Effects of caffeine and ryanodine on KCa in porcine coronary artery smooth muscle cells
- VernacularTitle:在inside-out膜片上caffeine对猪冠状动脉平滑肌细胞钙激活钾通道的调节作用及ryanodine的影响
- Author:
Weigao ZHONG
;
Yan YANG
;
Xiaorong ZENG
;
Yue CUI
;
Tianhan KONG
- Publication Type:Journal Article
- Keywords:
Caffeine;
Potassium channels,calcium-activated;
Inside-out patches;
Ryanodine;
Porcine coronary artery smooth muscle cells;
Cell-attached patches
- From:
Chinese Journal of Pathophysiology
1986;0(01):-
- CountryChina
- Language:Chinese
-
Abstract:
AIM:To study the effect of caffeine on the large conductance calcium activated potassium (KCa) channels by patch-clamp technique on smooth muscle cells enzymatically isolated from the porcine coronary artery (PCASMC),and to investigate the effect of ryanodine on KCa being activated by caffeine.METHODS:Using the single channel patch-clamp technique,single PCASMC was isolated by collagenase,the activity of single KCa channel was recorded in porcine coronary artery smooth muscle cells.RESULTS:Caffeine (0.1-10 mmol/L) enhanced the open probability (Po) of KCa channels in a dose-dependent manner in the intracellular side of inside-out patches and its effect was almost completely abolished by washout. Caffeine decreased the mean close time markedly,but had no effect on the amplitude of KCa channels. However,ryanodine (10-40 ?mol/L) decreased Po of KCa channels activated by caffeine in a dose-dependent manner in cell-attached patches. The mean open time also decreased.CONCLUSION:Caffeine directly activates KCa channels of porcine coronary artery smooth muscle cells in inside-out patches,the activity of single KCa channel is inhibited by ryanodine indirectly in cell-attached patches.
