Role of NAADP for calcium signaling in the salivary gland.

Coordination of intracellular Ca signaling in parotid acini is crucial for controlling the secretion of primary saliva. Previous work from our lab has demonstrated acidic-organelle Ca release as a participant in agonist-evoked signaling dynamics of the parotid acinar cell. Furthermore, results implicated a potential role for the potent Ca releasing second messenger NAADP in these events. The current study interrogated a direct role of NAADP for Ca signaling in the parotid salivary gland acinar cell. Use of live-cell Ca imaging, patch-clamp methods, and confocal microscopy revealed for the first time NAADP can evoke or enhance Ca dynamics in parotid acini. These results were compared with pancreatic acini, a morphologically similar cell type previously shown to display NAADP-dependent Ca signals. Findings presented here may be relevant in establishing new therapeutic targets for those suffering from xerostomia produced by hypofunctioning salivary glands.