AUTORADIOGRAPHIC LOCALIZATION OF BINDING-SITES FOR 2ND MESSENGERS ON NEURONS AND ASTROCYTES OF CULTURED RAT CEREBELLUM

Using autoradiographic techniques, studies on the cellular localization of binding sites for second messengers in explant cultures of rat cerebellum have been performed. Binding of [H-3]inositoltrisphosphate ([H-3]IP3), [H-3]phorbol dibutyrate ([H-3]PDBu) occurred to Purkinje cells whereas binding sites for [H-3]forskolin were mainly confined to granule cells and outgrowing nerve fibres. A great number of astrocytes was also labelled by all three radio-ligands. Binding of [H-3]IP3, [H-3]PDBu and [H-3]forskolin was displaced by unlabelled compounds, suggesting specific binding. Our observations provide strong evidence that in addition to neurones, astrocytes also express binding sites for second messengers.