In:
Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 95, No. 14 ( 1998-07-07), p. 8310-8315
Abstract:
During a critical period of postnatal development, between postnatal days 6 and 14, a high-frequency stimulation train (100 Hz for 1 s) to the mossy fibers induces a long-term depression (LTD) of synaptic efficacy of 29 ± 5.2%. This form of LTD is homosynaptic. It is independent of the activation of N -methyl- d -aspartate or metabotropic glutamate receptors but needs an increase in calcium into the postsynaptic cell for its induction. At the same synapse LTD also could be induced by low-frequency stimulation of the mossy fibers (1 Hz for 15 min). In this case the magnitude of the depression is 37 ± 4.2%. This form of LTD is N -methyl- d -aspartate independent but requires the activation of metabotropic glutamate receptors because it is prevented by (S)-α-methyl-4-carboxyphenylglycine (1 mM). Moreover its induction appears to be presynaptic, because, in contrast with the high-frequency one, it is not blocked by loading the postsynaptic cell with the calcium chelator EGTA or bis-(- o -aminophenoxy)ethane- N , N , N ′, N ′-tetraacetic acid (BAPTA). Saturation of one form of LTD does not occlude the other, suggesting that high and low frequency-induced LTD depend on distinct mechanisms of induction and expression. Quantal (noise deconvolution) analysis of minimal excitatory postsynaptic potentials shows, similarly to high-frequency LTD, a decrease in quantal content without any change in quantal size after low-frequency LTD, suggesting that in both forms of LTD the site where maintenance mechanisms are located is presynaptic.
Type of Medium:
Online Resource
ISSN:
0027-8424
,
1091-6490
DOI:
10.1073/pnas.95.14.8310
Language:
English
Publisher:
Proceedings of the National Academy of Sciences
Publication Date:
1998
detail.hit.zdb_id:
209104-5
detail.hit.zdb_id:
1461794-8
SSG:
11
SSG:
12
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