IMMUNOCYTOCHEMICAL DISTRIBUTION OF SEROTONIN AND NEUROPEPTIDE-Y (NPY)IN MOUSE ADRENAL-GLAND

By the use of immunocytochemical staining methods, we studied the morp hology and distribution of 5HT and NPY immunoreactive cells and fibres in the mouse adrenal gland. The 5HT-immunoreactive cells were numerou s and widely localized in the medullar tissue. These cells were arrang ed in three cellular types with regard to their morphological and immu nocytochemical features. One of them showed cells with polygonal shape , being intensified like the typical medullary chromaffin cells. These immunoreactive cells were observed arranged in medullar islets. The s econd 5HT-immunoreactive celular type was constituted by cells with po lygonal shape and strong immunoreactivity. The third one was formed by cells with immunoreactive prolongations. We found some islets of chro maffin non-immunoreactive cells surrounded by immunostained cells. We also observed some 5HT-immunoreactive nerve fibres in the medullar tis sue. NPY-like immunoreactivity was detected in both chromaffin and gan glion cells in adrenal medulla. NPY-like immunoreactivity was also det ected in nerve fibres at cortical level. In a few cases, we observed m edullar 5HT- and NPY-immunoreactive tissue in the adrenal cortex (mono tremas).