Time-dependent depotentiation in the dentate gyrus of freely moving rats by repeated brief 7 Hz stimulation.
Long-term potentiation (LTP) in the hippocampus of awake animals is known to be reversed by long trains of low-frequency stimulation (LFS). Here we show that a persistent LTP reversal, i.e. depotentiation (DP), can be induced in the dentate gyrus of freely moving rats by brief 7 Hz stimulations (three trains of 100 pulses, 1 min intertrain-interval) if LFS was applied 2 min after tetanization. In contrast, the same LFS protocol given 15 min after tetanization failed to induce long-lasting DP. Likewise, reduction of LFS (given 2 min post-tetanus) to two trains resulted only in short-term DP. Because naturally occurring hippocampal 7 Hz oscillatory events are correlated to new sensory input, our results might be relevant for the understanding of the mechanisms of LTP reversal induced by processing new information.
Straube
Thomas
T
Leibniz-Institute for Neurobiology, Department of Neurophysiology, Brenneckestrasse 6, D-39118, Magdeburg, Germany. straube@ifn-magdeburg.de
Frey
Julietta Uta
JU
D000818:Animals; D018891:Dentate Gyrus / Q000503:physiopathology*; D004558:Electric Stimulation; D017774:Long-Term Potentiation; D008297:Male; D051381:Rats; D017208:Rats, Wistar