Regional [14C]palmitate incorporation into the hippocampus after transient cerebral ischemia in awake gerbils.

Incorporation of plasma [14C]palmitate into the hippocampus was measured using quantitative autoradiography and a ratio method of analysis between 10 min and 7 days after 5 min of bilateral occlusion of the common carotid arteries in awake gerbils. One day after carotid occlusion, relative palmitate incorporation was elevated by 16% and 20%, respectively (p less than 0.01), in the CA4 pyramidal cell layer and dentate gyrus of the hippocampus as compared with sham-operated animals. At 3 days, significant elevations of this magnitude were found in the CA3 and CA4 cell layers, and relative incorporation was reduced by 26% in the CA1 pyramidal cell layer. At 7 days, the only significant difference from control was a 15% elevated incorporation in the CA3 pyramidal cell layer. The results suggest that the turnover of palmitate-containing lipids is retained in the CA1 pyramidal layer of the gerbil hippocampus for 1 day and then reduced at 3 days after 5-min ischemia and that lipid synthesis is stimulated in hippocampal regions affected by but recovering from an ischemic insult (CA3, CA4, dentate gyrus).