Pharmacological and molecular properties of opioid binding sites synthesized in a cell‐free translation system

Abstract

Cell-free translation of mRNA, extracted from NG108-15 cells, was used to examine some properties of the opioid binding sites synthesized in vitro. A monoclonal antiidiotype antibody directed against the delta opioid receptor immunoprecipitated a major band of Mr 51,000. Translational immunoassays of poly[A]+RNA, size fractionated by methylmercury agarose gel electrophoresis, demonstrated that the 51,000 Mr protein specifically immunoprecipitated by the anti-opioid receptor antiidiotype antibodies was coded by a transcript which length was in the 6 to 8 kb range. Displacement binding studies of tritiated ligands (either bremazocine or delta or mu selective peptides) with type selective opioid ligands showed that only one type of opioid binding site was synthesized in vitro. Although the pharmacological profiles of ligands binding to NG108-15 cells were characteristic of the delta receptor type, the de novo synthesized opioid binding site had lost its delta selectivity and showed equal affinity for both the mu and delta but not for the kappa ligands. Similar to our finding using the immunoprecipitation system, size fractionation of the NG108-15 poly[A]+RNA demonstrated that the transcript coding for the "mu-delta" binding site had a length of 6,500 to 7,500 nucleotides.

Age‐Dependent Changes in the Subcellular Distribution of Rat Brain μ‐Opioid Receptors and GTP Binding Regulatory Proteins

“…Perhaps the better two-site fit for HMs reflects DAMGE binding to /?-endorphin and enkephalin receptors. Multiple site binding in P1 compared to adult LMs is also consistent with the notion that LMs are enriched in incompletely processed precursors which would be expected to display different affinities for DAMGE (Cabon et al, 1990). Finally, we cannot rule out the possibility that DAMGE is also binding to a neonatal receptor that is either an incompletely processed or fetal isoform of a 6-, K-opioid, or for that matter, some other type of receptor (Barg et al, 1990).…”

Επιδραση Οπιοειδων Στην Εκκριση Του Παραγοντα Απελευθερωσης Των Γοναδοτροπινων (Gnrh) Στον Υποθαλαμο Και Στην Εκκριση Της Ωχρινοποιητικης Ορμονης (Lh) Στην Υποφυση

“…δ-oπuoεuδεύς υποδοχεύς πuστεύετau óτu αποτελούν προ'ύόντα του uôuou Yovuôuou Kau óτu ou ôuacpopéç τους oφεύλovτau σε μετα-μεταφραστχκές τpoπoπouήσεuς( Cabon et al, 1990 ). ομάδα του Evans( Evans et al, 1992 ).…”