1. Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu 610041, PR China
2. University of Chinese Academy of Sciences, Beijing 100049, PR China
3. Southwest Minzu University, Chengdu 610041, P. R. China
4. Laboratory of Anaesthesia & Critical Care Medicine, Translational Neuroscience Center and Department of Anaesthesiology, West China Hospital, Sichuan University, Chengdu 610041, P. R. China