[Ultrastructural identification and immunocytochemical study of somatostatin cells in antral mucosa of the rabbit and the mouse (author's transl)].

In normal and L-Dopa treated rabbits and mice, combined immunochemical methods, photonic histological methods for endocrine cells and ultrastructural methods were used to elucidate ultrastructure and properties of somatostatin cells of the antral mucosa. In normal rabbits, immunoreactive cells giving no fluorescence with Falck's technic, they corresponded neither to serotonin cells nor gastrin cells; they were unreactive with Fontana, Hellerström-Hellmann, Sevier-Munger and Mac Conaill methods but very slightly stained with Grimelius methods. In L-Dopa treated animals somatostatin cells gave formaldehyde induced fluorescence (they were included in GIC cells, thus in Apud group), exhibited a good reaction with Grimelius and Sevier-Munger methods. In order to carry out the alternate semi-thin/thin section procedure (semi-thin sections for immunofluorescence or immunoenzymatic detection and serial thin sections counter-stained for conventional ultrastructure studies), immunological treatment were performed on M.F.F.--glutaraldehyde fixed small fragments of mucosa before inclusion in Epon 812 or, after inclusion, on semi-thin sections. We succeeded in identifying ultrastructurally somatostatin cells. They displayed round or ovoïd shaped secretory granules, and three constant typical structures: numerous microfilaments--light and homogenous granules, often seeming like lipids---granules made up by coarsely filamentous cores surrounded by a large empty halo. Somatostatin cells seemed different of X cells because of their predominant localisation in the antral mucosa (in the rabbit X cells were predominantly in the fundus) and because of the lack of nuclear microfilaments; they also seemed ultrastructuraly different of D1 cells.