Substance P in the superior cervical ganglion and the submaxillary gland of the rat.

Substance P has been detected in the superior cervical ganglion and submaxillary gland of the rat by radioimmunoassay. Decentralization, section of the carotid sinus nerve, or deefferentation does not affect the level of substance P in the rat superior cervical ganglion. Superior cervical ganglionectomy does not affect the amount of substance P in the submaxillary gland; however, section of the chorda tympani or duct ligation significantly reduces substance P in the submaxillary gland. It is concluded that substance P in the superior cervical ganglion is not located in the preganglionic sympathetic neurons, afferents from the glossopharyngeal nerve or post-ganglionic neurons projecting to the submaxillary gland or carotid body. Substance P does not appear to be associated with sympathetic innervation of the submaxillary gland, but it is anatomically and functionally related to the chorda tympani and possibly involved in the parasympathetic innervation of the gland. Substance P may also be present in gland cells of the submaxillary gland.