1. Department of Pharmacology, Yonsei University College of Medicine, Seoul 120-752, Korea.
2. Division of Metabolic Disease, Department of Biomedical Science, National Institutes of Health, Osong 363-951, Korea.
3. Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul 120-752, Korea.
4. Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul 120-752, Korea.