,NO)作为一种神经递质和信号传导分子,通过与其他神经递质及激素的相互作用,调节膀胱和尿道舒张,在女性下尿路发挥重要生理功能。NO及一氧化氮合酶(nitric oxide syn-thase,NOS)的改变和疾病的发生发展密切相关。     

一氧化氮对女性下尿路作用研究进展

一氧化氮（nitric oxide,NO）作为一种神经递质和信号传导分子，通过与其他神经递质及激素的相互作用，调节膀胱和尿道舒张，在女性下尿路发挥重要生理功能。NO及一氧化氮合酶（nitric oxide synthase,NOS）的改变和疾病的发生发展密切相关。     

NO及其调控物NOS在骨折愈合中的作用

一氧化氮(nitric oxide，NO)极易透过生物膜，是细胞间、细胞内的信使分子，其扩散速度快、穿透细胞膜的能力强、本身不稳定。由于其合成易于调节，作为高级生物体调节第二信使和神经递质，可有效地调节细胞与细胞间信息传递，在循环、呼吸、消化及内分泌代谢等系统中发挥着重要作用。目前的研究证实，NO与骨组织细胞功能关系密切。     

Nitric oxide. Novel biology with clinical relevance.

OBJECTIVE: The author provides the reader with a view of the regulation and function of nitric oxide (NO), based on the three distinct enzyme isoforms that synthesize NO. SUMMARY BACKGROUND DATA: Nitric oxide is a short-lived molecule exhibiting functions as diverse as neurotransmission and microbial killing. Recent advances in the characterization of the enzymes responsible for NO synthesis and in the understanding of how NO interacts with targets have led to new insights into the many facets of this diverse molecule. METHODS: Nitric oxide is produced by one of three enzyme isoforms of NO synthesis. These enzymes vary considerably in their distribution, regulation, and function. Accordingly, the NO synthesis or lack of NO production will have consequences unique to that isoform. Therefore, this review summarizes the regulation and function of NO generated by each of the three isoforms. RESULTS: Nitric oxide exhibits many unique characteristics that allow this molecule to perform so many functions. The amount, duration, and location of the NO synthesis will depend on the isoform of NO synthase expressed. For each isoform, there probably are disease processes in which deficiency states exist. For induced NO synthesis, states of overexpression exist. CONCLUSIONS: Understanding the regulation and function of the enzymes that produce NO and the unique characteristics of each enzyme isoform is likely to lead to therapeutic approaches to prevent or treat a number of diseases.     

Interactions between morphine and nitric oxide in various organs

Nitric oxide (NO) plays obligatory roles as an important intercellular messenger in the control of physiological functions and it also participates in pathophysiological interventions. This labile, gaseous molecule is also involved in mechanisms underlying the beneficial and untoward actions of therapeutic agents. Endogenous NO is formed by endothelial and neurogenic NO synthases that are constitutively present mainly in the endothelium and nervous system, respectively, and is induced by lipopolysaccharides or cytokines mainly in mitochondria, glial cells, and vascular smooth muscle cells. NO modulates the effects of morphine on processes involving the central nervous system, such as learning, memory, convulsion, thermoregulation, and penile erection. This molecule is also involved in the modification of morphine actions on the cardiovascular, digestive, and respiratory systems. Morphine regulates NO bioavailability in various organs. NO formed by inducible NO synthase participates in some morphine actions in the immune system. Information concerning interactions between NO and morphine and other opioids in a variety of organs and tissues is quite useful in establishing new strategies for minimizing the noxious and unintended reactions that are frequently encountered during analgesic therapy.     

The yin and yang of nitric oxide: reflections on the physiology and pathophysiology of NO

Nitric oxide (NO.) is an arginine-derived nitrogen-based radical that is rapidly becoming one of the most important molecular species to be discovered. Over the past decade, an explosion of evidence has revealed the extreme complexity of function of this seemingly simple inorganic molecule. It is now evident that NO. demonstrates a functional dualism, playing a pivotal role in numerous physiologic and pathophysiologic processes. Whether this molecule is beneficial or detrimental is dependent upon the tissue of generation, the level of production, the oxidative/reductive (redox) environment in which this radical is generated, and the presence or absence of NO. transduction elements. Nitric oxide is generated by three independent isoenzymes that resemble the p-450 enzyme superfamily in both form and function. It ultimately alters enzymatic function through covalent modification, redox interactions, and interactions with metallic functional centers. This radical is a key figure in a number of pathophysiologic processes by means of similar yet uncoordinated interactions. In consideration of the already broad spectrum of roles attributed to NO., it seems highly likely that this molecule will be implicated in an ever widening variety of functions relative to the practice of otolaryngology-head and neck surgery. This article reviews the enzymology, signal transduction mechanisms, physiology, and pathophysiology of NO. as it pertains to head and neck cancer.     

The cardiovascular significance of nitric oxide

Nitric oxide (NO) synthesized from L-arginine is a ubiquitous intercellular chemical messenger involved in signal transduction in diverse mammalian cells. The isolation of molecular clones for NO synthases has permitted the characterization of several distinct enzyme isoforms. NO synthesized in vascular endothelial cells plays an important role in the control of vascular tonus and platelet aggregation, through the activation of guanylate-cyclase activity in target tissues mediated by NO. Nitric oxide which is produced by cytokine activated mononuclear cells plays an important role in inflammation and immunity as a cytotoxic effector molecule and as a transducer molecule in immune cells and in oxidative stress as a potential source of intracellular free radicals. An increase in reactive oxygen species can produce damage to lipids, proteins and DNA and induce necrosis or apoptosis. The implication of NO in different pathological processes, such as atherosclerosis, diabetes, ischaemia and reperfusion, or during inflammatory processes and the generation of free radicals contributing to the endothelial injury associated to these processes.     

Nitric Oxide and the Lung: An Overview

Abstract: This brief discussion focuses on the effects of nitric oxide (NO) in the lung. A short introduction of some of the physical characteristics of the NO gas molecule and the endogenous production of NO by the vascular endothelium is addressed first. This is followed by a review of inhaled NO use as a hronchodilator of the airway and recent findings of the endogenous production of NO during positive end-expiratory pressure and the possible role of NO produced in the paranasal Sinuses. Next, the use of inhaled NO for both pulmonary hypertension and improvement in oxygenation under a variety of clinical situations is discussed. Finally, some suggestions are given regarding the safe delivery of inhaled NO during clinical applications using a facemask, an anesthesia circuit, and a mechanical ventilator.     

Nitric oxide: actions and roles in arthritis and diabetes

Nitric oxide (NO) plays physiological and pathophysiological roles as vasodilator, neurotransmitter, anti-microbial effector molecule, and immunomodulator. Of interest to podiatric medicine is the growing evidence implicating NO in inflammation, arthritis, diabetes, vascular complications and wound healing. Release of NO and formation of peroxynitrite in chronic inflammation have been linked to destruction of chondrocytes, endothelium and pancreatic islet cells. NO may be a potential target for pharmacologic intervention and gene therapy.     

NO对前列腺及阴茎勃起功能的调节作用

一氧化氮是一种不稳定的低分子有害气体 ,同时它又是一种生物活性物质 ,参与了多种疾病的病理生理过程。一氧化氮在体内由L 精氨酸在一氧化氮合成酶的作用下生成 ,作为一种非肾上腺能非胆碱能神经递质 ,对动物和人的生殖泌尿器官平滑肌张力起着重要的调节作用。本文简要介绍一氧化氮在体内的产生机制和分布 ,并着重概述一氧化氮对平滑肌舒张调节作用机理 ,及其在非手术治疗前列腺增生导致下尿路梗阻及改善阴茎勃起功能障碍方面的临床应用。     

Nitric Oxide Mechanism of Protection in Ischemia and Reperfusion Injury

In 1992 nitric oxide (NO) was declared molecule of the year by Science magazine, and ever since research on this molecule continues to increase. Following this award, NO was shown to be a mediator/protector of ischemia and reperfusion injury in many organs, such as the heart, liver, lungs, and kidneys. Controversy has existed concerning the actual protective effects of NO. However, literature from the past 15 years seems to reinforce the consensus that NO is indeed protective. Some of the protective actions of NO in ischemia and reperfusion are due to its potential as an antioxidant and anti-inflammatory agent, along with its beneficial effects on cell signaling and inhibition of nuclear proteins, such as NF-κ B and AP-1. New therapeutic potentials for this drug are also continuously emerging. Exogenous NO and endogenous NO may both play protective roles during ischemia and reperfusion injury. Sodium nitroprusside and nitroglycerin have been used clinically with much success; though only recently have they been tested and proven effective in attenuating some of the injuries associated with ischemia and reperfusion. NO inhalation has, in the past, mostly been used for its pulmonary effects, but has also recently been shown to be protective in other organs. The potential of NO in the treatment of ischemic disease is only just being realized. Elucidation of the mechanism by which NO exerts its protective effects needs further investigation. Therefore, this paper will focus on the mechanistic actions of NO in ischemia and reperfusion injury, along with the compound's potential therapeutic benefits.     

Folic acid may be a potential addition to diabetic foot ulcer treatment - a hypothesis

Delayed wound healing in diabetes is a challenging medical and societal problem for which there is currently no efficacious treatment. One of the major contributors of this problem is nitric oxide (NO) deficiency. NO is a critical signalling molecule essential for normal wound repair. Sustained hyperglycaemia in diabetes leads to increased vascular superoxide production, which inactivates NO and causes vascular dysfunction. New therapeutic regiments and strategies to enhance endothelial NO production are a new hope to improve impaired diabetic wound healing. One of the agents that have the ability to improve endothelial NO generation in diabetic patients is folic acid. Folic acid ability to conserve NO bioactivity may be due to homocysteine-lowering effects of folates, antioxidant actions and effects on cofactor availability. Considering these data, we hypothesised that folic acid supplementation may ameliorate delayed diabetic wound healing by increasing NO bioavailability. The potential of exogenous folic acid as an inexpensive and safe oral therapy stimulates ongoing investigations.     

一氧化氮的肿瘤生物学效应

一氧化氮是人体内活跃的具有多种生物学活性的小分子物质,目前研究表明其在多种肿瘤组织内表达。从肿瘤生物学角度来看,一氧化氮可以体现出许多不同的、有时看来甚至是相互矛盾的生物学效应。这些不同的生物学效应与很多因素有关,其中最重要的是组织中一氧化氮的浓度。高浓度的一氧化氮可以介导肿瘤细胞的凋亡和抑制肿瘤生长;相对低浓度的一氧化氮可促使肿瘤生长和肿瘤细胞增殖,并可以使肿瘤细胞增强对放疗和某些化疗药物的耐受性。一氧化氮对肿瘤生长的双向调节作用为肿瘤的研究提供了一个新的方向。