TECHNICAL ASPECTS OF OPIOID RECEPTOR LOCALIZATION - DETECTION OF OPIOID RECEPTOR PROTEINS BY IMMUNOCYTOCHEMISTRY OR WITH A BIOTINYLATED DYNORPHIN ANALOG

Opioid receptors were localized at the cellular level, using either an ti-opioid receptor antibodies or a biotinylated opioid ligand. In addi tion, a simple method was developed for selection of second antisera o n their potencies to detect particular monoclonal antibodies (mAbs). M ost anti-opioid receptor antibodies tested were not able to recognize the opioid receptor in frozen or fixed tissue sections, which was in c ontrast with their ability to recognize opioid receptors in isolated m embrane fractions. However, one batch of anti-idiotypic mAbs gave a go od immunocytochemical staining. Distribution of immunoreactivity sugge sted that these antibodies recognized more than one opioid receptor su btype. After very short fixation times, staining with a biotinylated k appa-selective ligand (DAKLIB) could be observed in the neural and int ermediate lobe of pituitary. This binding could be displaced by non-bi otinylated DAKLI. The pattern of DAKLIB staining in the neural lobe ha d the appearance of binding to both nerve fibres and astrocytes. The p resent results show successful staining of tissue sections with anti-i diotypic antibodies and with a biotinylated ligand. The specificity is discussed in the light of control experiments, pharmacological data a nd previous studies.