Alternations of Transient Outward K+ Current (Ito) in Type 2 Diabetic Ventricular Cardiomyocytes

• Sato Tatsuya

  Department of Cellular Physiology and Signal Transduction, Sapporo Medical University Second Department of Internal Medicine, Sapporo Medical University

• Kobayashi Takeshi

  Department of Cellular Physiology and Signal Transduction, Sapporo Medical University

• Miura Tetsuji

  Second Department of Internal Medicine, Sapporo Medical University

• Tohse Noritsugu

  Department of Cellular Physiology and Signal Transduction, Sapporo Medical University

書誌事項

タイトル別名

• Alternations of Transient Outward K<SUP>+</SUP> Current (I<SUB>to</SUB>) in Type 2 Diabetic Ventricular Cardiomyocytes

抄録

Background: Although cardiac ion channel remodeling has been reported in type 1 diabetes mellitus (T1DM), modification of the channels by type 2 DM (T2DM) is poorly understood. Here we characterized ion channel properties in cardiomyocytes of OLETF, a rat model of obese T2DM. Methods and Results: We isolated myocytes from subepicardial (EPI) and subendocardial (END) regions of the left ventricle for whole-cell patch clamp experiments. Action potential duration at 50% repolarization (APD₅₀) at 1 Hz was significantly longer in OLETF than in non-diabetic control (LETO) (EPI; 8.89±1.04 vs. 5.20±0.75 ms, END; 22.01±3.64 vs. 9.89±1.74 ms). In both EPI and END, L-type Ca²⁺ current and inward rectifier K⁺ current were similar between OLETF and LETO. In EPI, transient outward K⁺ current (I_to) density at 0.1 Hz was similar. However, the fast recovering component from inactivation of I_to was significantly decreased in OLETF. In END, I_to density at 0.1 Hz was significantly reduced in OLETF (8.77±0.78 vs. 14.50±1.31 pA/pF at +60 mV), in addition to slower recovery of I_to. Membrane capacitances were similar in all groups. Conclusions: T2DM slowed I_to recovery form inactivation and decreased END-I_to density without cardiomyocyte hypertrophy. This regional difference in the effect on I_to has not been reported for T1DM and appears characteristic to T2DM.

収録刊行物

• Journal of Arrhythmia

  Journal of Arrhythmia 27 (Supplement), OP43_3-OP43_3, 2011

  日本不整脈学会

キーワード

• diabetic cardiomyopathy
• transient outward potassium current
• action potential

詳細情報

• CRID: 1390282680221468928
• NII論文ID: 130002130172
• DOI: 10.4020/jhrs.27.op43_3
• ISSN: 18832148
• ISSN: 18804276
• Web Site: https://onlinelibrary.wiley.com/doi/full/10.4020/jhrs.27.OP43_3
• Web Site: https://search.jamas.or.jp/link/ui/2013138184
• 本文言語コード: en
• データソース種別:
  • JaLC
  • Crossref
  • CiNii Articles
• 抄録ライセンスフラグ: 使用不可