An in vitro study examining the duration between deep inspirations on the rate of renarrowing.

TitleAn in vitro study examining the duration between deep inspirations on the rate of renarrowing.
Publication TypeJournal Article
Year of Publication2017
AuteursMailhot-Larouche, S, Lortie, K, Marsolais, D, Flamand, N, Bossé, Y
JournalRespir Physiol Neurobiol
Volume243
Pagination13-19
Date Published2017 09
ISSN1878-1519
KeywordsAnimals, Bronchi, Bronchoconstriction, Bronchoconstrictor Agents, Bronchodilator Agents, Dose-Response Relationship, Drug, Female, Guinea Pigs, In Vitro Techniques, Isoproterenol, Methacholine Chloride, Muscle Contraction, Muscle, Smooth, Parenchymal Tissue, Time Factors
Abstract

The factors altering the bronchodilatory response to a deep inspiration (DI) in asthma are important to decipher. In this in vitro study, we investigated the effect of changing the duration between DIs on the rate of force recovery post-DI in guinea pig bronchi. The airway smooth muscle (ASM) within the main bronchi were submitted to length oscillation that simulated tidal breathing in different contractile states during 2, 5, 10 or 30min prior to a larger length excursion that simulated a DI. The contractile states of ASM were determined by adding either methacholine or isoproterenol. Irrespective of the contractile state, the duration between DIs neither affected the measured force during length oscillation nor the bronchodilator effect of DI. Contrastingly, the rate of force recovery post-DI in contracted state increased as the duration between DIs decreased. Similar results were obtained with contracted parenchymal strips. These findings suggest that changing the duration between DIs may alter the rate of ASM force recovery post-DI and thereby affect the rate of renarrowing and the duration of the respiratory relief afforded by DI.

DOI10.1016/j.resp.2017.04.013
Alternate JournalRespir Physiol Neurobiol
PubMed ID28487171