1. Biological/Pharmacological Laboratories, Central Pharmaceutical Research Institute, Japan Tobacco Inc., 1-1 Murasaki-cho, Takatsuki, Osaka 569-1125, Japan
2. Department of Agrobiology, Faculty of Agriculture, Niigata University, 2-8050 Igarashi, Nishiku, Niigata 950-2181, Japan
3. Laboratory of Animal Physiology and Functional Anatomy, Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan