Effects of caffeine and ryanodine on K_(Ca) 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
2010;26(1):53-58
- CountryChina
- Language:Chinese
-
Abstract:
AIM: To study the effect of caffeine on the large conductance calcium activated potassium (K_(Ca)) 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 K_(Ca) being activated by caffeine.METHODS: Using the single channel patch-clamp technique,single PCASMC was isolated by collagenase,the activity of single K_(Ca) channel was recorded in porcine coronary artery smooth muscle cells.RESULTS: Caffeine (0.1-10 mmol/L) enhanced the open probability (Po) of K_(Ca) 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 K_(Ca) channels. However,ryanodine (10-40 μmol/L) decreased Po of K_(Ca) channels activated by caffeine in a dose-dependent manner in cell-attached patches. The mean open time also decreased.CONCLUSION: Caffeine directly activates K_(Ca) channels of porcine coronary artery smooth muscle cells in inside-out patches,the activity of single K_(Ca) channel is inhibited by ryanodine indirectly in cell-attached patches.
