1. Department of Physiology, School of Medicine, Showa University, Shinagawa-ku, Tokyo 142–8555, Japan
2. Department of Physiology, School of Medicine, Showa University, 1–5–8 Hatanodai, Shinagawa-ku, Tokyo 142–8555, Japan
3. Department of Otolaryngology, School of Medicine, Showa University, Shinagawa-ku, Tokyo 142–8555, Japan