title: Involvement of TrkB- and p75(NTR)-signaling pathways in two contrasting forms of long-lasting synaptic plasticity.
abstract: The repetition of experience is often necessary to establish long-lasting memory. However, the cellular mechanisms underlying this repetition-dependent consolidation of memory remain unclear. We previously observed in organotypic slice cultures of the rodent hippocampus that repeated inductions of long-term potentiation (LTP) led to a slowly developing long-lasting synaptic enhancement coupled with synaptogenesis. We also reported that repeated inductions of long-term depression (LTD) produced a long-lasting synaptic suppression coupled with synapse elimination. We proposed these phenomena as useful in vitro models for analyzing repetition-dependent consolidation. Here, we hypothesized that the enhancement and suppression are mediated by the brain-derived neurotrophic factor (BDNF)-TrkB signaling pathway and the proBDNF-p75(NTR) pathway, respectively. When we masked the respective pathways, reversals of the enhancement and suppression resulted. These results suggest the alternative activation of the p75(NTR) pathway by BDNF under TrkB-masking conditions and of the TrkB pathway by proBDNF under p75(NTR)-masking conditions, thus supporting the aforementioned hypothesis.
authors.affiliation: Department of Neuroscience, Osaka University Graduate School of Frontier Biosciences, Suita 565-0871 Osaka, Japan.
authors.forename: Shigeo
authors.initials: S
authors.lastname: Sakuragi
authors.forename: Keiko
authors.initials: K
authors.lastname: Tominaga-Yoshino
authors.forename: Akihiko
authors.initials: A
authors.lastname: Ogura
mesh_terms: D000818:Animals; D000906:Antibodies / Q000276:immunology; D019208:Brain-Derived Neurotrophic Factor / Q000378:metabolism; D005576:Colforsin / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects; D006624:Hippocampus / Q000378:metabolism; D066298:In Vitro Techniques; D017774:Long-Term Potentiation / Q000187:drug effects / Q000502:physiology*; D036881:Long-Term Synaptic Depression / Q000187:drug effects / Q000502:physiology*; D008734:Methoxyhydroxyphenylglycol / Q000031:analogs & derivatives / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D020813:Receptor, trkB / Q000276:immunology / Q000378:metabolism*; D017475:Receptors, Nerve Growth Factor / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D000906:Antibodies; D019208:Brain-Derived Neurotrophic Factor; D017475:Receptors, Nerve Growth Factor; C517634:Ngfr protein, mouse; D005576:Colforsin; D008734:Methoxyhydroxyphenylglycol; D020813:Receptor, trkB; C010117:3,4-dihydroxyphenylglycol