Intermediate filaments of the cytoskeleton in glandular cells of the rat fundic mucosa: immunofluorescence and electron microscopy study.
The organization of intermediate filaments (IF) in cells of the rat fundic mucosa was studied by electron microscopy and immunofluorescence microscopy using specific antiprekeratin antibodies on frozen sections and isolated cells. Our results suggest that mucous cells lining the gastric surface and the gastric pits, which appeared strongly decorated, are the most rich in IF. These cells displayed coarse bundles of IF oriented in all directions as well as desmosome-attached tonofibrils. Mucous neck cells contained fewer bundles of IF located preferentially toward the apical region. Zymogen cells showed a strong staining along the contour of the luminal border, together with a faint decoration of a fine meshwork extending throughout the cytoplasm. A poorly defined fibrillar cortex present underneath the secretory plasma membrane and sparse bundles of IF among the elements of the rough endoplasmic reticulum were seen in thin sections. In contrast, parietal cells appeared brightly stained and the prekeratinlike material formed a cortical polygonal meshwork especially visible in isolated cells. A developed system of IF formed by conspicuous bundles located underneath the secretory canaliculi, among the mitochondria and in the vicinity of the basal plasma membrane, was observed in the electron microscope.