Salivary secretion assay.

Twelve-week-old mice of both sexes and of wild-type and DFX genotypes were used to measure saliva secretion. Anesthesia was induced with 5% isoflurane and oxygen and maintained under a 2% isoflurane and 98% oxygen through a nose cone. Saliva secretion was stimulated by subcutaneous injection of 50 μl of pilocarpine solution (100 μM dissolved in isotonic saline). Saliva was collected for 15 min using a narrow (0.5 mm outside diameter) catheter attached to an Eppendorf tube connected to a vacuum. Weight and volume of collected saliva were measured after the 15 min collection time.