| Autor: |
Roshchin MV; Institute of Higher Nervous Activity and Neurophysiology, Moscow 117485, Russia., Matlashov ME; Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow 117997, Russia., Ierusalimsky VN; Institute of Higher Nervous Activity and Neurophysiology, Moscow 117485, Russia., Balaban PM; Institute of Higher Nervous Activity and Neurophysiology, Moscow 117485, Russia., Belousov VV; Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow 117997, Russia.; Pirogov Russian National Research Medical University, Moscow 117997, Russia.; Institute for Cardiovascular Physiology, Georg August University Göttingen, D-37075 Göttingen, Germany., Kemenes G; Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton BN1 9QG, UK., Staras K; Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton BN1 9QG, UK., Nikitin ES; Institute of Higher Nervous Activity and Neurophysiology, Moscow 117485, Russia. |
| Abstrakt: |
Action potential shape is a major determinant of synaptic transmission, and mechanisms of spike tuning are therefore of key functional significance. We demonstrate that synaptic activity itself modulates future spikes in the same neuron via a rapid feedback pathway. Using Ca 2+ imaging and targeted uncaging approaches in layer 5 neocortical pyramidal neurons, we show that the single spike-evoked Ca 2+ rise occurring in one proximal bouton or first node of Ranvier drives a significant sharpening of subsequent action potentials recorded at the soma. This form of intrinsic modulation, mediated by the activation of large-conductance Ca 2+ /voltage-dependent K + channels (BK channels), acts to maintain high-frequency firing and limit runaway spike broadening during repetitive firing, preventing an otherwise significant escalation of synaptic transmission. Our findings identify a novel short-term presynaptic plasticity mechanism that uses the activity history of a bouton or adjacent axonal site to dynamically tune ongoing signaling properties. |
