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bioRxiv · 10.1101/2020.12.30.424864

The characteristics of intracellular Ca2+ signals in vivo necessitate a new model for salivary fluid secretion

Yule, D. I.·Takano, T.·Wahl, A. M.·Huang, K. T.·Rugis, J.·Sneyd, J.
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Abstract

Salivary fluid secretion involves an intricate choreography to result in the trans-epithelial movement of NaCl and water into the acinus lumen. Current models are based on experimental observations in enzymatically isolated cells where the Ca2+ signal invariably propagates globally and thus appears ideally suited to activate spatially separated Cl and K channels. We monitored Ca2+ signals and salivary secretion in live mice expressing GCamp6F, following stimulation of the nerves innervating the submandibular gland. Consistent with in vitro studies, Ca2+ signals were initiated in the apical endoplasmic reticulum. In marked contrast to in vitro data, highly localized trains of Ca2+ transients that failed to propagate from the apical region were observed. Following stimuli optimum for secretion, large apical-basal gradients were elicited. Given this incompatibility to the previous model, a new mathematical model was constructed to explain how salivary secretion can be efficiently stimulated by apically localized Ca2+ signals.

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Yule, D. I., Takano, T., Wahl, A. M., Huang, K. T., Rugis, J., Sneyd, J.. 2021-01-01. The characteristics of intracellular Ca2+ signals in vivo necessitate a new model for salivary fluid secretion. https://doi.org/10.1101/2020.12.30.424864

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