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Apamin-sensitive Ca2+-dependent K+ current and hyperpolarization in human endothelial cells
1Department of Chemical Pharmacology, Faculty of Pharmaceutical Sciences, Nagoya City University, Mizuhoku, Nagoya, Japan.
Biochemical and Biophysical Research Communications
|July 18, 1997
Summary
Histamine activates apamin-sensitive calcium-dependent potassium current (I(K-Ca)) in human umbilical vein endothelial cells (HUVECs). This suggests specific potassium channels are involved in endothelial cell responses to receptor stimulation.
Area of Science:
- Physiology
- Molecular Biology
- Endothelial Cell Biology
Background:
- Vascular endothelial cells possess various calcium-dependent potassium currents (I(K-Ca)).
- Histamine is a known signaling molecule that affects endothelial cell function.
Purpose of the Study:
- To investigate the presence and role of apamin-sensitive I(K-Ca) in human umbilical vein endothelial cells (HUVECs).
- To determine if histamine activates specific types of I(K-Ca) in HUVECs.
Main Methods:
- Electrophysiological recordings of I(K-Ca) in HUVECs.
- Application of histamine to stimulate endothelial cells.
- Pharmacological blockade of potassium channels using apamin, tetraethylammonium, and iberiotoxin.
Main Results:
- Histamine treatment activated apamin-sensitive I(K-Ca) in 65% of HUVECs.
- Apamin significantly inhibited histamine-induced I(K-Ca) and hyperpolarization.
- Non-selective and large-conductance calcium-dependent potassium channel blockers showed minimal effects.
Conclusions:
- Apamin-sensitive calcium-dependent potassium channels are expressed in HUVECs.
- These channels are activated by histamine receptor stimulation, suggesting a role in endothelial cell signaling.