1. From the Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts (M.S., E.M., H.-s.S., F.I.); Department of Chemistry, Washington State University, Pullman, Washington (W.C., M.X.); and Graduate School of Pharmaceutical Sciences, University of Tokyo, Bunkyo-ku, Tokyo, Japan (K.H.).