Related Experiment Video
Updated: May 28, 2026
12:48
Microperfusion Technique to Investigate Regulation of Microvessel Permeability in Rat Mesentery
Published on: September 12, 2015
Evidence for active control of perfusion within lung microvessels
Kal E Watson1, William F Dovi, Robert L Conhaim
1The William S. Middleton Memorial Veterans Hospital, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA.
Journal of Applied Physiology (Bethesda, Md. : 1985)
|October 15, 2011
Summary
Pulmonary microvessels actively control blood flow, not just passively reacting. Different vasoconstrictors reveal distinct mechanisms, suggesting complex regulation of lung perfusion.
Area of Science:
- Physiology
- Pulmonary Circulation
- Endothelial Cell Biology
Background:
- Vasoconstrictors induce pulmonary microvascular endothelial cell contraction in vitro.
- This raises questions about whether in situ contraction actively controls microvascular perfusion.
- It challenges the notion of pulmonary microvessels as solely passive tubes regulated by arterioles.
Purpose of the Study:
- To investigate if pulmonary microvessels actively regulate perfusion.
- To determine if vasoconstrictor-induced endothelial cell contraction impacts microvascular function.
- To differentiate the mechanisms of action for various vasoconstrictors in the pulmonary circulation.
Main Methods:
- Isolated perfused rat lungs were used.
- Lungs were vasoconstricted with angiotensin II, bradykinin, serotonin, or U46619 at equal flow rates.
- Particle (3 μm) infusion was used to assess microvascular occlusion and trapping patterns.
Main Results:
- Angiotensin II and bradykinin significantly reduced venous particle concentration compared to U46619.
- Particle trapping and clustering were significantly greater with angiotensin II, bradykinin, and serotonin compared to U46619 and controls.
- These findings indicate differential effects of vasoconstrictors on pulmonary microvascular function.
Conclusions:
- Pulmonary microvessels exhibit active control over perfusion, not merely passive exchange.
- The studied vasoconstrictors likely operate through distinct mechanisms.
- These results support a more dynamic role for pulmonary microvessels in regulating blood flow.
