Zio staining of monoaminergic granulated vesicles

Abstract

To study zinc iodide-osmium tetroxide (ZIO) staining in monoaminergic granulated vesicles, pineal glands of rat and mouse, and vas deferens, splenic arteries and adrenal glands from rats were used. Fixation was carried out in ZIO at 4 and 20 °C for 2, 15 and 24 h. The core of granulated vesicles of monoaminergic nerves and medullary cells was stained with variable intensity with all the schedules tested. With ZIO at 4 °C for 2 h only the matrix of granulated vesicles from pineal nerves were deeply stained. When the reaction was prolonged to 24 h positive reaction was observed in the matrix of a few chromaffin granules of the adrenal medulla. At 20 °C the matrix of the granulated vesicles of the pineal gland, vas deferens and splenic artery nerves reacted intensely. In the adrenal medulla the matrix of a large proportion of granulated vesicles in one type of cell was deeply stained with ZIO at 20 °C. Thus, different kinds of granulated vesicle show a differential ZIO affinity according to the temperature. The time of impregnation may also influence the staining. The core and the matrix react differentially with ZIO in the monoaminergic granulated vesicles.