The nucleus parvocellularis reticularis regulates submandibular-sublingual salivary secretion in the rat: a...

This experiment shows that activation of the nucleus parvocellularis reticularis in the rat brainstem provokes salivary hypersecretion by the submandibular-sublingual glands. The secretory effect is mediated by cholinergic mechanisms, as the administration of atropine blocked the flow of saliva evoked by stimulation of the nucleus parvocellularis. In contrast, injection of dihydroergotamine (an alpha-blocker) and/or propranolol (a beta-blocker) failed to significantly reduce submandibular and sublingual salivary secretion when compared to a control group injected with distilled water. The cholinergic nature of the salivary response suggests that the nucleus parvocellularis reticularis exerts its secretory effect on the salivary glands parasympathetically rather than through mechanisms associated with sympathetic pathways. The area of the brainstem activated in the present study closely overlaps the region in which cell bodies of superior salivatory neurons have recently been identified with retrograde transport of peroxidase. The data presented herein represent functional proof in support of the location of the superior salivatory nucleus within the parvocellularis reticular formation.