Fine structure of taste buds in the human fungiform papilla

The fine structure of taste buds on fungiform papillae from man was examined with particular reference to different cell types and to cell-nerve contacts. Most of the elongated cells of the taste bud extended from the basal lamina to the apical pore, terminating in irregular microvilli. The cells contained clear apical vesicles, mitochondria, filament bundles and Golgi cisternae. Unmyelinated nerve fibers, containing mitochondria as well as both dense-cored and clear synaptic-type vesicles, were scattered throughout the whole taste bud but were most numerous at the base. The nerve fibers were either in simple appositional contact or in mesaxonal contact with the taste bud cell. Typical synapses with the postsynaptic densities in the taste bud cell were sometimes seen. In addition, single taste bud cells were observed to have more than one type of contact with nerve fibers. As in the Old World monkey Cynomolgus it was not possible to distinguish different cell types described earlier in other species.