α-Gustducin-immunoreactive solitary chemosensory cells in the developing chemoreceptorial epithelium of the rat vallate papilla

Abstract

The presence of solitary chemosensory cells was studied in rat vallate papillae during the first week of post-natal life by α-gustducin immunocytochemistry. In 1- to 3-day-old rats, isolated α-gustducin-immunoreactive cells were found within the epithelium of the vallate papilla. These cells, mainly located in the basal layer were scattered among keratocytes and wrapped in α-gustducin-negative epithelial cells in a glia-like fashion. The α-gustducin-immunoreactive cells were usually round and some of them gave rise to short, large processes directed towards the lumen of the oral cavity or the basal lamina. Rarely, some cells showed an evident bipolar shape. Small taste buds containing either α-gustducin-immunoreactive or α-gustducin-negative cells appeared in the vallate papillae of 4-day-old rats in which isolated, bipolar-shaped α-gustducin-immunoreactive cells were also found. After the first week of post-natal life, the taste buds appeared basically similar to those of adult animals. In conclusion, the present study demonstrates that the presence of epithelial cells with characteristics of solitary chemosensory cells precedes the development of the taste buds.