1. Faculty of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-Honmachi, Kumamoto 862, Japan, Seiwa Pharmaceutical. Ltd., 187-11 Usuba, Hanakawa-machi, Kitaibaraki-shi, Ibaraki 319-15, Japan, Beijing University of Traditional Chinese Medicine and Pharmacy, Beijing 100029, People's Republic of China, Kagoshima University, 1-21-24 Kohrimoto, Kagoshima 890, Japan, and Department of Pharmacology, Tohoku College of Pharmacy, 4-4-1 Komatsushima, Aoba-ku, Sendai 981, Japan