title: Imaging Taurine in the Central Nervous System Using Chemically Specific X-ray Fluorescence Imaging at the Sulfur K-Edge.
abstract: A method to image taurine distributions within the central nervous system and other organs has long been sought. Since taurine is small and mobile, it cannot be chemically "tagged" and imaged using conventional immuno-histochemistry methods. Combining numerous indirect measurements, taurine is known to play critical roles in brain function during health and disease and is proposed to act as a neuro-osmolyte, neuro-modulator, and possibly a neuro-transmitter. Elucidation of taurine's neurochemical roles and importance would be substantially enhanced by a direct method to visualize alterations, due to physiological and pathological events in the brain, in the local concentration of taurine at or near cellular spatial resolution in vivo or in situ in tissue sections. We thus have developed chemically specific X-ray fluorescence imaging (XFI) at the sulfur K-edge to image the sulfonate group in taurine in situ in ex vivo tissue sections. To our knowledge, this represents the first undistorted imaging of taurine distribution in brain at 20 μm resolution. We report quantitative technique validation by imaging taurine in the cerebellum and hippocampus regions of the rat brain. Further, we apply the technique to image taurine loss from the vulnerable CA1 (cornus ammonis 1) sector of the rat hippocampus following global brain ischemia. The location-specific loss of taurine from CA1 but not CA3 neurons following ischemia reveals osmotic stress may be a key factor in delayed neurodegeneration after a cerebral ischemic insult and highlights the significant potential of chemically specific XFI to study the role of taurine in brain disease.
authors.affiliation: Molecular and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan , 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada.|Department of Chemistry, Curtin University , GPO Box U1987, Perth, Western Australia 6845, Australia.
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Hackett
authors.affiliation: College of Pharmacy and Nutrition, University of Saskatchewan , 107 Wiggins Road, Saskatoon, Saskatchewan S7N 5E5, Canada.
authors.forename: Phyllis G
authors.initials: PG
authors.lastname: Paterson
authors.affiliation: Molecular and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan , 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada.|Department of Chemistry, University of Saskatchewan , 110 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada.
authors.forename: Ingrid J
authors.initials: IJ
authors.lastname: Pickering
authors.affiliation: Molecular and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan , 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada.|Department of Chemistry, University of Saskatchewan , 110 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada.
authors.forename: Graham N
authors.initials: GN
authors.lastname: George
mesh_terms: D000818:Animals; D001921:Brain; D002490:Central Nervous System / Q000737:chemistry*; D005453:Fluorescence; D008297:Male; D061848:Optical Imaging / Q000379:methods*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013455:Sulfur / Q000737:chemistry*; D013654:Taurine / Q000032:analysis*; D014965:X-Rays
chemical_list: D013654:Taurine; D013455:Sulfur