The mechanisms od action of Shakuyakukanzoto to reduce muscle pain

2013 Fiscal Year Final Research Report

• Project/Area Number: 24659701
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Single-year Grants
• Research Field: Anesthesiology/Resuscitation studies
• Research Institution: Fukushima Medical University
• Principal Investigator: ISEKI Yuzo 福島県立医科大学, 医学部, 助手 (60622313)
• Project Period (FY): 2012-04-01 – 2014-03-31
• Keywords: 芍薬甘草湯 / 芍薬 / 甘草 / ポタシウム電流 / ホールセルクランプ法 / H9ｃ２細胞 / ポタシウム電流

Research Abstract

Shakuyakukanzoto is a commonly used for the treatment of acute pain associated with muscle cramp. In the present study using the whole-cell patch clamp technique, we examined effects of Shakuyakukanzoto on the ultra-rapidly activating slowly inactivating delayed rectifier K+ current (IKur) in H9c2 cells, that is a cell line derived from embryonic rat heart, and can differentiate into skeletal myocytes. Shakuyakukanzoto inhibited IKur in a concentration-dependent manner. The half-maximal concentration (IC50) was approximately 1.3 mg/ml and the Hill coefficient was 1.2. The order of potency of inhibiting IKur was Kanzo> Shakuyakukanzoto> Shakuyaku. Glycyrrhizin, which is a major component of Kanzo, had no inhibitory effect on IKur. Our result suggest that Shakuyakukanzoto may normalize intracellular and extracellular K+ balance by inhibiting IKur and reducing K+ efflux. This may be a part of the mechanism that Shakuyakukanzoto improving muscle pain.