title: Hippocampal neurons recycle BDNF for activity-dependent secretion and LTP maintenance.
abstract: Regulation of brain-derived neurotrophic factor (BDNF) secretion plays a critical role in long-term potentiation (LTP). It is generally thought that the supply for this secretion is newly synthesized BDNF targeted to the synapse. Here we provide evidence that hippocampal neurons additionally recycle BDNF for activity-dependent secretion. Exogenously applied BDNF is internalized by cultured neurons and rapidly becomes available for activity-dependent secretion, which is controlled by the same mechanisms that regulate the secretion of newly synthesized BDNF. Moreover, BDNF recycling replaced the new synthesis pathway in mediating the maintenance of LTP in hippocampal slices: the late phase LTP, which is abolished by protein synthesis inhibition, was rescued in slices preincubated with BDNF. Thus, endocytosed BDNF is fed back to the activity-dependent releasable pool required for LTP maintenance.
authors.affiliation: CNR-ITOI/ISMN, Bologna, Italy.
authors.forename: Spartaco
authors.initials: S
authors.lastname: Santi
authors.forename: Silvia
authors.initials: S
authors.lastname: Cappello
authors.forename: Massimo
authors.initials: M
authors.lastname: Riccio
authors.forename: Matteo
authors.initials: M
authors.lastname: Bergami
authors.forename: Giorgio
authors.initials: G
authors.lastname: Aicardi
authors.forename: Ursula
authors.initials: U
authors.lastname: Schenk
authors.forename: Michela
authors.initials: M
authors.lastname: Matteoli
authors.forename: Marco
authors.initials: M
authors.lastname: Canossa
mesh_terms: D000818:Animals; D000841:Anisomycin / Q000494:pharmacology; D019208:Brain-Derived Neurotrophic Factor / Q000378:metabolism* / Q000494:pharmacology; D002478:Cells, Cultured; D004705:Endocytosis; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism*; D066298:In Vitro Techniques; D017774:Long-Term Potentiation / Q000187:drug effects / Q000502:physiology*; D008297:Male; D008854:Microscopy, Electron; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D020813:Receptor, trkB / Q000378:metabolism
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D011500:Protein Synthesis Inhibitors; D000841:Anisomycin; D020813:Receptor, trkB