Dillon W C, Hampl V, Shultz P J, Rubins J B, Archer S L
Department of Medicine, VA Medical Center, Minneapolis, MN, USA.
Chest. 1996 Oct;110(4):930-8. doi: 10.1378/chest.110.4.930.
Nitric oxide (NO) exists in the human breath, but little is known about its site of origin or enzyme source. The aims of this study were to locate the main site of NO release into human breath and to decide whether the inducible isoform of NO synthase (iNOS) and nasal bacteria contribute to breath NO.
Using a chemiluminescence assay, NO levels were measured in air exhaled from the nose, mouth, trachea, and distal airway. The susceptibility of breath NO to treatment with a topical corticosteroid (to inhibit iNOS; intranasal beclomethasone dipropionate for 2 weeks) and with antibiotics (systemic amoxicillin plus clavulanic acid and intranasal bacitracin zinc, 5 to 10 days) was also tested.
Twenty-one healthy subjects, 9 intubated patients, and 7 patients undergoing bronchoscopy. All subjects were nonsmokers free of pneumonia, rhinitis, and bronchitis.
Breath NO levels, collected in the gas sampling bags, were greater (p < 0.05) in the nose (25 +/- 2 parts per billion [ppb]) than in the mouth (6 +/- 1 ppb), trachea (3 +/- 1 ppb), or distal airway (1 +/- 2 ppb). Similar results were obtained when NO was sampled directly by cannula from nose or mouth during resting breathing. Nasal breath NO signal increased sharply during 30 s of breath-holding. Beclomethasone, but not antibiotics, decreased nasal NO levels without changing oral breath NO.
Most NO in normal human breath derives locally from the nose where it can reach high levels during breath-holding. NO is synthesized, at least in part, by a steroid-inhibitable, nonbacterial, NO synthase, presumably iNOS.
一氧化氮（NO）存在于人体呼出的气体中，但其产生部位或酶源却鲜为人知。本研究的目的是确定NO释放到人体呼出气体中的主要部位，并判断诱导型一氧化氮合酶（iNOS）和鼻腔细菌是否对呼出气体中的NO有影响。
采用化学发光分析法，测量从鼻子、嘴巴、气管和远端气道呼出的空气中的NO水平。还测试了呼出气体中的NO对局部使用皮质类固醇（抑制iNOS；鼻内使用二丙酸倍氯米松2周）和抗生素（全身使用阿莫西林加克拉维酸以及鼻内使用杆菌肽锌，5至10天）治疗的敏感性。
21名健康受试者、9名插管患者和7名接受支气管镜检查的患者。所有受试者均为不吸烟者，无肺炎、鼻炎和支气管炎。
收集在气体采样袋中的呼出气体中的NO水平，鼻子（25±2十亿分之一[ppb]）高于嘴巴（6±1 ppb）、气管（3±1 ppb）或远端气道（1±2 ppb）（p<0.05）。在静息呼吸期间通过插管直接从鼻子或嘴巴采样NO时，也获得了类似的结果。屏气30秒期间，鼻腔呼出的NO信号急剧增加。倍氯米松可降低鼻腔NO水平，但抗生素无此作用，且口腔呼出气体中的NO未发生变化。
正常人体呼出气体中的大多数NO局部来源于鼻子，在屏气期间其水平可升高。NO至少部分是由一种类固醇可抑制的、非细菌性的一氧化氮合酶合成的，推测为iNOS。
