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

David I Yule, Takahiro Takano, Amanda M Wahl, Kai Ting Huang, John Rugis, James Sneyd
2021 bioRxiv   pre-print
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
more » ... ves 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.
doi:10.1101/2020.12.30.424864 fatcat:2xvobukic5guldjv5hn3m7zota