Localized 15N NMR spectroscopy of rat brain by ISIS.
Three-dimensional image-selected in vivo spectroscopy (ISIS), combined with proton-decoupled nuclear-Overhauser-enhanced 15N nuclear magnetic resonance (NMR), was used to localize [15N]metabolites, observed by a head coil, to the brain in rats. In spontaneously breathing anesthetized rats given intravenous [15N]ammonium acetate infusion, brain [5-15N]glutamine was observed in the localized spectrum with a v1/2 of 5 Hz in 19-28 min at 4.7 T, while the signal from blood [15N]urea was eliminated by the localization process. In rats given [15N]leucine infusion, the peak representing predominantly (89%) brain [15N]glutamate was observed, with elimination of the signal from muscle [15N]alanine. In vivo peak areas of the brain [15N]metabolites in the localized spectra were proportional to their concentrations. The advantages and limitations of localization by ISIS using a volume coil with a homogeneous B1 field are compared with those of localization by a surface coil for in vivo 15N NMR study of neurotransmitters in the brain.
Kanamori
K
K
Magnetic Resonance Spectroscopy Laboratory, Huntington Medical Research Institutes, Pasadena, California 91105, USA.
Ross
B D
BD
D000085:Acetates / Q000008:administration & dosage; D000818:Animals; D001921:Brain / Q000033:anatomy & histology*; D001931:Brain Mapping / Q000379:methods; D004195:Disease Models, Animal; D005973:Glutamine / Q000378:metabolism*; D007089:Image Enhancement / Q000379:methods; D009682:Magnetic Resonance Spectroscopy / Q000295:instrumentation / Q000379:methods*; D008297:Male; D009590:Nitrogen Radioisotopes; D019047:Phantoms, Imaging; D051381:Rats; D017208:Rats, Wistar; D012680:Sensitivity and Specificity
D000085:Acetates; D009590:Nitrogen Radioisotopes; D005973:Glutamine; C018824:ammonium acetate