Ultrastructure and immunocytochemistry of gustatory cells in man.

Ultrastructural and immunocytochemical features of the taste buds of the vallate, foliate and fungiform papillae in young, adult and elderly men, revealed three types of sensorial cells: dark type I cells rich in free ribosomes and large dense granules, light type II cells with large amorphous areas of cytoplasmic matrix and light type III cells with a dense core immunoreactive for 5-HT. All sensorial cells send microvillous protrusions of the apical cytoplasm into the gustative canal and make contact with nerve endings. After comparative studies, we made several hypothetical propositions on the functional value of microvillous protrusions, as well as on the apical and basal dense core vesicles of the foliate and vallate papillae. Moreover, we think that sensorial cells are implicated in taste transduction and that subject age does not seem to play any role in taste perception.