1. Nihon University Graduated School of Dentistry at Matsudo, Cellular Physiology, Matsudo, Chiba 271-8587, Japan
2. Department of Physiology, Nihon University School of Dentistry at Matsudo, Matsudo, Chiba 271-8587, Japan
3. Research Institute of Oral Science, Nihon University School of Dentistry at Matuso, Matsudo, Chiba 271-8587, Japan