title: Homonuclear 1H double-resonance difference spectroscopy of the rat brain in vivo.
abstract: We have used 1H homonuclear double-resonance difference spectroscopy at 360.13 MHz to resolve specific metabolite resonances in the brains of intact rats. Metabolite resonances resolved include previously obscured proton resonances of alanine, gamma-aminobutyric acid (GABA), glutamate, and taurine. The gamma-aminobutyric acid alpha- and gamma-CH2 proton resonances were observed in the living rat in the difference spectrum obtained upon irradiation of the beta-CH2 proton resonance at 1.91 ppm. A 3-fold increase in the intensity of the alpha- and gamma-CH2 resonances of gamma-aminobutyric acid was observed 30 min after death. The alpha-CH and gamma-CH2 resonances of glutamate were also resolved in vivo by selective irradiation of the beta-CH2 protons to which they are spin-coupled. In addition, this technique was used to observe the beta-CH3 protons of lactate through the intact scalp of a rat. Large lipid signals arising from scalp tissue were eliminated in the difference spectrum, revealing the lactate beta-CH3 resonance.
mesh_terms: D000409:Alanine / Q000378:metabolism; D000818:Animals; D001921:Brain / Q000000981:diagnostic imaging* / Q000378:metabolism; D005971:Glutamates / Q000378:metabolism; D018698:Glutamic Acid; D007773:Lactates / Q000378:metabolism; D019344:Lactic Acid; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D011180:Postmortem Changes; D011859:Radiography; D051381:Rats; D013654:Taurine / Q000378:metabolism; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
chemical_list: D005971:Glutamates; D007773:Lactates; D013654:Taurine; D019344:Lactic Acid; D018698:Glutamic Acid; D005680:gamma-Aminobutyric Acid; D000409:Alanine