TY - JOUR
T1 - Age dependence of homosynaptic non-NMDA mediated long-term depression in field CA1 of rat hippocampal slices
AU - Velíšek, Libor
AU - Moshé, Solomon L.
AU - Stanton, Patric K.
N1 - Funding Information:
Acknowledgements. This work was supportedb y an American Epilepsy Society fellowshipw ith supportf rom the Milken Family Medical Foundatkmto L.V., NIH Grant NS20253 to S.L.M., and NIH Grant MH45752 and an Office of Naval Researchg rant to P.K.S.
PY - 1993/10/15
Y1 - 1993/10/15
N2 - It has been hypothesized that high levels of presynaptic activity that fail to activate postsynaptic N-methyl-d-aspartate (NMDA) receptors may lead to long-term depression (LTD). Therefore, we tested the ability of high-frequency (50 Hz) synaptic stimulation in the presence of a blocker of NMDA receptors to elicit homosynaptic LTD at Schaffer collateral-CA1 synapses in hippocampal slices from 15-, 30- and 60-day-old rats. In control slices, there were no developmental differences in the incidence of long-term potentiation (LTP) of either EPSP slope or population spike amplitude. However, while NMDA receptor blockade with the specific antagonist d-2-amino-5-phosphonopentanoic acid (AP5; 25 μM) completely eliminated LTP in 30 and 60-day-olds, a significant number of slices from 15-day-old rats displayed some non-NMDA LTP of synaptic transmission. Moreover, under NMDA receptor blockade, the same high-frequency stimulation now induced homosynaptic LTD of population spike amplitude in a significant number of slices from 15- and 60-day-old rats (47% and 42%, respectively) but not in 30-day-olds (7%). LTD of population spike amplitude was most pronounced in 15-day-old slices (27 ± 6% of baseline), whereas, in 60-day-old slices, LTD was 81 ± 3% of baseline. LTD of EPSP slopes occurred in 44% of 15-day-olds, 13% of 30-day-olds, and 33% of slices from 60-day-old rats; the magnitude of EPSP was similar in 15 and 60-day-old slices (70 ± 9% versus 81 ± 1% of baseline). Our findings indicate that: (i) substantial non-NMDA LTD can be unmasked when NMDA receptors are blocked in slices from 15- and 60-day-old rats; (ii) during development, non-NMDA LTD is largest in the immature (15-day-old) hippocampus; and (iii) a part of LTP in 15-day-old slices is also independent of NMDA receptor activation.
AB - It has been hypothesized that high levels of presynaptic activity that fail to activate postsynaptic N-methyl-d-aspartate (NMDA) receptors may lead to long-term depression (LTD). Therefore, we tested the ability of high-frequency (50 Hz) synaptic stimulation in the presence of a blocker of NMDA receptors to elicit homosynaptic LTD at Schaffer collateral-CA1 synapses in hippocampal slices from 15-, 30- and 60-day-old rats. In control slices, there were no developmental differences in the incidence of long-term potentiation (LTP) of either EPSP slope or population spike amplitude. However, while NMDA receptor blockade with the specific antagonist d-2-amino-5-phosphonopentanoic acid (AP5; 25 μM) completely eliminated LTP in 30 and 60-day-olds, a significant number of slices from 15-day-old rats displayed some non-NMDA LTP of synaptic transmission. Moreover, under NMDA receptor blockade, the same high-frequency stimulation now induced homosynaptic LTD of population spike amplitude in a significant number of slices from 15- and 60-day-old rats (47% and 42%, respectively) but not in 30-day-olds (7%). LTD of population spike amplitude was most pronounced in 15-day-old slices (27 ± 6% of baseline), whereas, in 60-day-old slices, LTD was 81 ± 3% of baseline. LTD of EPSP slopes occurred in 44% of 15-day-olds, 13% of 30-day-olds, and 33% of slices from 60-day-old rats; the magnitude of EPSP was similar in 15 and 60-day-old slices (70 ± 9% versus 81 ± 1% of baseline). Our findings indicate that: (i) substantial non-NMDA LTD can be unmasked when NMDA receptors are blocked in slices from 15- and 60-day-old rats; (ii) during development, non-NMDA LTD is largest in the immature (15-day-old) hippocampus; and (iii) a part of LTP in 15-day-old slices is also independent of NMDA receptor activation.
KW - 2-Amino-5-phosphonopentanoic acid
KW - Development
KW - Hippocampus
KW - Long-term depression
KW - Long-term potentiation
KW - N-Methyl-d-aspartate
KW - Ontogeny
KW - Synaptic plasticity
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UR - http://www.scopus.com/inward/citedby.url?scp=0027360012&partnerID=8YFLogxK
U2 - 10.1016/0165-3806(93)90029-A
DO - 10.1016/0165-3806(93)90029-A
M3 - Article
C2 - 7903226
AN - SCOPUS:0027360012
SN - 0165-3806
VL - 75
SP - 253
EP - 260
JO - Developmental Brain Research
JF - Developmental Brain Research
IS - 2
ER -