Abstract
The oral cavity base and inferior surface of the tongue excised from 5 male and 5 female adult Wistar-strain rats and 6 male and 4 female adult SMAstrain mice were observed by scanning and light microscopy. The following results were obtained.
1. The caruncula sublingualis of the oral cavity base of the rat displayed several eminences, taste-bud papillae, which generally possessed 1 to 4 taste buds in each tip. A pair of excretory ducts from the sublingual glands opened on the posterior part of the carunculae, and ducts from the submaxillary glands penetrated the centers of the carunuculae.2. Taste-bud papillae were observed rarely in the oral cavity base of the rat apart from the carunculae. These taste-bud papillae resembled fungiform papillae in shape, except for having 1 to 3 taste buds and no epithelial mantle.3. Filiform and fungiform papillae were scattered only over the tip and marginal part of the inferior surface of the tongue. The other parts of the inferior surface were covered with thick and cornified mucous epithelial cells, and low wave-like eminences were present there. It is suggested that the microridges of the cell surface represent a structure adapted for the mastication of ingested substances.4. In the oral cavity base of the mouse, taste-bud papillae appeared only in the carunuculae. The number of taste buds was fewer than that in the rat.5. The taste buds in the carunculae of the rat and mouse were distributed around the orifices of the excretory ducts of the salivary glands. This suggests that saliva released from orifices near the taste buds may strengthen the activation of the taste receptors to perceive taste quickly.
