Fine structure of the lingual dorsal surface of the bullfrog.

There have been many reports on the ultrastructure of the lingual taste organs, sensory papillae, of frogs (Uga, 1966; Uga and Hama, 1967; Graziadei and DeHan, 1971; Stensaas, 1971; Hirata and Nada, 1975; During and Andres, 1976; Jeager and Hillman, 1976; Graziadei, 1975). However, among these papers, only a few describe tridimensional ultrastructural studies on the lingual epithelial surface by scanning electron microscopy (Graziadei and DeHan, 1971; During and Andres, 1976; Graziadei, 1975). In vertebrates including amphibia, it has proved difficult to observe the real surface of the oral epithelial cells using scanning electron microscopy because of the mucus which covers them. It has recently become possible to examine the intact cell surface of the mammalian tongue by scanning electron microscopy in a better condition than formerly due to advances in the removal of extracellular material by acid hydrolysis (Iwasaki et al., 1983, 1984a, b, c). In the present study, this method was applied to the lingual dorsal epithelial cells and sensory organs of the bullfrog to investigate their ultrastructures by scanning electron microscopy.