[Three-dimensional structure of the connective tissue core of the lingual papillae in the crab-eating macaque (Macaca fascicularis)].

The three-dimensional structure of the connective tissue core (CTC) of the four types of lingual papillae of the crab-eating macaque (Macaca fascicularis) was studied by scanning electron microscopy after removal of the epithelial cell layer by long-term treatment with hydrochloric acid at room temperature and compared with the results obtained from light microscopy. 1) Filiform papillae are densely distributed on the dorsal surface of the anterior two thirds of the tongue. Fungiform papillae are scattered among these filiform papillae, and are numerous at the anterior margin of the tongue. The connective tissue core of each filiform papilla looked like a lifting human hand with its palm towards the tongue tip. By using light microscopy, AF-positive elastic fibers were accumurated very densely just beneath the basal region of the anterior column epithelium of each filiform papilla. 2) CTC of fungiform papilla showed coralliform structure whose branches were ramified a few times. On the top of each branch there was a small depression where a taste bud was situated. 3) After removal of the epithelial cell layer of the foliate papilla, longitudinal grooves coinciding with the epithelial slits were observed. Some glandular ducts were seen protruding towards the exfoliated epithelium. 4) After removal of the covering epithelium of the vallate papilla, numerous small rod-shaped secondary CT cores appeared on the large primary CT core.