Synapse-Level Determination of Action Potential Duration by K(+) Channel Clustering in Axons.
Synapse-Level Determination of Action Potential Duration by K(+) Channel Clustering in Axons.
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DOI：
10.1016/j.neuron.2016.05.035
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发表时间：
2016-07-20
期刊：
影响因子：
16.2
通讯作者：
Christie JM
中科院分区：
文献类型：
--
作者：
Rowan MJ;DelCanto G;Yu JJ;Kamasawa N;Christie JM
In axons, an action potential (AP) is thought to be broadcast as an unwavering binary pulse over its arbor driving neurotransmission uniformly at release sites. Yet, by recording from axons of cerebellar stellate cell (SC) interneurons, we show that AP width varies between presynaptic bouton sites, even within the same axon branch. The varicose geometry of SC boutons, alone, does not impose differences in spike duration. Rather, axonal patching revealed heterogeneous peak conductance densities of currents mediated mainly by fast-activating Kv3-type potassium channels, with clustered hot-spots at boutons and restricted expression at adjoining shafts. Blockade of Kv channels at individual boutons indicates that currents immediately local to a release site directs spike repolarization at that location. Thus, the clustered arrangement and variable expression density of Kv3 channels at boutons are key determinants underlying compartmentalized control of AP width in a near synapse-by-synapse manner, multiplying the signaling capacity of these structures. Rowan et al. find that APs are not uniformly represented across the axon arbor of SCs. Rather, spike duration is subject to local variation, determined at individual release sites, by clustering of fast-activating K+ channels thus contributing to release heterogeneity.
