High resolution autoradiographic determination of the topographic distribution of radioactivity in the hippocampal formation after injection of [1-14C]glucose or 2-deoxy[14C]glucose.

Using high resolution autoradiography, the accumulation of radioactivity after intravenous injection of [1-14C]glucose was measured in the corpus callosum, hippocampus, dorsal hippocampal commissure, somatosensory cortex, inferior colliculus and pontine periaqueductal grey. Autoradiograms were prepared by thaw-mounting 4 micron frozen sections on nuclear emulsion-coated slides, and were evaluated quantitatively with a computer-assisted video system for automated counting of silver grains. In all brain regions examined, silver grain densities were greater in rats killed 30 min after injection of [1-14C]glucose compared to rats killed 10 min after injection. After intravenous injection of [1-14C]glucose or 2-deoxy[14C]glucose, the relative uptake and retention of radioactivity in different hippocampal subregions was compared. Striking differences were found in the hippocampus between 2-deoxy[14C]glucose and [1-14C]glucose autoradiograms. After injection of 2-deoxy[14C]glucose, there were large variations in the uptake and retention of radioactivity among different pyramidal cell fields. The CA 3 pyramidal cell field retained considerably more radioactivity than other pyramidal cell fields after injection of 2-deoxy[14C]glucose, while after injection of [1-14C]glucose, the retention of radioactivity was similar in all pyramidal cell fields. After [1-14C]glucose injection, the dentate gyrus contained relatively high levels of radioactivity and more 14C accumulated in the granular layer, compared to the molecular layer. In contrast, after 2-deoxy[14C]glucose injection, there was uniformly less radioactivity throughout the dentate gyrus when compared to rats injected with [1-14C]glucose and there was no preferential accumulation of 2-deoxy[14C]glucose in the granular layer compared to the molecular layer.(ABSTRACT TRUNCATED AT 250 WORDS)