RT Journal Article SR Electronic T1 Synaptic contributions to cochlear outer hair cell Ca2+ homeostasis JF bioRxiv FD Cold Spring Harbor Laboratory SP 2020.08.02.233205 DO 10.1101/2020.08.02.233205 A1 Marcelo J. Moglie A1 Diego L. Wengier A1 A. Belén Elgoyhen A1 Juan D. Goutman YR 2020 UL http://biorxiv.org/content/early/2020/08/02/2020.08.02.233205.abstract AB For normal cochlear function, outer hair cells (OHCs) require a precise regulation of intracellular Ca2+ levels. Influx of Ca2+ occurs both at the stereocillia tips and through the basolateral membrane. In this latter compartment, two different origins for Ca2+ influx have been poorly explored: voltage-gated Ca2+ channels (VGCC) at synapses with type II afferent neurons, and α9α10 cholinergic nicotinic receptors at synapses with medio-olivochlear complex (MOC) neurons. Using functional imaging, we report that these two Ca2+ entry sites are closely positioned, but present different regulation mechanisms. Ca2+ spread from MOC synapses is contained by cisternal Ca2+-ATPases. Considered a weak drive for transmitter release, we found that VGCC Ca2+ signals are larger than expected and can be potentiated by ryanodine receptors. Finally, we showed that sorcin, a highly expressed gene product in OHCs with reported Ca2+ control function in cardiomyocytes, regulates basal Ca2+ levels and MOC synaptic activity in OHCs.Competing Interest StatementThe authors have declared no competing interest.