Regeneration of fungiform taste buds: Temporal and spatial characteristics

Abstract

The gross morphology of the tongue of the Mongolian gerbil ( Meriones unguicultatus ), the location of papillae and taste buds, and the normal innervation pattern of the tongue asnd taste buds were determined. The chorda tympani nerve was interrupted to produce degeneration of fungiform taste buds. Regenerating chorda tympani axons followed the original nerve pathways in the tongue en route to the furniform papillae in the epithelium where they initiated the regeneration of taste buds. The spastial distribution of reinnervated fungiform papillae and reformed taste buds was examined 7 to 19 days following surgery. Beginning at eight days following chorda tympani interruption there was a progressive increase, first, in the proportion of fungiform papillae that were reinnervated, and later in the number of reformed taste buds. On the basis of these measures it was concluded that a taste bud is reformed one to two days after reinnervation of its papilla. From the time course of reinnervation of the fungiform papillae it was calculated thast some fibers regenerated at rates in excess of 2mm/day. Regeneration was precise and systematic. The regenerating chorda tympani fibers accurately returned to the fungiform papillae; they did not follow the pasthways of lingual nerve axons. In the initial stages of recovery both reinnervated papillae and reformed taste buds weere preferentially located toward the front of the tongue; the reinnervation of posterior fungiform papillae was delayed.