[The cellular mechanism of angiotensin II inhibition on BKCa of ECV304 cell and the protective effect of gingko leaf extract].
OBJECTIVE
To observe the cellular mechanism of A II inhibition on Maxi-conductance calcium activated potassium channel (BKCa) in ECV304 cell membrane.


METHODS
Using the cell-attached configuration of patch clamp technique.


RESULTS
A II receptor antagonist saralasin (10(-7) mol/L) may block the inhibitory effect of A II (10(-7) mol/L). Phorbol ester (5 x 10(-8) mol/L) potentiated the effect of A II, while NO (10(-10) mol/L SNP) decreased the effect of A II and gingko leaf extract (800 micrograms/ml) activated BKCa and opposed the effects of A II.


CONCLUSIONS
A II receptor mediates the inhibitory effect of A II on BKCa in ECV304, and PKC is involved in this inhibition. NO and ginkgo leaf extract protect BKCa from the inhibition of A II.
Lin
L
L
Department of Physiology, Institute of Basic Medical Sciences, CAMS, PUMC, Beijing 100005, China.
Zheng
Y F
YF
Qu
J H
JH
Bao
G H
GH
D000804:Angiotensin II / Q000494:pharmacology*; D002478:Cells, Cultured; D004365:Drugs, Chinese Herbal / Q000494:pharmacology*; D020441:Ginkgo biloba / Q000737:chemistry*; D006801:Humans; D009569:Nitric Oxide / Q000494:pharmacology; D018408:Patch-Clamp Techniques; D018515:Plant Leaves / Q000737:chemistry; D024681:Potassium Channels, Calcium-Activated / Q000187:drug effects* / Q000502:physiology; D011493:Protein Kinase C / Q000502:physiology; D011945:Receptors, Angiotensin / Q000502:physiology; D014471:Umbilical Veins / Q000166:cytology
D004365:Drugs, Chinese Herbal; D024681:Potassium Channels, Calcium-Activated; D011945:Receptors, Angiotensin; D000804:Angiotensin II; D009569:Nitric Oxide; D011493:Protein Kinase C