Brevican “nets” voltage-gated calcium channels at the hair cell ribbon synapse

During hearing in mammals, “sensorineural” inner hair cells convert sound wave-generated mechanical input into electrical activity, resulting in glutamate release onto type I spiral ganglion neurons (SGNs) at specialized synapses known as “ribbon synapses”. New findings published here in BMC Biology by Sonntag and colleagues indicate a role for the proteoglycan Brevican in forming perineurounal net (PNN) baskets at these synapses and controlling the spatial distribution of presynaptic voltage-gated calcium channels that regulate glutamate release. These findings may provide insight into the mechanism by which individual ribbon synapses within a single hair cell can function in an independent manner to facilitate hearing within a broad dynamic range.