Abstract
The adrenal medulla of the rat, mouse and guinea pig was freeze-dried and treated with formaldehyde vapor according to the method of FALCK and HILLARP. Sections were observed by fluorescence and ordinary microscopy.
The noradrenalin storing NA cells intensely fluoresced orange, while the adrenalin storing A cells, yellow under the fluorescence microscope. In ordinary light the NA cells contained brown granules as in the specimens after chromaffin reaction.
The cytoplasmic granules of the A cells were selectively stained by toluidine blue and pseudoisocyanin. The basophilic substance showed no tendency to decrease after immersion in distilled water, while the formaldehyde induced fluorescence was considerably reduced. In the reserpinized rats, a remarkable decrease in the metachromatic substance together with the specific fluorescence was recognized.
It was suggested that the basophilic substance was the glutamate-rich soluble protein (chromogranin) contained in the secretory granules of the A cells. The possible reasons for the selective concentration of this stained substance in the A cells were considered.
