LAUSR

What is the central question of this study? The effects of Ca2+ responses on salivary fluid secretion have been studied indirectly by monitoring ion channel activities and other indices. Therefore, Ca2+ responses during salivary secretion remain poorly understood. What is the main finding and its importance? Herein, we developed a simultaneous monitoring system for Ca2+ responses and salivary secretion in live animals using a YC‐Nano50‐expressing submandibular gland and a fibre‐optic pressure sensor. This new approach revealed a clear time lag between the onset of Ca2+ responses and salivary secretion. We also estimated the [Ca2+]i and provided direct evidence for the regulation of salivary secretion by small increases in [Ca2+]i in submandibular gland acinar cells.