Division of Critical Care Medicine, Cooper University Hospital, One Cooper Plaza, 366 Dorrance, Camden, NJ 08103, USA.
Crit Care. 2009;13(4):218. doi: 10.1186/cc7706. Epub 2009 Jul 16.
Nitric oxide (NO) is a unique and nearly ubiquitous molecule that is widely utilized as a signaling molecule in cells throughout the body. NO is highly diffusible, labile, and multiply reactive, suiting it well for its role as an important regulator of a number of diverse biologic processes, including vascular tone and permeability, platelet adhesion, neurotransmission, and mitochondrial respiration. NO can protect cells against antioxidant injury, can inhibit leukocyte adhesion, and can participate in antimicrobial defense, but can also have deleterious effects, including inhibition of enzyme function, promotion of DNA damage, and activation of inflammatory processes. This molecule's chemistry dictates its biologic activity, which can be both direct and indirect. In addition, NO has bimodal effects in a number of cells, maintaining homeostasis at low doses, and participating in pathophysiology in others. Perturbation of NO regulation is involved in the most important and prevalent disease processes in critical care units, including sepsis, acute lung injury, and multiple organ failure. Given that NO is ubiquitous, highly diffusible, and promiscuously reactive, its regulation is complex. The NO concentration, kinetics, and localization, both inside and outside the cell, are clearly crucial factors. In the present update we review a selection of studies that have yielded important information on these complex but important issues. Interpretation of these and other studies aimed at elucidating physiologic and pathophysiologic roles of NO must take this complexity into account. A full review of the role of NO in these diseases is beyond the scope of the current manuscript; the present article will focus on recent advances in understanding the complex role of NO in health and disease.
一氧化氮（NO）是一种独特且广泛存在的分子，它在体内的各种细胞中作为信号分子被广泛应用。NO 具有高度的扩散性、不稳定性和多重反应性，非常适合作为许多不同生物过程的重要调节剂，包括血管张力和通透性、血小板黏附、神经传递和线粒体呼吸。NO 可以保护细胞免受抗氧化损伤，可以抑制白细胞黏附，参与抗菌防御，但也可能产生有害影响，包括抑制酶的功能、促进 DNA 损伤和激活炎症过程。这种分子的化学性质决定了它的生物活性，可以是直接的，也可以是间接的。此外，NO 在许多细胞中具有双模态效应，在低剂量下维持体内平衡，而在其他细胞中参与病理生理过程。NO 调节的紊乱与重症监护病房中最重要和最常见的疾病过程有关，包括败血症、急性肺损伤和多器官衰竭。鉴于 NO 无处不在、高度扩散和反应性强，其调节非常复杂。细胞内外的 NO 浓度、动力学和定位显然是至关重要的因素。在本更新中，我们回顾了一些研究，这些研究提供了关于这些复杂但重要问题的重要信息。解释这些和其他旨在阐明 NO 的生理和病理生理作用的研究必须考虑到这种复杂性。由于篇幅所限，本综述无法涵盖 NO 在这些疾病中的作用；本文将重点介绍理解 NO 在健康和疾病中复杂作用的最新进展。
