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Heterogeneity of synaptic plasticity at unitary CA3-CA1 and CA3-CA3 connections in rat hippocampal slice cultures.
| Content Provider | Semantic Scholar |
|---|---|
| Author | Debanne, Dominique Gähwiler, Beat H. Thompson, Scott M. |
| Copyright Year | 1999 |
| Abstract | Long-term potentiation (LTP) of unitary EPSPs, generated by pairs of monosynaptically connected CA3 and CA1 pyramidal cells, was compared with LTP of extracellularly evoked, multi-unitary EPSPs in rat hippocampal slice cultures. LTP was induced by repeated, synchronous pairing of low-frequency presynaptic and postsynaptic activity. Three differences were observed. First, LTP of multi-unitary EPSPs displayed two phases: transient (<5 min) and sustained. Potentiation of unitary EPSPs displayed both phases in 42% of experiments; the remainder showed sustained potentiation only. Unitary EPSPs displaying transient-sustained and only sustained potentiation could be recorded from single postsynaptic cells, indicating that excitatory synapses on a given cell are heterogeneous with respect to short-term plasticity. Second, whereas LTP of multi-unitary EPSPs never resulted in greater than twofold increases in amplitude (mean potentiation of 175% of control), maximal LTP of unitary EPSPs was as great as 13-fold (mean potentiation of 250%). Third, LTP could not be induced in 24% of unitary EPSPs. We provide here the first evidence for the coexistence of potentiatable and nonpotentiatable synapses on individual postsynaptic neurons. Thirty-seven percent of connections not displaying LTP exhibited long-term depression (LTD), suggesting that the connections were already maximally potentiated. In the remaining 63% of these pairs, neither LTP nor LTD could be induced, despite the existence of a pharmacologically identified, NMDA receptor-mediated EPSP component. In conclusion, there is considerable heterogeneity in the amplitude and time course of LTP expression at different synaptic connections. A substantial proportion of apparently nonplastic synapses probably accounts for the weaker potentiation displayed by compound EPSPs. |
| File Format | PDF HTM / HTML |
| DOI | 10.1523/JNEUROSCI.19-24-10664.1999 |
| Alternate Webpage(s) | http://www.jneurosci.org/content/jneuro/19/24/10664.full.pdf |
| PubMed reference number | 10594050 |
| Alternate Webpage(s) | https://doi.org/10.1523/JNEUROSCI.19-24-10664.1999 |
| Journal | Medline |
| Volume Number | 19 |
| Issue Number | 24 |
| Journal | The Journal of neuroscience : the official journal of the Society for Neuroscience |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
