ABSTRACT
Adult albino rats of the Sprague- Dawley strain were caged together for 24 hours [every three estrous females with an adult male] and their resultant embryos and off springs were used in this study. The tongues of ten animals in each of the following prenatal age groups [16 and 20 days or E16- Group I and E20- Group 2 respectively] and another ten in each of the following postnatal age groups [7 and 21 days or P7- Group 3 and P21 - Group 4] were used. The lingual papillae in the tongues of the different age groups were studied using both light and scanning electron microscopy. In the prenatal group 1 [E16], the dorsal lingual epithelium was noticed to be stratified squamous epitheliumn with poorly developed vallate papillae. No evidence of keratinization, fungiform, or filiform papillae were visible a the dorsal surface of the tongue, while in group 2 [E20], few fungiform papillae and numerous rounded tips of filiform ones became visible. Also, a thin layer of keratin was clearly located at the tip of each, filiforin papilla. At later stages of development [P7 and P21], the filiformn papillae appeared longer, more slender with pointed tips, and the keratin layer increased in thickness. The primordia of the circumvallate papillae appeared as small rounded elevated areas on the dorsal surface of the tongue at E16. At E20 a solid epithelial downgrowth appeared on either side of the papilla in which future taste bud cells appeared. The glitter started to open at P7 and became well formed at P21. The taste buds were identified on both walls of the developing gutter, and they then gradually enlarged. Taste bud cells became differentiated into gustatory and supporting cells at P7 to P21 age groups