Ultrastructural cytochemistry of atrial muscle cells. III. Reactivity of specific granules in man.

The carbohydrate content of human auricular specific granules was assessed by a variety of cytochemical and histochemical methods. The specific granules were found to be argentaphobic, when ultrathin sections of Araldite-embedded auricular appendages were stained according to the periodic acid-thiocarbohydrazide-silver proteinate technique of Thiery. The entire core of these granules was moderately positive after ultrathin sections of glutaraldehyde-fixed, glycol methacrylate-(GMA-) embedded auricles were stained with phosphotungstic acid (PTA) at a low pH. A similar reaction was shown by the cell coat, residual bodies (C-granules), lysosomes, Z-dises as well as by a very small portion of the Golgi complex. Analogous results were obtained in semithin sections of GMA-embedded auricles stained according to the periodic acid-Schiff (PAS) technique. In terms of the current state of cytochemical knowledge, these findings indicate that specific granules may contain complex carbohydrates. The possible functions of specific granules, in relation to the Golgi complex, are discussed in the light of the present observations.