[Calcium activated non-selective cation channel in endothelial cell line ECV304 and inhibition of tumor necrosis factor-alpha].
OBJECTIVE
To study the character of non-selective cation channel in human umbilical cord vein endothelial cell line ECV304 and the effect of tumor necrosis factor-alpha (TNF-alpha) on channel activity.


METHODS
Patch clamp technique was used to record single channel and whole cell currents.


RESULTS
This channel can be activated by calcium, channel conductance was (19.74 +/- 2.35) pS and its Po was 0.260 +/- 0.006 (n = 5). 100 U/ml TNF-alpha inhibited channel activity, showing that conductance reduced to (10.69 +/- 4.68) pS and Po reduced to 0.230 +/- 0.051 (n = 5). Results in whole-cell configuration were consistent with that in cell-attached patches. Currents were obviously blocked by Cl- channel inhibitor anthracene-9-carboxylic acid (A9C). In order to testify the character of this channel further, KCl and NaCl were exchanged by K(+)-Aspartate in pipette solution. Under this condition, the single channel activities as before were recorded again. Its conductance was (18.33 +/- 2.98) pS(n = 8), and TNF-alpha as well as A9C could inhibit channel activity. But this channel activity could not be blocked by another Cl- channel blocker Zn2+. In the condition of K-Asparate replaced by CsCl in solution, identical channel activity as before could not be recorded. It seemed that Cs+ could not pass through this cation channel.


CONCLUSIONS
It is inferred that calcium-activated non-selective-action channel recorded in endothelial cell ECV304, can be inhibited by TNF-alpha and A9C.
Bao
G
G
Department of Biophysics, Institute of Basic Medical Sciences, CAMS and PUMC, Beijing 100005, China.
Yu
D
D
Lin
L
L
Zheng
Y
Y
D000873:Anthracenes / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000166:cytology*; D006801:Humans; D007473:Ion Channels / Q000187:drug effects / Q000378:metabolism; D018408:Patch-Clamp Techniques; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D014471:Umbilical Veins / Q000166:cytology
D000873:Anthracenes; D007473:Ion Channels; D014409:Tumor Necrosis Factor-alpha; C010030:9-anthroic acid; D002118:Calcium