Ultrastructure of the nerve endings in the rat tongue mucosa.

Ultrastructure of the sensory nerve endings in the dorsal tongue mucosa of Sprague Dawley rats was described. Thick bundles of nerve endings, the presence of branches and organized or free nerve endings were found in the subepithelial space. Lamellar corpuscles containing several terminal axons were found in close contact with basal lamina of the epithelium. The lamellar cells envelope the axons at different levels. The cytoplasm of lamellae contains numerous microfilaments, microtubules, mitochondria and caveolae. The terminal axons measure 0.5 to 1.0 micron in diameter and present several forms. Short axoplasmic protrusions and dilated ends were observed. The axons contain numerous mitochondria, microtubules, neurofilaments and small clear vesicles.