COLOCALIZATION OF BINDING-SITES FOR SOMATOSTATIN, MUSCARINE AND NICOTINE ON CULTURED NEURONS OF RAT NEOCORTEX, CEREBELLUM, BRAIN-STEM AND SPINAL-CORD - COMBINED AUTORADIOGRAPHIC AND IMMUNOHISTOCHEMICAL STUDIES

The cellular localization of binding sites for [I-125]-tyramine somato statin [I-125]SS) was studied in explant cultures of rat CNS by autora diography. In cultures from cortex, brain stem and spinal cord many ne urones revealed binding sites fbr the peptide whereas in cerebellar cu ltures only little binding of[I-125]SS was observed. In addition to ne urones, astrocytes were also labelled by the peptide. By combined immu nohistochemical and autoradiographic techniques, it was demonstrated t hat the majority of neurones which expressed binding sites for [I-125] SS were also immunostained by the monoclonal cholinergic muscarinic or nicotinic receptor antibodies (M 35 and W 6, respectively), providing evidence for a colocalization of cholinergic and somatostatin recepto rs on the neuronal membrane.