Changes of open probability of large conductance Ca2+-activated K+ channels in diabetic coronary smooth muscle cells of rats

Ru Xing Wang, 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

Research output: Contribution to journalArticle

2 Scopus citations

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.

Original languageEnglish (US)
Pages (from-to)770-774
Number of pages5
JournalChinese Journal of Cardiology
Volume40
Issue number9
DOIs
StatePublished - Sep 1 2012

Keywords

  • Coronary vessels
  • Diabetes mellitus
  • Large-conductance calcium-activated potassium channels
  • Myocytes, smooth muscle
  • Patch-clamp techniques

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine

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