Changes of open probability of large conductance Ca2+ -activated K+ channels in diabetic coronary smooth muscle cells of rats
10.3760/cma.j.issn.0253-3758.2012.09.011
- VernacularTitle:糖尿病大鼠冠状动脉平滑肌细胞大电导钙激活钾通道开放概率的变化
- Author:
Ru-Xing WANG
1
;
Zhi-Ming YU
;
Chang-Ying ZHANG
;
Jie ZHENG
;
Ku-Lin LI
;
Yun-Lai GAO
;
Ying-Fang BAO
;
Ying WU
;
Yong YAO
;
Xiao-Rong LI
;
Tong LU
Author Information
1. 南京医科大学附属无锡市人民医院
- Keywords:
Diabetes mellitus;
Coronary vessels;
Myocytes,smooth muscle;
Largeconductance calcium-activated potassium channels;
Patch-clamp techniques
- From:
Chinese Journal of Cardiology
2012;40(9):770-774
- CountryChina
- Language:Chinese
-
Abstract:
Objective To investigate the changes of open probability (Po) of large conductance Ca2+ -activated K + channel (BK channel ) in diabetic coronary smooth muscle cells and elucidate the underlying cellular electrophysiology mechanisms of coronary dysfunction.Methods Rat coronary smooth muscle cells were isolated from control group and diabetic group.BK single channel currents were recorded by patch clamp technique in inside-out configuration.Open probabilities were calculated and compared between two groups.After exposure to DHS-1,a specific BK channel activator,Po at 0.2 and 1 μmoL/L free Ca2+ were compared between control and diabetic groups.Results In the presence of 0.2 μmol/L free Ca2+,the Po at baseline was significantly lower in diabetic rats than in control rats (0.0032 ± 0.0012 vs.0.095 ±0.036,P ＜ 0.05).Cytoplasmic application of DSH-1 significantly increased the Po to 0.335 ±0.096 (P ＜0.05 vs.baseline) in control rats,whereas DSH-1 had no effect in diabetic rats ( Po =0.022 ±0.018,P＞0.05 vs.baseline).In the presence of 1 μmol/L free Ca2+,the Po at baseline was also significantly lower in diabetic rats than in control rats (0.210 ± 0.055 vs.0.458 ± 0.077,P ＜ 0.05 ).Cytoplasmic application of DHS-1 further robustly enhanced Po to 0.823 ± 0.019 (P ＜ 0.05 vs.baseline) in control rats and to 0.446 ± 0.098 in diabetic rats ( P ＜ 0.05 vs.baseline of diabetic rats; P ＜ 0.05 vs.control rats with DHS-1 ).Conclusion The decrease of Po of BK single channel in coronary smooth muscle cells may be a potential cause for coronary dysfunction in diabetic rats.
