Cerebral metabolic mapping at the cellular level with dry-mount autoradiography of [3H]2-deoxyglucose

The uptake and retention of radioactivity from [3H]2-deoxyglucose [( 3H]2-DG) was assessed in certain regions of the rat brain under basal conditions using dry-mount autoradiography, a procedure which affords the best available conditions to accurately localize diffusable radiolabeled compounds at cellular and subcellular levels. The overall amount of radioactivity accumulated in neuropil and in neuronal cell bodies was similar in most brain regions examined. Of the regions assessed, the CA3 pyramidal cell field of the hippocampus was the only region in which the radioactivity in cell bodies was notably greater than that of neuropil. In the somatosensory cortex and in the lateral hypothalamus, a wide range of radioactivity was found among individual neurons and among different areas of neuropil. In all brain regions examined, a subpopulation of small cells, with morphological characteristics of glial cells, accumulated [3H]2-DG to a much greater extent than other glial cells or neurons. That finding suggests that certain glial cells are in a markedly higher metabolic state than other brain cells.