THE MONOSIALOGANGLIOSIDE GM(1) DOSE-DEPENDENTLY REDUCES REGIONAL CEREBRAL METABOLIC RATES FOR GLUCOSE IN AWAKE RATS

Using the quantitative autoradiographic [C-14]2-deoxyglucose technique , regional cerebral metabolic rates for glucose (rCMRglc) were measure d in awake male Fischer-344 rats at 1, 2, 3, 4 and 6 h after administr ation of GM, 30 mg/kg and at 3 h after GM1 150 or 300 mg/kg. GM1 is a natural compound that is able to prevent neuron degeneration induced b y exposure to excitatory amino acids in vitro and by ischemia or neuro toxins in vivo. GM1 30 mg/kg, a dose very effective in preventing exci tatory amino acid-induced neurotoxicity, produced minimal rCMRglc chan ge over a 6 h period. GM1 150 and 300 mg/kg reduced rCMRglc, in 14 (31 %) and in 29 (64%) brain regions, respectively. Maximal metabolic effe cts occurred in hippocampal areas which possess, in specific subfields , the highest brain concentrations of different excitatory amino acid receptor subtypes. This finding suggests an effect by GM1 on postrecep tor mechanisms common to different excitatory amino acids.