title: Brain-derived neurotrophic factor induces long-term potentiation in intact adult hippocampus: requirement for ERK activation coupled to CREB and upregulation of Arc synthesis.
abstract: Brain-derived neurotrophic factor (BDNF) is implicated in long-term synaptic plasticity in the adult hippocampus, but the cellular mechanisms are little understood. Here we used intrahippocampal microinfusion of BDNF to trigger long-term potentiation (BDNF-LTP) at medial perforant path--granule cell synapses in vivo. BDNF infusion led to rapid phosphorylation of the mitogen-activated protein (MAP) kinases ERK (extracellular signal-regulated protein kinase) and p38 but not JNK (c-Jun N-terminal protein kinase). These effects were restricted to the infused dentate gyrus; no changes were observed in microdissected CA3 and CA1 regions. Local infusion of MEK (MAP kinase kinase) inhibitors (PD98059 and U0126) during BDNF delivery abolished BDNF-LTP and the associated ERK activation. Application of MEK inhibitor during established BDNF-LTP had no effect. Activation of MEK-ERK is therefore required for the induction, but not the maintenance, of BDNF-LTP. BDNF-LTP was further coupled to ERK-dependent phosphorylation of the transcription factor cAMP response element-binding protein. Finally, we investigated the expression of two immediate early genes, activity-regulated cytoskeleton-associated protein (Arc) and Zif268, both of which are required for generation of late, mRNA synthesis-dependent LTP. BDNF infusion resulted in selective upregulation of mRNA and protein for Arc. In situ hybridization showed that Arc transcripts are rapidly and extensively delivered to granule cell dendrites. U0126 blocked Arc upregulation in parallel with BDNF-LTP. The results support a model in which BDNF triggers long-lasting synaptic strengthening through MEK-ERK and selective induction of the dendritic mRNA species Arc.
authors.affiliation: Department of Physiology and Locus on Neuroscience, University of Bergen, N-5009 Bergen, Norway.
authors.forename: Shui-Wang
authors.initials: SW
authors.lastname: Ying
authors.forename: Marie
authors.initials: M
authors.lastname: Futter
authors.forename: Kobi
authors.initials: K
authors.lastname: Rosenblum
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Webber
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Hunt
authors.forename: Timothy V P
authors.initials: TV
authors.lastname: Bliss
authors.forename: Clive R
authors.initials: CR
authors.lastname: Bramham
mesh_terms: D000818:Animals; D019208:Brain-Derived Neurotrophic Factor / Q000494:pharmacology*; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism*; D003598:Cytoskeletal Proteins / Q000235:genetics / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006624:Hippocampus / Q000187:drug effects* / Q000502:physiology; D017403:In Situ Hybridization; D048031:JNK Mitogen-Activated Protein Kinases; D017774:Long-Term Potentiation / Q000187:drug effects* / Q000502:physiology; D008297:Male; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D015854:Up-Regulation / Q000187:drug effects / Q000502:physiology; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D017362:Cyclic AMP Response Element-Binding Protein; D003598:Cytoskeletal Proteins; D004791:Enzyme Inhibitors; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; C092069:activity regulated cytoskeletal-associated protein; D017346:Protein Serine-Threonine Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases