1. Department of Veterinary Pharmacology, Faculty of Agriculture, Miyazaki University, Miyazaki 889‐2192
2. Frontier 21 Project, Institute for Life Science Research, Asahi Kasei Corporation, Fuji, Shizuoka 416‐8501
3. Department of Pharmacology, Faculty of Pharmacy, Kitasato University, Tokyo 108‐8641
4. Department of Physiology, Kanazawa University School of Medicine, Kanazawa, Ishikawa 920‐8640, Japan