title: Synaptic tagging and capture: differential role of distinct calcium/calmodulin kinases in protein synthesis-dependent long-term potentiation.
abstract: Weakly tetanized synapses in area CA1 of the hippocampus that ordinarily display long-term potentiation lasting approximately 3 h (called early-LTP) will maintain a longer-lasting change in efficacy (late-LTP) if the weak tetanization occurs shortly before or after strong tetanization of an independent, but convergent, set of synapses in CA1. The synaptic tagging and capture hypothesis explains this heterosynaptic influence on persistence in terms of a distinction between local mechanisms of synaptic tagging and cell-wide mechanisms responsible for the synthesis, distribution, and capture of plasticity-related proteins (PRPs). We now present evidence that distinct CaM kinase (CaMK) pathways serve a dissociable role in these mechanisms. Using a hippocampal brain-slice preparation that permits stable long-term recordings in vitro for >10 h and using hippocampal cultures to validate the differential drug effects on distinct CaMK pathways, we show that tag setting is blocked by the CaMK inhibitor KN-93 (2-[N-(2-hydroxyethyl)]-N-(4-methoxybenzenesulfonyl)amino-N-(4-chlorocinnamyl)-N-methylbenzylamine) that, at low concentration, is more selective for CaMKII. In contrast, the CaMK kinase inhibitor STO-609 [7H-benzimidazo(2,1-a)benz(de)isoquinoline-7-one-3-carboxylic acid] specifically limits the synthesis and/or availability of PRPs. Analytically powerful three-pathway protocols using sequential strong and weak tetanization in varying orders and test stimulation over long periods of time after LTP induction enable a pharmacological dissociation of these distinct roles of the CaMK pathways in late-LTP and so provide a novel framework for the molecular mechanisms by which synaptic potentiation, and possibly memories, become stabilized.
authors.affiliation: Centre for Cognitive and Neural Systems, University of Edinburgh, EH8 9JZ, Edinburgh, United Kingdom.
authors.forename: Roger L
authors.initials: RL
authors.lastname: Redondo
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Okuno
authors.forename: Patrick A
authors.initials: PA
authors.lastname: Spooner
authors.forename: Bruno G
authors.initials: BG
authors.lastname: Frenguelli
authors.forename: Haruhiko
authors.initials: H
authors.lastname: Bito
authors.forename: Richard G M
authors.initials: RG
authors.lastname: Morris
mesh_terms: D000818:Animals; D001562:Benzimidazoles / Q000494:pharmacology; D001596:Benzylamines / Q000494:pharmacology; D054729:Calcium-Calmodulin-Dependent Protein Kinase Type 1 / Q000096:biosynthesis / Q000737:chemistry / Q000502:physiology*; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2 / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000737:chemistry / Q000502:physiology*; D002478:Cells, Cultured; D017774:Long-Term Potentiation / Q000187:drug effects / Q000502:physiology*; D008297:Male; D053644:Naphthalimides / Q000494:pharmacology; D009473:Neuronal Plasticity / Q000187:drug effects / Q000502:physiology; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D013449:Sulfonamides / Q000494:pharmacology; D013569:Synapses / Q000187:drug effects / Q000201:enzymology*; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology*; D000096926:Benzenesulfonamides
chemical_list: D001562:Benzimidazoles; D001596:Benzylamines; D054729:Calcium-Calmodulin-Dependent Protein Kinase Type 1; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D053644:Naphthalimides; D047428:Protein Kinase Inhibitors; D013449:Sulfonamides; C458525:STO 609; C072105:KN 93; D000096926:Benzenesulfonamides