Figure 1.

CGRP immunohistochemistry in mouse vallate papillae. A, Schematic drawing of a lingual slice containing the vallate papilla. Red box represents approximate position of the taste buds in B. B, A Nomarski optics image was merged with an immunofluorescent confocal micrograph for this micrograph (CGRP/DIC). Numerous CGRP-immunoreactive nerve fibers forming a dense network (large arrows) are seen in the connective tissue core of the papilla. Fine CGRP-immunoreactive varicose nerve fibers (small arrows) running within, or in close association with, taste buds (areas of dashed lines) and coursing through the entire thickness of the epithelium, are clearly seen. The optical thickness (z-stack) of the confocal image is 13 μm. T, Trench. Scale bar, 50 μm. C, Ultrastructure of synapses in taste buds. C1, Synapses between a Presynaptic (Type III) cells and non–CGRP-immunoreactive nerve terminals (NT). The Presynaptic (Type III) cell (III) has an ovoid nucleus with deep invagination (★) as well as possesses many dense-cored vesicles (arrowheads), accumulation of clear vesicles (small arrows), and mitochondria at areas of membrane specialization (large arrow). C2, C3, Based on the intense electron-dense precipitate distributed diffusely throughout the cytoplasm of nerve processes, electron micrographs represent CGRP-immunoreactive nerve terminals in apparent contact with Presynaptic (Type III) cells. Inset, Higher magnification of the triangle in C2. The accumulation of clear (small arrows) and dense-cored vesicles (arrowhead) at areas of membrane specialization (large arrows) in C3 is seen. Scale bar, 500 nm.