Habituation of monosynaptic field potentials in the dentate gyrus of freely moving rats interferes with LTP.
In 30 male Wistar rats, monosynaptically evoked field potentials in the dentate gyrus were registered under different conditions of repetitive stimulation and the long-term changes in synaptic transmission studied. Low-frequency stimulation induces a habituation-like decrement of the field-EPSP, but not of the population spike which interferes with the maintenance of LTP when administered after tetanic stimulation. The habituation-like response decrement, however, does not influence paired pulse-depression seen with an interstimulus interval of 20.0 ms. The paired pulse-plasticity, on the other hand, can be influenced by the tetanic stimulation (diminution of facilitation or depression), being dependent on the intensity of test stimuli. The results can be interpreted in terms of a complex influence of low-frequency- and tetanic stimulation on the elements of the dentate local circuitry and point to the necessity of considering long-term plastic changes in the investigation of substance- or stimulation-induced deviations of neuronal responses.
Krug
M
M
Institute of Pharmacology and Toxicology, Medical Academy, Magdeburg, G.D.R.
Wagner
M
M
Brödemann
R
R
Matthies
H
H
D000200:Action Potentials; D000818:Animals; D004558:Electric Stimulation; D006185:Habituation, Psychophysiologic / Q000502:physiology*; D006624:Hippocampus / Q000502:physiology*; D008297:Male; D009473:Neuronal Plasticity; D051381:Rats; D011919:Rats, Inbred Strains; D013569:Synapses / Q000502:physiology*