1. Department of Neurology, Institute of Clinical Medicine, University of Tsukuba, Tsukuba, 305, Japan.
2. Department of Biochemistry, Institute of Basic Medical Sciences, University of Tsukuba, Tsukuba, 305, Japan.
3. Department of Histochemistry, Royal Postgraduate Medical School, London W12 ONN, United Kingdom.
4. Department of Pharmacology, Institute of Basic Medical Sciences, University of Tsukuba, Tsukuba, 305, Japan.
5. Department of Anatomy, Institute of Basic Medical Sciences, University of Tsukuba, Tsukuba, 305, Japan.