Maturation of taste buds on the soft palate of the postnatal rat.

Taste bud distribution on the soft palate and within three types of tongue papillae (fungiform, foliate, and circumvallate) were examined histologically in the rat at different postnatal ages. After paraffin embedding, serial sections (10 microm) were made and stained by HE, and digitized images of each section were examined. The existence of a taste pore was used to identify mature taste buds. At birth, 53% (68 of 127 observed) of the taste buds on the soft palate, but only 14% (14 of 110 observed) within fungiform papillae, contained a taste pore. One week after birth, the number of mature taste buds increased rapidly, resulting in 90% of soft palate taste buds and 80% of fungiform taste buds containing taste pores. In contrast, no taste buds with pores were observed at birth within foliate and circumvallate papillae; however, at two weeks after birth 52% (71 of 132 observed) of the foliate and 68% (180 of 267 observed) of the circumvallate taste buds examined contained taste pores. These results suggest that taste buds within the soft palate play an important role in the detection of nutrients in the neonatal rat.