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Vasodilation by shear-induced platelet aggregation in extracorporeal circuits
P Borgdorff1, W E Kok, M A Vis
1Laboratory for Physiology, Free University, Amsterdam, The Netherlands.
The American Journal of Physiology
|March 1, 1994
Summary
High shear stress during extracorporeal circulation causes platelet aggregation and serotonin release, leading to vasodilation. This study identifies serotonin as a key vasodilator released from aggregating platelets under shear stress.
Area of Science:
- Cardiovascular physiology
- Hemodynamics
- Platelet biology
Background:
- Extracorporeal circulation can negatively impact vascular reactivity.
- Albumin-coated tubes were used to mitigate these adverse effects in rat models.
Purpose of the Study:
- To investigate the origin of a vasodilator released during partial occlusion of an albumin-coated perfusion line.
- To determine if platelet aggregation under high shear stress is responsible for the observed vasodilation.
Main Methods:
- Partial occlusion of a carotid-femoral artery perfusion line in rats.
- Photometric monitoring of platelet aggregation and blood flow.
- Pharmacological blockade of serotonin receptors and von Willebrand factor pathways.
Main Results:
- Partial occlusion induced platelet aggregation distal to the occlusion site.
- Platelet aggregation preceded the increase in blood flow.
- Serotonin receptor blockade and inhibition of von Willebrand factor binding abolished the flow response.
Conclusions:
- Shear stress-induced platelet aggregation releases serotonin.
- Serotonin mediates the vasodilation observed during partial tube occlusion.
- Findings suggest a mechanism for vasodilation in extracorporeal circuits.