Aquaporin-5 Protein Is Selectively Reduced in Rat Parotid Glands under Conditions of Fasting or a Liquid Diet.

Aquaporin-5 (AQP5) water channel, transmembrane protein 16A (TMEM16A) Ca-activated Cl channel, and Na-K-2Cl cotransporter (NKCC1) are membrane proteins on salivary gland acinar cells that function in watery saliva secretion. We examined their expression changes in rat parotid glands under reduced mastication. Rats were either fed regular chow as a control group, fasted for 48 hr or fed a liquid diet for 48 hr or 1 week to reduce mastication.

Long-term Pilocarpine Treatment Improves Salivary Flow in Irradiated Mice.

Radiation therapy for head and neck cancer frequently causes salivary gland dysfunction. Pilocarpine is a clinically approved and effective drug that induces saliva secretion, thereby keeping the oral mucosa moist and reducing discomfort in patients, but the effect is transient. We expected that this drug also has beneficial long-term effects that maintain the integrity of salivary glands by reducing, for instance, apoptosis.