A flow-activated chloride-selective membrane current in vascular endothelial cells
A I Barakat1, E V Leaver, P A Pappone
1Department of Mechanical and Aeronautical Engineering, University of California, Davis, CA 95616, USA. abarakat@ucdavis.edu
Circulation Research
|October 26, 1999
Summary
Laminar flow activates both potassium (K+) and chloride (Cl-) ion channels in endothelial cells, influencing vascular tone. The balance between these flow-activated currents determines the net change in cell membrane potential.
Area of Science:
- Cardiovascular physiology
- Endothelial cell biology
- Mechanotransduction
Background:
- Shear stress from blood flow activates endothelial ion channels, a key early step in vascular tone regulation.
- Understanding these responses is crucial for comprehending vascular health and disease.
Purpose of the Study:
- To investigate the effects of laminar flow on endothelial cell membrane potential.
- To identify the specific ion channels involved in the endothelial response to flow.
Main Methods:
- In vitro study using human endothelial cells.
- Fluorescent potentiometric dye measurements.
- Whole-cell patch-clamp recordings.
Main Results:
- Laminar flow induced an initial membrane hyperpolarization followed by depolarization.
- A chloride (Cl-)-selective current, activated by flow, caused the depolarization.
- Flow also activated a potassium (K+) current, leading to hyperpolarization.
- The net membrane potential change resulted from the interplay of K+ and Cl- currents.
- Cellular adaptation to flow (preconditioning) did not alter the membrane potential response.
Conclusions:
- Endothelial cells possess distinct K+ and Cl- currents activated by laminar flow.
- The balance of these ion currents regulates endothelial membrane potential under flow conditions.
- These findings provide insight into the mechanotransduction pathways governing vascular tone.
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