Papilla palatina, nasopalatine duct and taste buds of young and adult rats.

The morphology of the papilla palatina, the nasopalatine ducts and the taste buds situated within these ducts was studied in pups and adult rats using light and electron microscopy. During development, the papilla palatina grew in width and depth, becoming a protuberance in weanlings and adults. The nasopalatine ducts enlarged and two folds of the lateral walls of the ducts differentiated, reducing the width of the tubes in the region of the oral openings. Taste buds appeared postnatally. Light, dark, and perigemmal cells were found in all stages studied, but light cells were scarce up to 8 days of age. The taste pore appeared between 11 and 13 days of age; it lacked electron-dense material of cellular origin. Synaptic-like images could be found only in relation to dark cells. The papilla palatina, the nasopalatine ducts and the taste buds were fully developed by the 3rd week of life.