Postsynaptic expression of a new calcium pathway in hippocampal CA3 neurons and its influence on mossy fiber long-term potentiation.
Wataru Kakegawa,Nobuaki Yamada,Masae Iino,Kimihiko Kameyama,Tatsuya Umeda,Keisuke Tsuzuki,Seiji Ozawa +6 more
TLDR
Whether Ca2+ influx through the newly produced postsynaptic receptors during high-frequency stimulation affects the induction of MF LTP is examined, and results supported the notion that MF L TP is independent of post Synaptic Ca2+.Abstract:
Long-term potentiation (LTP) in the CA1 region of the hippocampus is induced by postsynaptic Ca2+ influx via NMDA receptors (NMDARs). However, this synaptic plasticity occurs independently of NMDARs when Ca2+-permeable AMPA receptors (AMPARs) are expressed at postsynaptic sites using various genetic techniques, indicating that an increase in Ca2+ 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 Ca2+ influx through the newly produced postsynaptic receptors during high-frequency stimulation affects the induction of MF LTP. For this purpose, we expressed Ca2+-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 Ca2+ 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 Ca2+-impermeable AMPARs at MF synapses were converted into Ca2+-permeable receptors by GluR2Q expression. However, the postsynaptic expression of Ca2+-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 Ca2+.read more
Citations
More filters
Journal ArticleDOI
Synaptic plasticity at hippocampal mossy fibre synapses
Roger A. Nicoll,Dietmar Schmitz +1 more
TL;DR: Recent work from several laboratories on the various forms of synaptic plasticity at hippocampal mossy fibre synapses conclude that these contacts have just begun to reveal their many secrets.
Journal ArticleDOI
A Learning and Memory Area in the Octopus Brain Manifests a Vertebrate-Like Long-Term Potentiation
TL;DR: Findings suggest that convergent evolution has led to the selection of similar activity-dependent synaptic processes that mediate complex forms of learning and memory in vertebrates and invertebrates.
Journal ArticleDOI
Calcium-permeable AMPA receptors appear in cortical neurons after traumatic mechanical injury and contribute to neuronal fate.
TL;DR: An in vitro model of TBI is used to show a gradual appearance of CP-AMPARs four hours following injury to cortical neurons, and the appearance is mediated by the phosphorylation of CaMKIIalpha following injury, pointing to a potentially new and more targeted therapeutic approach for treating TBI.
Journal ArticleDOI
Isoform‐specific distribution of the plasma membrane Ca2+ ATPase in the rat brain
TL;DR: Investigation of the distribution of each of the four PMCA isoforms in the rat brain shows that each isoform is independently organized and suggests that PMCAs may play a more complex role in calcium homeostasis than generally recognized.
Journal ArticleDOI
Input- and subunit-specific AMPA receptor trafficking underlying long-term potentiation at hippocampal CA3 synapses.
TL;DR: MF and AF postsynaptic sites possess distinct properties for AMPAR trafficking in CA3 pyramidal neurons, as indicated by the results of this study.
References
More filters
Journal ArticleDOI
A synaptic model of memory: long-term potentiation in the hippocampus
TL;DR: The best understood form of long-term potentiation is induced by the activation of the N-methyl-d-aspartate receptor complex, which allows electrical events at the postsynaptic membrane to be transduced into chemical signals which, in turn, are thought to activate both pre- and post Synaptic mechanisms to generate a persistent increase in synaptic strength.
Journal ArticleDOI
Cloned Glutamate Receptors
TL;DR: The application of molecular cloning technology to the study of the glutamate receptor system has led to an explosion of knowledge about the structure, expression, and function of this most important fast excitatory transmitter system in the mammalian brain.
Journal ArticleDOI
The effect of sodium ions on the electrical activity of the giant axon of the squid
A. L. Hodgkin,B. Katz +1 more
Journal ArticleDOI
A simple method for organotypic cultures of nervous tissue
TL;DR: Hippocampal slices prepared from 2-23-day-old neonates were maintained in culture at the interface between air and a culture medium and yielded thin slices which remain 1-4 cell layers thick and are characterized by a well preserved organotypic organization.
Journal ArticleDOI
Optimized survival of hippocampal neurons in B27-supplemented Neurobasal, a new serum-free medium combination
TL;DR: High survival was achieved with osmolarity lower than found in Dulbecco's Modified Eagle's Medium (DMEM), and by reducing cysteine and glutamine concentrations and by the elimination of toxic ferrnous sulphate found in DME/F12, and Neurobasal is a new medium that incorporates modifications to DMEM.