Developmental change of alpha-gustducin expression in the mouse fungiform papilla.

Developmental changes in the distribution pattern of taste buds in newborn mouse have not been previously elucidated, and little work has been done to examine the postnatal alteration of the expression of alpha-gustducin in the mouse taste buds. In the present paper, we delineated the development and frequency distribution of the taste buds as well as the immunohistochemical expression of alpha-gustducin, a G protein closely related to the transduction of taste stimuli in the fungiform papilla from the birthday till the age of week 9. At birth, more than 45 taste buds (with or without pores) were observed on the fungiform papilla, then the number of mature taste buds increased rapidly, and resulted in 66% (80.2 +/- 0.6 of 122.2 +/- 1.3) of fungiform papilla taste buds containing taste pores at week 3. By age the total counts of pored taste buds continuously increased and their morphological features became quite discernible. They became ellipse in shape, characterized by distinct pores. Quantitative analysis of alpha-gustducin expression at different postnatal ages revealed a significant increase in the number of immunolabeled taste buds and alpha-gustducin-positive cells in single taste buds from week 1 to 7, by week 7, the number reached the value found in adults (99.3 +/- 0.9 and 8.3 +/- 0.3, respectively). These results indicated that taste buds within fungiform papilla play an important role in the detection of nutrients in the postnatal mouse.