Immunocytochemistry on the localization of 5-hydroxytryptamine in monkey and rabbit taste buds.

Immuno-electron microscopy with the protein A-gold method demonstrated immunoreactive gold particles against 5-hydroxytryptamine localized in cored vesicles aggregating around presynaptic terminals of the gustatory cells in monkey and rabbit taste buds. The positive reactions were also found in the intragemmal and subepithelial nerve fibers. The role of these cored vesicles in taste transduction is still uncertain but the data strongly suggest that they may participate in a serotonergic modulation of a cholinergic synaptic transmission from the gustatory cells to the nerve endings.