Autoradiographic localization of binding sites for neuropeptide Y and bradykinin on astrocytes.

The cellular localization of binding sites for the vasoactive peptides 125I-neuropeptide Y (NPY) and 3H-bradykinin (BK) was studied in explant cultures of rat cerebellum, brain stem and spinal cord by means of autoradiography. The majority of astrocytes in these cultures expressed binding of 125I-NPY and 3H-BK over their cell bodies and processes. Simultaneous staining of the cultures with anti-glial fibrillary acidic protein (GFAP) has shown that the labelled cells were GFAP-positive and could therefore be identified as astrocytes. In addition to glial cells, a great number of neurones also revealed binding sites for the neuropeptides. Our autoradiographic findings together with recent electrophysiological studies provide good evidence for the existence of NPY- and BK-receptors on astrocytes.