Peripheral sympathetic ingrowth can alter metabolic activity within the hippocampal formation.

After cholinergic denervation of the hippocampal formation, peripheral sympathetic fibers arising from the superior cervical ganglia grow into the dentate gyrus and CA3 region; the functional significance of sympathetic ingrowth into the hippocampal formation is unknown. Utilizing electrical stimulation of the preganglionic trunk in combination with 2-deoxy-D-[3H]-glucose fine-grained autoradiograms, we demonstrated an alteration of hippocampal glucose metabolism, suggesting that this neuronal rearrangement makes functional connections within the hippocampus.