Morphine brain pharmacokinetics at very low concentrations studied with Accelerator Mass Spectrometry and Liquid Chromatography-tandem Mass Spectrometry Muhammad Waqas Sadiq, Mehran Salehpour, Niklas Forsgard, Göran Possnert, Margareta Hammarlund-Udenaes Department of Pharmaceutical Biosciences, Uppsala University, Box 591, SE-75124 Uppsala, Sweden (M.W.S., M. H-U) Department of Physics and Astronomy, Ion Physics, Ångstrom Lab., Uppsala University, Box 534, SE-751 21 Uppsala, Sweden (M.S., N.F., G.P.) DMD Fast Forward. Published on November 8, 2010 as doi:10.1124/dmd.110.036434 Copyright 2010 by the American Society for Pharmacology and Experimental Therapeutics. This article has not been copyedited and formatted. The final version may differ from this version. DMD Fast Forward. Published on November 8, 2010 as DOI: 10.1124/dmd.110.036434 at ASPET Journals on July 19, 2022 dmd.aspetjournals.org Downloaded from