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Updated: Aug 8, 2026

Characterization of G Protein-coupled Receptors by a Fluorescence-based Calcium Mobilization Assay
Published on: July 28, 2014
[G-protein potentiates the activation of TNF-alpha on calcium-activated potassium channel in ECV304]
1Department of Physiology, Institute of Basic Medical Sciences, CAMS, PUMC, Beijing 100005, China.
Objective:
Observe the effect of tumor necrosis factor-alpha (TNF-alpha) on calcium-activated potassium channel in ECV304 and the possible involvement of G-protein mediation in the action of TNF-alpha.
Method:
Using the cell-attached configuration of patch clamp technique.
Results:
(1) the activity of high-conductance calcium-activated potassium channel (BKca) was recorded. Its conductance is (202.54 +/- 16.62) pS; (2) the activity of BKca was potentiated by 200 U/ml TNF-alpha; (3) G-protein would intensify this TNF-alpha activation.
Conclusions:
TNF-alpha acted on vascular endothelial cell ECV304 could rapidly activate the activity of BKca. Opening of BKca resulted in membrane hyper-polarization which could increase electro-chemical gradient for the resting Ca2+ influx and open leakage calcium channel, thus resting cytoplasmic free Ca2+ concentration could be elevated. G-protein may exert an important regulation in this process.
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