[G-protein potentiates the activation of TNF-alpha on calcium-activated potassium channel in ECV304].
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.


METHODS
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.
Lin
L
L
Department of Physiology, Institute of Basic Medical Sciences, CAMS, PUMC, Beijing 100005, China.
Zheng
Y
Y
Qu
J
J
Bao
G
G
D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D019204:GTP-Binding Proteins / Q000502:physiology*; D006801:Humans; D011188:Potassium / Q000378:metabolism; D024681:Potassium Channels, Calcium-Activated / Q000187:drug effects* / Q000502:physiology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D014471:Umbilical Veins / Q000166:cytology
D024681:Potassium Channels, Calcium-Activated; D014409:Tumor Necrosis Factor-alpha; D019204:GTP-Binding Proteins; D011188:Potassium; D002118:Calcium