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Postsynaptic expression of a new calcium pathway in hippocampal CA3 neurons and its influence on mossy fiber long-term potentiation.
| Content Provider | Semantic Scholar |
|---|---|
| Author | Kakegawa, Wataru Yamada, Nobuaki Iino, Masae Kameyama, Kimihiko Umeda, Tatsuya Tsuzuki, Keisuke Ozawa, Seiji |
| Copyright Year | 2002 |
| Abstract | Long-term potentiation (LTP) in the CA1 region of the hippocampus is induced by postsynaptic Ca(2+) influx via NMDA receptors (NMDARs). However, this synaptic plasticity occurs independently of NMDARs when Ca(2+)-permeable AMPA receptors (AMPARs) are expressed at postsynaptic sites using various genetic techniques, indicating that an increase in Ca(2+) level at critical postsynaptic sites, regardless of its entry pathway, triggers the induction of LTP at CA1 synapses. In contrast, NMDARs are sparsely distributed on mossy fiber (MF) synapses in CA3 hippocampal neurons, and most evidence favors the presynaptic mechanism for LTP induction, although some reports suggested a postsynaptic mechanism. In this study, we examined whether Ca(2+) influx through the newly produced postsynaptic receptors during high-frequency stimulation affects the induction of MF LTP. For this purpose, we expressed Ca(2+)-permeable AMPARs in CA3 pyramidal neurons by Sindbis viral-mediated gene transfer of the unedited form of the glutamate receptor 2 (GluR2Q) subunit, as a new pathway for postsynaptic Ca(2+) entry, in rat hippocampal organotypic cultures. Virally expressed myc-tagged GluR2Q was detected at the complex spines known as the thorny excrescences, which serve as postsynaptic targets for MF synaptic input, on the proximal apical dendrites of CA3 pyramidal cells. Furthermore, endogenous Ca(2+)-impermeable AMPARs at MF synapses were converted into Ca(2+)-permeable receptors by GluR2Q expression. However, the postsynaptic expression of Ca(2+)-permeable AMPARs had no significant influence on the two types of MF LTP induced by different stimulus protocols. These results supported the notion that MF LTP is independent of postsynaptic Ca(2+). |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://www.jneurosci.org/content/22/11/4312.full.pdf |
| PubMed reference number | 12040036v1 |
| Volume Number | 22 |
| Issue Number | 11 |
| Journal | The Journal of neuroscience : the official journal of the Society for Neuroscience |
| Language | English |
| Access Restriction | Open |
| Subject Keyword | AMPA Receptors CA1 field CA3 field Calcium Dendrites Gene Transfer Glutamate Receptor Glutamic Acid Hereditary Diseases Hippocampus (Brain) Long-Term Potentiation N-Methyl-D-Aspartate Receptors N-Methylaspartate Neuronal Plasticity Precipitating Factors Protocols documentation Pyramidal Cells Synapses Tissue fiber Tracer Vertebral column chemosensitization/potentiation mossy fiber |
| Content Type | Text |
| Resource Type | Article |
