Document Detail


Effect of nitric oxide synthesis inhibition with nebulized L-NAME on ventilation-perfusion distributions in bronchial asthma.
MedLine Citation:
PMID:  9817160     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Patients with clinically stable asthma may show ventilation-perfusion (V'A/Q') mismatch. Nitric oxide (NO), a potent endogenous vasodilator, is increased in exhaled air of asthmatics. Such an increased NO production may be detrimental for optimal V'A/Q' balance owing to the potential inhibition of hypoxic pulmonary vasoconstriction. This study was undertaken to investigate the relationship between the concentration of NO in exhaled air and the degree of gas-exchange impairment and to assess the effect of nebulized N(G)-nitro-L-arginine methyl ester (L-NAME), a competitive inhibitor of NO synthesis, on gas exchange in patients with asthma. Twelve patients (four females and eight males, aged 31+/-5 yrs) with clinically stable asthma (forced expiratory volume in one second (FEV1) 80+/-5%) not treated with glucocorticoids and increased exhaled NO (58+/-9 parts per billion (ppb)) were studied. Exhaled NO, respiratory system resistance (Rrs), arterial blood gases and V'A/Q' distributions were measured before and 30, 60, 90 and 120 min after placebo or L-NAME (10(-1) M) nebulization; in eight patients pulmonary haemodynamics were also measured. At baseline no relationships between exhaled NO and gas-exchange measurements were shown. Nebulized L-NAME induced a significant decrease in exhaled NO (p< 0.001), which was maximal at 90 min (-55+/-5%). However, after L-NAME no changes in Rrs, arterial oxygen tension, the alveolar-arterial pressure difference in oxygen or V'A/Q' distributions were shown and nebulized L-NAME did not modify pulmonary artery pressure. In conclusion, the degree of gas-exchange impairment in stable asthma is not related to nitric oxide concentration in exhaled air and nitric oxide synthesis inhibition with N(G)-nitro-L-arginine methyl ester does not alter gas exchange or pulmonary haemodynamics, such that ventilation-perfusion disturbances do not appear to be related to an increased synthesis of nitric oxide in the airways.
Authors:
F P Gómez; J A Barberà; J Roca; R Iglesia; J Ribas; P J Barnes; R Rodriguez-Roisin
Publication Detail:
Type:  Clinical Trial; Journal Article; Randomized Controlled Trial; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The European respiratory journal     Volume:  12     ISSN:  0903-1936     ISO Abbreviation:  Eur. Respir. J.     Publication Date:  1998 Oct 
Date Detail:
Created Date:  1999-02-04     Completed Date:  1999-02-04     Revised Date:  2013-05-23    
Medline Journal Info:
Nlm Unique ID:  8803460     Medline TA:  Eur Respir J     Country:  DENMARK    
Other Details:
Languages:  eng     Pagination:  865-71     Citation Subset:  IM    
Affiliation:
Dept de Medicina, Institut d'Investigacions Biomèdiques August Pi i Sunyer, Hospital Clínic, Universitat de Barcelona, Spain.
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MeSH Terms
Descriptor/Qualifier:
Administration, Inhalation
Adult
Airway Resistance / drug effects*
Asthma / drug therapy*
Cross-Over Studies
Enzyme Inhibitors / administration & dosage*
Female
Humans
Male
NG-Nitroarginine Methyl Ester / administration & dosage*
Nitric Oxide / analysis,  metabolism*
Pulmonary Gas Exchange / drug effects
Reference Values
Ventilation-Perfusion Ratio / drug effects*
Chemical
Reg. No./Substance:
0/Enzyme Inhibitors; 10102-43-9/Nitric Oxide; 50903-99-6/NG-Nitroarginine Methyl Ester

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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