Stable mossy fiber long-term potentiation requires calcium influx at the granule cell soma, protein synthesis, and microtubule-dependent axonal transport.
J Neurosci
; 30(39): 12996-3004, 2010 Sep 29.
Article
em En
| MEDLINE
| ID: mdl-20881117
ABSTRACT
The synapses formed by the mossy fiber (MF) axons of hippocampal dentate gyrus granule neurons onto CA3 pyramidal neurons exhibit an intriguing form of experience-dependent synaptic plasticity that is induced and expressed presynaptically. In contrast to most other CNS synapses, long-term potentiation (LTP) at the MF-CA3 synapse is readily induced even during blockade of postsynaptic glutamate receptors. Furthermore, blocking voltage-gated Ca(2+) channels prevents MF-LTP, supporting an involvement of presynaptic Ca(2+) signaling via voltage-gated Ca(2+) channels in MF-LTP induction. We examined the contribution of activity in both dentate granule cell somata and MF terminals to MF-LTP. We found that the induction of stable MF-LTP requires tetanization-induced action potentials not only at MF boutons, but also at dentate granule cell somata. Similarly, blocking Ca(2+) influx via voltage-gated Ca(2+) channels only at the granule cell soma was sufficient to disrupt MF-LTP. Finally, blocking protein synthesis or blocking fast axonal transport mechanisms via disruption of axonal tubulin filaments resulted in decremental MF-LTP. Collectively, these data suggest that-in addition to Ca(2+) influx at the MF terminals-induction of MF synaptic plasticity requires action potential-dependent Ca(2+) signaling at granule cell somata, protein synthesis, and fast axonal transport along MFs. A parsimonious interpretation of these results is that somatic activity triggers protein synthesis at the soma; newly synthesized proteins are then transported to MF terminals, where they contribute to the stabilization of MF-LTP. Finally, the present data imply that synaptic plasticity at the MF-CA3 synapse can be affected by local modulation of somatic and presynaptic Ca(2+) channel activity.
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Base de dados:
MEDLINE
Assunto principal:
Transporte Axonal
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Cálcio
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Potenciação de Longa Duração
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Giro Denteado
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Fibras Musgosas Hipocampais
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Região CA3 Hipocampal
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Microtúbulos
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Proteínas do Tecido Nervoso
Limite:
Animals
Idioma:
En
Ano de publicação:
2010
Tipo de documento:
Article