Abstract
There is evidence that the mode of smooth muscle agonist delivery affects the changes induced in lung mechanical properties. The object of this investigation was to study modifications in airway behaviour associated with different modes of agonist delivery. Tracheal (Ptr) and alveolar pressure (PA) and flow (V̇) were measured in open-chested, mechanically ventilated (f = 1 Hz, VT = 10 ml/kg, PEEP = 4 cm H2O) rats under baseline conditions and during administration of repeated intravenous (iv) bolus, iv continuous infusion and aerosols of methacholine (MCh). We calculated lung elastance (EL) and lung resistance (RL) by fitting the equation of motion to changes in Ptr and V̇. We assessed the patency of the airway pathways and local dynamic hyperinflation by comparing Ptr vs PA. Comparison of the three different modes of MCh delivery showed a difference in the functional behaviour of the airways. In the aerosol group a larger incidence of highly constricted airways was observed. Conversely, the iv groups showed a larger incidence of regional dynamic hyperinflation. In the bolus group a different time course in the development of dynamic hyperinflation was observed for different pathways within the same animal. For consecutive challenges a given pathway tended to behave in the same manner, suggesting the response was characteristic for that pathway. In this study we have shown that, even though different airway pathways show different intrinsic reactivity, the mode of agonist delivery plays a role in determining functional airway behaviour.
| Original language | English |
|---|---|
| Pages (from-to) | 71-80 |
| Number of pages | 10 |
| Journal | Respiration Physiology |
| Volume | 106 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - Oct 1996 |
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Keywords
- Airways, smooth muscle
- Mammals, rat
- Mechanics of breathing, tracheal, alveolar pressure
- Pharmacological agents, methacholine
- Pressure, alveolar, tracheal
- Smooth muscle agonists
- Smooth muscle, tracheal, agonist delivery
ASJC Scopus subject areas
- Physiology
- Pulmonary and Respiratory Medicine
Cite this
Effect of the route and mode of agonist delivery on functional behaviour of the airways. / Salerno, Francesco G.; Ludwig, Mara S.
In: Respiration Physiology, Vol. 106, No. 1, 10.1996, p. 71-80.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Effect of the route and mode of agonist delivery on functional behaviour of the airways
AU - Salerno, Francesco G.
AU - Ludwig, Mara S.
PY - 1996/10
Y1 - 1996/10
N2 - There is evidence that the mode of smooth muscle agonist delivery affects the changes induced in lung mechanical properties. The object of this investigation was to study modifications in airway behaviour associated with different modes of agonist delivery. Tracheal (Ptr) and alveolar pressure (PA) and flow (V̇) were measured in open-chested, mechanically ventilated (f = 1 Hz, VT = 10 ml/kg, PEEP = 4 cm H2O) rats under baseline conditions and during administration of repeated intravenous (iv) bolus, iv continuous infusion and aerosols of methacholine (MCh). We calculated lung elastance (EL) and lung resistance (RL) by fitting the equation of motion to changes in Ptr and V̇. We assessed the patency of the airway pathways and local dynamic hyperinflation by comparing Ptr vs PA. Comparison of the three different modes of MCh delivery showed a difference in the functional behaviour of the airways. In the aerosol group a larger incidence of highly constricted airways was observed. Conversely, the iv groups showed a larger incidence of regional dynamic hyperinflation. In the bolus group a different time course in the development of dynamic hyperinflation was observed for different pathways within the same animal. For consecutive challenges a given pathway tended to behave in the same manner, suggesting the response was characteristic for that pathway. In this study we have shown that, even though different airway pathways show different intrinsic reactivity, the mode of agonist delivery plays a role in determining functional airway behaviour.
AB - There is evidence that the mode of smooth muscle agonist delivery affects the changes induced in lung mechanical properties. The object of this investigation was to study modifications in airway behaviour associated with different modes of agonist delivery. Tracheal (Ptr) and alveolar pressure (PA) and flow (V̇) were measured in open-chested, mechanically ventilated (f = 1 Hz, VT = 10 ml/kg, PEEP = 4 cm H2O) rats under baseline conditions and during administration of repeated intravenous (iv) bolus, iv continuous infusion and aerosols of methacholine (MCh). We calculated lung elastance (EL) and lung resistance (RL) by fitting the equation of motion to changes in Ptr and V̇. We assessed the patency of the airway pathways and local dynamic hyperinflation by comparing Ptr vs PA. Comparison of the three different modes of MCh delivery showed a difference in the functional behaviour of the airways. In the aerosol group a larger incidence of highly constricted airways was observed. Conversely, the iv groups showed a larger incidence of regional dynamic hyperinflation. In the bolus group a different time course in the development of dynamic hyperinflation was observed for different pathways within the same animal. For consecutive challenges a given pathway tended to behave in the same manner, suggesting the response was characteristic for that pathway. In this study we have shown that, even though different airway pathways show different intrinsic reactivity, the mode of agonist delivery plays a role in determining functional airway behaviour.
KW - Airways, smooth muscle
KW - Mammals, rat
KW - Mechanics of breathing, tracheal, alveolar pressure
KW - Pharmacological agents, methacholine
KW - Pressure, alveolar, tracheal
KW - Smooth muscle agonists
KW - Smooth muscle, tracheal, agonist delivery
UR - http://www.scopus.com/inward/record.url?scp=0030273701&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0030273701&partnerID=8YFLogxK
U2 - 10.1016/0034-5687(96)00059-X
DO - 10.1016/0034-5687(96)00059-X
M3 - Article
C2 - 8946579
AN - SCOPUS:0030273701
VL - 106
SP - 71
EP - 80
JO - Respiration Physiology
JF - Respiration Physiology
SN - 0034-5687
IS - 1
ER -