An ultrastructural study of the nasal mucosa by rapid freezing and freeze-substitution.

We demonstrated the ultrastructures of the nasal mucosa of the rat by rapid freezing and freeze substitution with OsO4. Liquid helium was used for the rapid freezing. The depth of the good preservation was approximately 20 micron below the cut surface of the tissue. The characteristic features of the nasal mucosa obtained here are as follows: 1) The cross-section profiles of the cilium were round and smooth. 2) Mitochondrial matrix was electron dense and a few dense granules were observed in it. 3) Secretory granules of the goblet cells were enclosed by a limited membrane. 4) Extracellular space was of variable widths. 5) Cytoplasmic filaments were well preserved.