1. Department of Physiology, Division of Integrative Physiology, Jichi Medical University School of Medicine, Shimotsuke 329-0498, Japan
2. Depertment of Internal medicine, Division of Cardiovascular Medicine, Jichi Medical University School of Medicine, Shimotsuke 329-0498, Japan
3. Department of General Internal Medicine, Saitama Medical School, Saitama 350-0495, Japan