Parasympathetic activation of amylase secretion in the intact and sympathetically denervated rat parotid gland.

Observations were made on amylase secretion from the rat parotid gland induced by parasympathetic nerve stimulation in vivo. In spite of a low salivary amylase concentration a large total amylase output, equivalent to 36% of initial gland content, was found on prolonged activation (5 Hz, 120 min). However, no decrease in gland amylase content was found, which indicates that the output of amylase was balanced by synthesis. We suggest that prolonged, parasympathetically induced amylase secretion is dependent on activation of amylase synthesis and that the secretion is mainly of non-granular origin. Parasympathetic nerve stimulation produced an even larger amylase output from sympathectomized glands. Even under these conditions gland amylase content was unchanged and no obvious degranulation was found when the glands were examined after stimulation. This is in marked contrast to the decrease in amylase content and to the degranulation which are found after sympathetic activation.