Biomaterial Database

Nasal contribution to exhaled nitric oxide at rest and during breathholding in humans. 1996

B Kimberly, and B Nejadnik, and G D Giraud, and W E Holden

Medical Service, Portland Veterans Administration Medical Center, Oregon 97201, USA.

We characterized the nasal contribution to exhaled nitric oxide (NO) at rest and during breathholding in humans. Exhaled NO was greater during nose breathing (141 +/- 17 nl/min/M2, mean +/- SEM) compared with mouth breathing (68 +/- 6 nl/min/M2, n = 8, p < 0.001). After voluntary closure of the soft palate (VCSP) to eliminate nasal NO, exhaled NO from the mouth decreased further (30 +/- 4 nl/min/M2, p < 0.001). Release of NO into nasal passages during VCSP (217 +/- 19 nl/min/M2) was greater than exhaled NO during nasal breathing (141 +/- 17 nl/min/m2, p < 0.001), suggesting that nasal NO is taken up by the respiratory tract. During mouth breathing or nose breathing, NO concentrations sampled with a bronchoscope were higher in the nasopharynx than at the epiglottis or in the trachea in five subjects. Increased peak exhaled NO after a breathhold (33 +/- 7 ppb) was reduced (10 +/- 4 ppb, p < 0.001) after balloon occlusion of the nasopharynx. NO concentration during breathholding increased to a greater extent in the nasopharynx than in the pharynx or trachea. We conclude that the majority of exhaled NO at rest and during a breathhold originates in the nasopharynx.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D008875	Middle Aged	An adult aged 45 - 64 years.	Middle Age
D009058	Mouth Breathing	Abnormal breathing through the mouth, usually associated with obstructive disorders of the nasal passages.	Breathing, Mouth,Breathings, Mouth,Mouth Breathings
D009297	Nasal Mucosa	The mucous lining of the NASAL CAVITY, including lining of the nostril (vestibule) and the OLFACTORY MUCOSA. Nasal mucosa consists of ciliated cells, GOBLET CELLS, brush cells, small granule cells, basal cells (STEM CELLS) and glands containing both mucous and serous cells.	Nasal Epithelium,Schneiderian Membrane,Epithelium, Nasal,Membrane, Schneiderian,Mucosa, Nasal
D009305	Nasopharynx	The top portion of the pharynx situated posterior to the nose and superior to the SOFT PALATE. The nasopharynx is the posterior extension of the nasal cavities and has a respiratory function.	Rhinopharynx,Choanae,Nasopharynges,Nasopharynxes,Rhinopharynges,Rhinopharynxes
D009569	Nitric Oxide	A free radical gas produced endogenously by a variety of mammalian cells, synthesized from ARGININE by NITRIC OXIDE SYNTHASE. Nitric oxide is one of the ENDOTHELIUM-DEPENDENT RELAXING FACTORS released by the vascular endothelium and mediates VASODILATION. It also inhibits platelet aggregation, induces disaggregation of aggregated platelets, and inhibits platelet adhesion to the vascular endothelium. Nitric oxide activates cytosolic GUANYLATE CYCLASE and thus elevates intracellular levels of CYCLIC GMP.	Endogenous Nitrate Vasodilator,Mononitrogen Monoxide,Nitric Oxide, Endothelium-Derived,Nitrogen Monoxide,Endothelium-Derived Nitric Oxide,Monoxide, Mononitrogen,Monoxide, Nitrogen,Nitrate Vasodilator, Endogenous,Nitric Oxide, Endothelium Derived,Oxide, Nitric,Vasodilator, Endogenous Nitrate
D010614	Pharynx	A funnel-shaped fibromuscular tube that conducts food to the ESOPHAGUS, and air to the LARYNX and LUNGS. It is located posterior to the NASAL CAVITY; ORAL CAVITY; and LARYNX, and extends from the SKULL BASE to the inferior border of the CRICOID CARTILAGE anteriorly and to the inferior border of the C6 vertebra posteriorly. It is divided into the NASOPHARYNX; OROPHARYNX; and HYPOPHARYNX (laryngopharynx).	Throat,Pharynxs,Throats
D012119	Respiration	The act of breathing with the LUNGS, consisting of INHALATION, or the taking into the lungs of the ambient air, and of EXHALATION, or the expelling of the modified air which contains more CARBON DIOXIDE than the air taken in (Blakiston's Gould Medical Dictionary, 4th ed.). This does not include tissue respiration (	Breathing
D002245	Carbon Dioxide	A colorless, odorless gas that can be formed by the body and is necessary for the respiration cycle of plants and animals.	Carbonic Anhydride,Anhydride, Carbonic,Dioxide, Carbon
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man