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Long‐term Potentiation of NMDA Receptor‐mediated EPSP in Guinea‐pig Hippocampal Slices
Author(s) -
Berretta N.,
Berton F.,
Bianchi R.,
Brunelli M.,
Capogna M.,
Francesconi W.
Publication year - 1991
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/j.1460-9568.1991.tb00096.x
Subject(s) - excitatory postsynaptic potential , long term potentiation , cnqx , nmda receptor , neuroscience , schaffer collateral , chemistry , post tetanic potentiation , tetanic stimulation , ampa receptor , biology , receptor , inhibitory postsynaptic potential , biochemistry
Hippocampal slices from guinea‐pigs were used to examine the long‐term potentiation (LTP) of the N ‐methyl‐D‐aspartate (NMDA)‐mediated excitatory postsynaptic potential (EPSP). lntracellular recordings were performed from CA1 pyramidal neurons in the presence of 6‐cyano‐7‐nitroquinoxaline‐2,3‐dione (CNQX, 5–10 μM) and picrotoxin (50 μM). In these experimental conditions test stimuli applied at low frequency (0.1 Hz) to the Schaffer collateral ‐ commissural pathway evoked a prolonged EPSP (150–200 ms). To obtain this CNQX‐resistant EPSP, stimulus intensities had to be raised above the level required to evoke an EPSP of comparable amplitude in physiological solution. Tetanic stimulation (two trains of 100 Hz, 1 s every 20 s) led to a potentiation of the CNQX‐resistant EPSP, and this potentiated response was abolished with d ‐(‐)‐2‐amino‐5‐phosphonovaleric acid (50μM). The potentiation of the NMDA receptor‐mediated EPSP was more pronounced for strong than for weak test stimuli, and was suppressed when test EPSPs were evoked during membrane hyperpolarization. These results suggest that NMDA receptor‐mediated responses can undergo LTP, and hence can contribute to the maintenance of LTP.