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METAPLASTICITY Résumé de rapport

Project ID: 9092
Financé au titre de: FP6-MOBILITY
Pays: Germany

Final Activity Report Summary - METAPLASTICITY (Role of the Cav2.3 Voltage-gated Calcium Channel Subunit in Presynaptic Metaplasticity, and Hippocampal-dependent Learning and Memory)

Most Central nervous system (CNS) synapses exhibit a striking potential for activity-dependent changes in synaptic efficacy, occurring either as long-term depression or Long-term potentiation (LTP). Since these lasting changes in synaptic transmission are candidate mechanisms for learning and memory, considerable attention has focussed on their molecular mechanisms. At many CNS synapses, LTP induction appears to require postsynaptic activation of N-methyl-d-aspartate-type glutamate receptors. In contrast, LTP induction at the hippocampal Mossy fibre (MF)-CA3 synapse, as well as at a number of other synapses, is thought to rely mainly on presynaptic mechanisms (see Castillo, Weisskopf and Nicoll, 1994, Neuron, 12:261-9).

Previous work indicated that presynaptic Ca2+ influx is required for the induction of MF-LTP. However, the results of these earlier experiments did not allow for a determination of whether Ca2+ influx into the presynaptic neuron occurred at presynaptic versus somatic sites. We therefore developed a novel technique that allowed us to focally apply pharmacological agents to either the soma or the synapse of a neuron while recording MF field Excitatory postsynaptic potentials (fEPSPs).

Using this technique, we were able to assess the role of somatic versus synaptic activity in MF-LTP during LTP induction by temporarily inactivating the soma or the synapse. We found that somatic activity was necessary for the induction of stable MF-LTP.

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