Localisation of receptors using a dimeric ligand and electron immunocytochemistry

The role of regulatory peptides and the existence of specific peptide receptors are becoming established. However, techniques for the ultrastructural localisation of these receptors are fraught with difficulties. We propose here a novel technique for receptor localisation using a dimeric peptide ligand and electron microscopical immunocytochemistry. The dimeric ligand is used as a bridge between the receptor and a specific anti-ligand antibody. By this method we have localised receptors for bombesin in cells of small cell lung carcinoma in culture. The results support previous biochemical evidence for the existence of said receptors and the technique should be applicable for the localisation of other receptors recognising small ligands.