1. State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu-Chong-Zhi Road, Zhangjiang Hi-Tech Park, Shanghai 201203, People's Republic of China, Department of Biology, Hainan Normal University, 99 South Long-Kun Road, Haikou 571158, People's Republic of China, and Department of Pharmacology, The Chinese University of Hong Kong, Hong Kong SAR, People's Republic of China