IMMUNOHISTOCHEMICAL DISTRIBUTION OF CALCITONIN-GENE-RELATED PEPTIDE IN NERVE-FIBERS OF THE ANTERIOR BUCCAL GLAND OF THE RAT

Calcitonin gene-related peptide immunoreactive (CGRP-IR) nerves in rat were studied as to their distribution and origin in anterior buccal g lands, which are unique minor mucous salivary glands in the rat. A mod erate number of CGRP-IR nerve fibres were located, mostly perivascular ly and around intralobular ducts, but they were also found around acin i. The latter fibres were mainly of sensory origin, as suggested by th eir disappearance after denervation of the ophthalmic and maxillary br anches of the trigeminal nerve. On the contrary, CGRP-IR nerves around interlobular ducts and some of those in a perivascular location remai ned both after sensory denervation and after extirpation of the sympat hetic superior cervical ganglion. Whether these fibres originate in do rsal root ganglia C-3-C-4 or represent parasympathetic fibres is not k nown. Based on the present data and the previous findings showing a re gulatory role of CGRP both on blood and salivary flow, it is possible that CGRP in sensory, and possibly also in parasympathetic nerves, par ticipates in the regulation of reflex blood flow and salivary secretio n in the anterior buccal gland of the rat.