An electrophysiological study of the postnatal development of the autonomic innervation of the rat submandibular salivary gland.

The development of the functional relationship between the autonomic nerves that regulate secretion and the acini of the gland (SMG) was studied. Electrophysiologic studies indicated that stimulation of the parasympathetic nerves at birth caused the secretion of fluid from the duct system but did not cause protein secretion from the developing acini or terminal tubules. Stimulation of the sympathetic innervation (superior cervical ganglion) did not cause protein secretion from developing acini or terminal tubules until 5 days after birth. The amount of protein released progressively increased in response to electrical stimulation of the cervical ganglion as the animals aged. This increased secretory response was correlated with the appearance of increasing numbers of catecholamine-containing neurones in the gland parenchyma.