1. Institute for Biomedical Research, Suntory Ltd., 1-1-1, Wakayamadai, Shimamoto-cho, Mishima-gun, Osaka 618, Japan, Department of Pharmacology and Medical Computation Center, Osaka Medical College, 2-7 Daigaku-cho, Takatsuki 569, Japan, Department of Pharmacology, Shimane Medical University, 89-1 Enya-cho, Izumo, Shimane 693, Japan, and Department of Internal Medicine, School of Medicine, Fukuoka University, 7-45-1, Nanakuma, Jonan-ku, Fukuoka 814-01, Japan