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A sensory cell diversifies its output by varying Ca²⁺ influx-release coupling among active zones.

ABSTRACT: The cochlea encodes sound pressures varying over six orders of magnitude by collective operation of functionally diverse spiral ganglion neurons (SGNs). The mechanisms enabling this functional diversity remain elusive. Here, we asked whether the sound intensity information, contained in the receptor potential of the presynaptic inner hair cell (IHC), is fractionated via heterogeneous synapses. We studied the transfer function of individual IHC synapses by combining patch-clamp recordings with dual-color Rhod-FF and iGluSnFR imaging of presynaptic Ca²⁺ signals and glutamate release. Synapses differed in the voltage dependence of release: Those residing at the IHC' pillar side activated at more hyperpolarized potentials and typically showed tight control of release by few Ca²⁺ channels. We conclude that heterogeneity of voltage dependence and release site coupling of Ca²⁺ channels among the synapses varies synaptic transfer within individual IHCs and, thereby, likely contributes to the functional diversity of SGNs. The mechanism reported here might serve sensory cells and neurons more generally to diversify signaling even in close-by synapses.

SUBMITTER: Ozcete OD

PROVIDER: S-EPMC7917556 | biostudies-literature | 2021 Mar

REPOSITORIES: biostudies-literature

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A sensory cell diversifies its output by varying Ca<sup>2+</sup> influx-release coupling among active zones.

Özçete Özge D ÖD Moser Tobias T

The EMBO journal 20201221 5

The cochlea encodes sound pressures varying over six orders of magnitude by collective operation of functionally diverse spiral ganglion neurons (SGNs). The mechanisms enabling this functional diversity remain elusive. Here, we asked whether the sound intensity information, contained in the receptor potential of the presynaptic inner hair cell (IHC), is fractionated via heterogeneous synapses. We studied the transfer function of individual IHC synapses by combining patch-clamp recordings with du ...[more]

PMID: 33346936

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A sensory cell diversifies its output by varying Ca²⁺ influx-release coupling among active zones.

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A sensory cell diversifies its output by varying Ca<sup>2+</sup> influx-release coupling among active zones.

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A sensory cell diversifies its output by varying Ca2+ influx-release coupling among active zones.

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A sensory cell diversifies its output by varying Ca<sup>2+</sup> influx-release coupling among active zones.

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A sensory cell diversifies its output by varying Ca²⁺ influx-release coupling among active zones.