1. Department of Pharmacology, Nagoya University School of Medicine, Tsurumai 65, Showa-ku, Nagoya 466, Japan
2. Department of Anatomy, Nagoya University School of Medicine, Tsurumai 65, Showa-ku, Nagoya 466, Japan
3. Department of Biochemistry, Institute for Brain Research, Faculty of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113, Japan