Methacholine-induced bronchoconstriction in rats: effects of intravenous vs. aerosol delivery

Peták, Ferenc; Hantos, Zoltán; Adamicza, A.; Asztalos, T.; Sly, Peter D.

doi:10.1152/jappl.1997.82.5.1479

Cited by 162 publications

(190 citation statements)

References 29 publications

Supporting

Mentioning

168

Contrasting

Unclassified

Order By: Relevance

“…The average contribution of the chest wall to R was 6%, and the average contribution to G was 20%. These contributions are of similar proportions to studies that used similar techniques in other species, including rats (14) and human infants (Z. Hantos and P. Sly, unpublished observations). Perhaps surprisingly, our results suggest that the elastic properties of the chest wall do not contribute to the elastic behavior of the respiratory system.…”

Section: Discussionsupporting

confidence: 60%

“…Ventilation inhomogeneity with partial closure of some peripheral airways would be expected to result in an increase in G that is not matched by a similar increase in H and an increase in . Studies in rats undergoing methacholine challenge showed such a pattern (14) and confirmed that peripheral inhomogeneity was indeed responsible by ventilating the animals with a gas mixture of 20% oxygen and 80% neon and showing gas-dependent changes in G. We approached this possibility in several ways. We first considered that the volume history set by a PEEP of 2 cmH 2 O might not have been sufficient to prevent atelectasis and/or ventilation inhomogeneity from developing in our anesthetized, supine animals.…”

Section: Discussionmentioning

confidence: 75%

“…Under this paradigm, should only depend on the material composition of the tissue. Indeed, has been shown to be relatively constant across species and under a variety of experimental circumstances, although has been shown to increase in response to constrictor agonists both in vivo and in vitro (8,12,14) and to differ in magnitude between intact lungs and tissue strips (17). Sakai et al (17) measured in intact rats, after partial thoracotomy, achieved by opening the diaphragm to induce bilateral pneumothoraxes, in isolated lungs, and in tissue strips.…”

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Volume dependence of airway and tissue impedances in mice

Sly

Collins

Thamrin

et al. 2003

Journal of Applied Physiology

Self Cite

105

View full text Add to dashboard Cite

We measured respiratory input impedance (1–25 Hz) in mice and obtained parameters for airway and tissue mechanics by model fitting. Lung volume was varied by inflating to airway opening pressure (Pao) between 0 and 20 cmH2O. The expected pattern of changes in respiratory mechanics with increasing lung volume was seen: a progressive fall in airway resistance and increases in the coefficients of tissue damping and elastance. A surprising pattern was seen in hysteresivity (η), with a plateau at low lung volumes (Pao < 10 cmH2O), a sharp fall occurring between 10 and 15 cmH2O, and η approaching a second (lower) plateau at higher lung volumes. Studies designed to elucidate the mechanism(s) behind this behavior revealed that this was not due to chest wall properties, differences in volume history at low lung volume, time dependence of volume recruitment, or surface-acting forces. Our data are consistent with the notion that at low lung volumes the mechanics of the tissue matrix determine η, whereas at high lung volumes the properties of individual fibers (collagen) become more important.

show abstract

Section: Discussionsupporting

confidence: 60%

Section: Discussionmentioning

confidence: 75%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Volume dependence of airway and tissue impedances in mice

Sly

Collins

Thamrin

et al. 2003

Journal of Applied Physiology

Self Cite

105

View full text Add to dashboard Cite

show abstract

“…Suki et al (27) have reported that, in open-chest dogs, the pulmonary constrictor responses elicited by methacholine were diminished relative to those obtained in the same animals in closed-chest conditions. Petá k et al (22) have shown that the aerosol administration of methacholine produced greater elevations of Hti and Gti than those caused by the intravenous administration of methacholine. On histology, methacholine delivered as an aerosol has been shown to produce more heterogeneous reductions in airway diameters and greater distortion of the lung parenchyma compared with those associated with the intravenous administration of methacholine.…”

Section: Discussionmentioning

confidence: 99%

Frequency dependence of respiratory system mechanics during induced constriction in a murine model of asthma

Evans

Bond

Corry

et al. 2003

Journal of Applied Physiology

View full text Add to dashboard Cite

. Frequency dependence of respiratory system mechanics during induced constriction in a murine model of asthma. J Appl Physiol 94: 245-252, 2003; 10.1152/japplphysiol.00593.2002.-Airway dysfunction in asthma is characterized by hyperresponsiveness, heterogeneously narrowed airways, and closure of airways. To test the hypothesis that airway constriction in ovalbumin (OVA)-sensitized OVA-intranasally challenged (OVA/OVA) mice produces mechanical responses that are similar to those reported in asthmatic subjects, respiratory system resistance (Rrs) and elastance (Edyn,rs) spectra were obtained in OVA/OVA and control mice during intravenous methacholine (MCh) infusions. In control mice, MCh at 1,700 g ⅐ kg Ϫ1 ⅐ min Ϫ1 produced 1) a 495 and 928% increase of Rrs at 0.5 Hz and 19.75 Hz, respectively, 2) a 33% rise in Edyn,rs at 0.5 Hz, and 3) a mild frequency (f)-dependent increase of Edyn,rs. The same MCh dose in OVA/OVA mice produced 1) elevations of Rrs at 0.5 Hz and 19.75 Hz of 1,792 and 774%, respectively, 2) a 390% rise in Edyn,rs at 0.5 Hz, and 3) marked f-dependent increases of Edyn,rs. During constriction, the f dependence of mechanics in control mice was consistent with homogeneous airway narrowing; however, in OVA/OVA mice, f dependence was characteristic of heterogeneously narrowed airways, closure of airways, and airway shunting. These mechanisms amplify the pulmonary mechanical responses to constrictor stimuli at physiological breathing rates and have important roles in the pathophysiology of human asthma. airway closure; resistance; elastance; airway hyperresponsiveness AIRWAY NARROWING IS A MAJOR abnormality in the mechanism of diseases affecting pediatric and adult patients. Reductions in airway diameters can be predominately homogeneous or heterogeneous in nature; i.e., decreases in airway diameters can display a minimal or a large variability throughout the airway tree, respectively (5, 14). These categories of airway constriction bring about distinct patterns of frequency-dependent variations of lung mechanics. For example, homogeneously narrowed airways produce increases in lung resistance (RL) at physiological breathing rates that are commensurate to those of RL at high frequencies (5, 14). In contrast, heterogeneous airway narrowing is associated with increases of RL at physiological breathing rates that exceed those of RL at high frequencies (5, 14). Furthermore, a large variability in the reduction of airway caliber is more likely to produce closure of airways, which enhances the magnitude of dynamic lung elastance (Edyn,L) and may impair gas exchange.Pulmonary resistance and Edyn,L spectra obtained in subjects with severe asthma during periods of clinical stability and in subjects with mild or moderately severe asthma during agonist-induced constriction are consistent with a pattern of severe and heterogeneous airway constriction and closure of airways (11,12,15). These manifestations of airway dysfunction are of paramount clinical importance because marked elevations of RL and Edyn,L at phys...

show abstract

“…Briefly, Z rs was measured using a wave‐tube system 42 adapted for use in small animals 41 , 43 . Oscillatory signals consisting of nine non‐integer multiple frequency components between 4 and 38 Hz were delivered via a 1 m wave tube (internal diameter = 0·116 cm) to tracheostomized mice during brief apnoeic periods.…”

Section: Methodsmentioning

confidence: 99%

Acute diesel exhaust particle exposure increases viral titre and inflammation associated with existing influenza infection, but does not exacerbate deficits in lung function

Larcombe

Foong

Boylen

et al. 2012

Influenza Resp Viruses

View full text Add to dashboard Cite

Please cite this paper as: Larcombe et al. (2012) Acute diesel exhaust particle exposure increases viral titre and inflammation associated with existing influenza infection, but does not exacerbate deficits in lung function. Influenza and Other Respiratory Viruses DOI:10.1111/irv.12012. Background Exposure to diesel exhaust particles (DEP) is thought to exacerbate many pre‐existing respiratory diseases, including asthma, bronchitis and chronic obstructive pulmonary disease, however, there is a paucity of data on whether DEP exacerbates illness due to respiratory viral infection. Objectives To assess the physiological consequences of an acute DEP exposure during the peak of influenza‐induced illness. Methods We exposed adult female BALB/c mice to 100 μg DEP (or control) 3·75 days after infection with 104·5 plaque forming units of influenza A/Mem71 (or control). Six hours, 24 hours and 7 days after DEP exposure we measured thoracic gas volume and lung function at functional residual capacity. Bronchoalveolar lavage fluid was taken for analyses of cellular inflammation and cytokines, and whole lungs were taken for measurement of viral titre. Results Influenza infection resulted in significantly increased inflammation, cytokine influx and impairment to lung function. DEP exposure alone resulted in less inflammation and cytokine influx, and no impairment to lung function. Mice infected with influenza and exposed to DEP had higher viral titres and neutrophilia compared with infected mice, yet they did not have more impaired lung mechanics than mice infected with influenza alone. Conclusions A single dose of DEP is not sufficient to physiologically exacerbate pre‐existing respiratory disease caused by influenza infection in mice.

show abstract

Methacholine-induced bronchoconstriction in rats: effects of intravenous vs. aerosol delivery

Cited by 162 publications

References 29 publications

Volume dependence of airway and tissue impedances in mice

Volume dependence of airway and tissue impedances in mice

Frequency dependence of respiratory system mechanics during induced constriction in a murine model of asthma

Acute diesel exhaust particle exposure increases viral titre and inflammation associated with existing influenza infection, but does not exacerbate deficits in lung function

Contact Info

Product

Resources

About