title: Loose coupling between Ca2+ channels and release sensors at a plastic hippocampal synapse.
abstract: The distance between Ca(2+) channels and release sensors determines the speed and efficacy of synaptic transmission. Tight "nanodomain" channel-sensor coupling initiates transmitter release at synapses in the mature brain, whereas loose "microdomain" coupling appears restricted to early developmental stages. To probe the coupling configuration at a plastic synapse in the mature central nervous system, we performed paired recordings between mossy fiber terminals and CA3 pyramidal neurons in rat hippocampus. Millimolar concentrations of both the fast Ca(2+) chelator BAPTA [1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid] and the slow chelator EGTA efficiently suppressed transmitter release, indicating loose coupling between Ca(2+) channels and release sensors. Loose coupling enabled the control of initial release probability by fast endogenous Ca(2+) buffers and the generation of facilitation by buffer saturation. Thus, loose coupling provides the molecular framework for presynaptic plasticity.
authors: IST Austria (Institute of Science and Technology Austria), Am Campus 1, A-3400 Klosterneuburg, Austria.
authors: Nicholas P
authors: NP
authors: Vyleta
authors: Peter
authors: P
authors: Jonas
mesh_terms: D000818:Animals; D056654:CA3 Region, Hippocampal / Q000378:metabolism / Q000502:physiology; D015220:Calcium Channels / Q000378:metabolism*; D002614:Chelating Agents / Q000494:pharmacology; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D019599:Mossy Fibers, Hippocampal / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D009473:Neuronal Plasticity / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D013569:Synapses / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology*
chemical_list: D015220:Calcium Channels; D002614:Chelating Agents; D004533:Egtazic Acid; C025603:1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid