title: Ultrafast action potentials mediate kilohertz signaling at a central synapse.
abstract: Fast synaptic transmission is important for rapid information processing. To explore the maximal rate of neuronal signaling and to analyze the presynaptic mechanisms, we focused on the input layer of the cerebellar cortex, where exceptionally high action potential (AP) frequencies have been reported in vivo. With paired recordings between presynaptic cerebellar mossy fiber boutons and postsynaptic granule cells, we demonstrate reliable neurotransmission up to ∼1 kHz. Presynaptic APs are ultrafast, with ∼100 μs half-duration. Both Kv1 and Kv3 potassium channels mediate the fast repolarization, rapidly inactivating sodium channels ensure metabolic efficiency, and little AP broadening occurs during bursts of up to 1.5 kHz. Presynaptic Cav2.1 (P/Q-type) calcium channels open efficiently during ultrafast APs. Furthermore, a subset of synaptic vesicles is tightly coupled to Ca(2+) channels, and vesicles are rapidly recruited to the release site. These data reveal mechanisms of presynaptic AP generation and transmitter release underlying neuronal kHz signaling.
authors.affiliation: Carl-Ludwig-Institute for Physiology, Medical Faculty, University of Leipzig, Liebigstr. 27, 04103 Leipzig, Germany; European Neuroscience Institute Göttingen, Grisebachstr. 5, 37077 Göttingen, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Ritzau-Jost
authors.affiliation: Carl-Ludwig-Institute for Physiology, Medical Faculty, University of Leipzig, Liebigstr. 27, 04103 Leipzig, Germany; European Neuroscience Institute Göttingen, Grisebachstr. 5, 37077 Göttingen, Germany.
authors.forename: Igor
authors.initials: I
authors.lastname: Delvendahl
authors.affiliation: Carl-Ludwig-Institute for Physiology, Medical Faculty, University of Leipzig, Liebigstr. 27, 04103 Leipzig, Germany; European Neuroscience Institute Göttingen, Grisebachstr. 5, 37077 Göttingen, Germany.
authors.forename: Annika
authors.initials: A
authors.lastname: Rings
authors.affiliation: Carl-Ludwig-Institute for Physiology, Medical Faculty, University of Leipzig, Liebigstr. 27, 04103 Leipzig, Germany; European Neuroscience Institute Göttingen, Grisebachstr. 5, 37077 Göttingen, Germany.
authors.forename: Niklas
authors.initials: N
authors.lastname: Byczkowicz
authors.affiliation: Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria.
authors.forename: Harumi
authors.initials: H
authors.lastname: Harada
authors.affiliation: Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria.
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Shigemoto
authors.affiliation: Carl-Ludwig-Institute for Physiology, Medical Faculty, University of Leipzig, Liebigstr. 27, 04103 Leipzig, Germany; Department of Neurogenetics, Max-Planck-Institute for Experimental Medicine, Hermann-Rein-Strasse 3, 37075 Göttingen, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Hirrlinger
authors.affiliation: Carl-Ludwig-Institute for Physiology, Medical Faculty, University of Leipzig, Liebigstr. 27, 04103 Leipzig, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Eilers
authors.affiliation: Carl-Ludwig-Institute for Physiology, Medical Faculty, University of Leipzig, Liebigstr. 27, 04103 Leipzig, Germany; European Neuroscience Institute Göttingen, Grisebachstr. 5, 37077 Göttingen, Germany. Electronic address: hallermann@medizin.uni-leipzig.de.
authors.forename: Stefan
authors.initials: S
authors.lastname: Hallermann
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D002525:Cerebellar Cortex / Q000166:cytology / Q000502:physiology; D051379:Mice; D008810:Mice, Inbred C57BL; D015398:Signal Transduction / Q000502:physiology*; D013569:Synapses / Q000502:physiology*; D013997:Time Factors