Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.08.02.233205v1?rss=1 Authors: Moglie, M. J., Wengier, D. L., Elgoyhen, A. B., Goutman, J. Abstract: 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 910 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. Copy rights belong to original authors. Visit the link for more info