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Flow-induced vasodilation in the ferret lung
J H Chammas1, D A Rickaby, M Guarin
1Department of Surgery, Medical College of Wisconsin, Milwaukee 53226, USA.
Journal of Applied Physiology (Bethesda, Md. : 1985)
|August 1, 1997
Summary
Shear stress may stimulate pulmonary vasodilation. In isolated ferret lungs, increased blood flow dilated small pulmonary arteries under hypoxic conditions, suggesting shear stress is a vasodilator.
Area of Science:
- Pulmonary circulation physiology
- Vascular mechanics
Background:
- Pulmonary arteries regulate blood flow and pressure.
- Vascular tone influences pulmonary artery diameter.
Purpose of the Study:
- To investigate if shear stress acts as a pulmonary vasodilator.
- To determine the effect of blood flow changes on small pulmonary artery diameter.
Main Methods:
- Isolated perfused ferret lung lobes were used.
- Microfocal X-ray imaging measured arterial diameters (0.3-1.3 mm).
- Blood flow was altered (10 vs. 40 ml/min) at constant pressure under normoxic and hypoxic conditions.
Main Results:
- Under normoxia, flow changes had minimal effect on arterial diameter.
- Under hypoxia, higher blood flow led to larger arterial diameters at constant pressure.
- Results indicate shear stress is a pulmonary vasodilator stimulus.
Conclusions:
- Shear stress is a potential stimulus for pulmonary vasodilation.
- This mechanism may play a role in regulating pulmonary blood flow.