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Endothelial cell calcium increases during flow-induced dilation in isolated arterioles
J C Falcone1, L Kuo, G A Meininger
1Department of Medical Physiology, Texas A&M University Health Science Center, College Station 77843-1114.
The American Journal of Physiology
|February 1, 1993
Summary
Flowing blood elevates endothelial intracellular calcium, causing blood vessels to widen. This study reveals calcium
Area of Science:
- Physiology
- Cardiovascular Research
- Cell Biology
Background:
- Endothelial cells play a crucial role in regulating vascular tone.
- Intracellular calcium concentration ([Ca2+]i) is a key signaling molecule in endothelial cells.
- Understanding the mechanisms of flow-induced vasodilation is vital for cardiovascular health.
Purpose of the Study:
- To investigate the role of endothelial intracellular calcium in flow-mediated and agonist-induced vasodilation in intact arterioles.
- To determine whether calcium signaling is essential for endothelium-dependent responses.
Main Methods:
- Intact, isolated arterioles were used.
- Endothelial cells were loaded with the calcium-sensitive fluorescent dye fura-2.
- A fluorescence microscope and digital image processor measured fura-2 fluorescence and microvessel diameter simultaneously.
Main Results:
- Arterial flow significantly increased endothelial [Ca2+]i and caused vasodilation.
- Acetylcholine increased endothelial [Ca2+]i and induced vasodilation.
- Adenosine dilated arterioles without altering endothelial [Ca2+]i.
- Endothelium removal abolished responses to flow and acetylcholine, but not adenosine.
Conclusions:
- Endothelial calcium signaling is critical for flow-induced and acetylcholine-mediated vasodilation in arterioles.
- Adenosine-induced vasodilation may involve calcium-independent pathways.
- Studying endothelial function in intact vessels is essential for understanding vascular regulation.