Document Detail

Distribution of airway narrowing during hyperpnea-induced bronchoconstriction in guinea pigs.
MedLine Citation:
PMID:  2262449     Owner:  NLM     Status:  MEDLINE    
Increasing minute ventilation of dry gas shifts the principal burden of respiratory heat and water losses from more proximal airway to airways farther into the lung. If these local thermal transfers determine the local stimulus for bronchoconstriction, then increasing minute ventilation of dry gas might also extend the zone of airway narrowing farther into the lung during hyperpnea-induced bronchoconstriction (HIB). We tested this hypothesis by comparing tantalum bronchograms in tracheostomized guinea pigs before and during bronchoconstriction induced by dry gas hyperpnea, intravenous methacholine, and intravenous capsaicin. In eight animals subjected to 5 min of dry gas isocapnic hyperpnea [tidal volume (VT) = 2-5 ml, 150 breaths/min], there was little change in the diameter of the trachea or the main stem bronchi up to 0.75 cm past the main carina (zone 1). In contrast, bronchi from 0.75 to 1.50 cm past the main carina (zone 2) narrowed progressively at all minute ventilations greater than or equal to 300 ml/min (VT = 2 ml). More distal bronchi (1.50-3.10 cm past the main carina; zone 3) did not narrow significantly until minute ventilation was raised to 450 ml/min (VT = 3 ml). The estimated VT during hyperpnea needed to elicit a 50% reduction in airway diameter was significantly higher in zone 3 bronchi [4.3 +/- 0.8 (SD) ml] than in zone 2 bronchi (3.5 +/- 1.1 ml, P less than 0.012).(ABSTRACT TRUNCATED AT 250 WORDS)
D W Ray; S Eappen; C Hernandez; M Jackson; L E Alger; A R Leff; J Solway
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  69     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  1990 Oct 
Date Detail:
Created Date:  1991-02-01     Completed Date:  1991-02-01     Revised Date:  2013-09-26    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol (1985)     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1323-9     Citation Subset:  IM    
Department of Medicine, University of Chicago, Illinois 60637.
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MeSH Terms
Bronchoconstriction / drug effects,  physiology*
Capsaicin / pharmacology
Dose-Response Relationship, Drug
Guinea Pigs
Methacholine Compounds / pharmacology
Respiration / drug effects,  physiology*
Respiratory Physiological Phenomena
Respiratory System / drug effects
Tantalum / diagnostic use
Trachea / physiology
Grant Support
Reg. No./Substance:
0/Methacholine Compounds; 404-86-4/Capsaicin; 7440-25-7/Tantalum

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