/sup 125/I-FK 33-824: a selective probe for radioautographic labeling of mu opioid receptors in the brain

Journal Article · Sat Mar 01 00:00:00 EST 1986 · Peptides (Fayetteville, N.Y.); (United States)

DOI:https://doi.org/10.1016/0196-9781(86)90235-4· OSTI ID:5126040

Moyse, E; Pasquini, F; Quirion, R; Beaudet, A

The selectivity of the Met-enkephalin analog FK 33-824 (FK) for mu opioid receptors has been, over the years, a matter of controversy. We report here pharmacological and radioautographic data demonstrating that at nanomolar concentrations. /sup 125/I-FK interacts exclusively with mu sites. (1) Specific binding of /sup 125/I-FK to rat striatal membranes is totally inhibited by mu- and/or delta-preferring ligands according to monovalent, Michaelian kinetics, with a potency proportional to the affinity of competing drugs for mu receptors. (2) Unlabeled FK competes only at high concentration with the delta-selective ligand 3H-DPLPE and according to the same kinetics as the mu-selective agonist DAGO. (3) /sup 125/I-FK generates the same regional radioautographic labeling pattern as 3H-DAGO. We conclude that when used at nanomolar concentrations /sup 125/I-FK constitutes a selective probe for the radioautographic detection of mu opioid receptors at both light and electron microscopic levels.

• Research Organization: Montreal Neurological Institute, Quebec
• OSTI ID: 5126040
• Journal Information: Peptides (Fayetteville, N.Y.); (United States), Vol. 2
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
BRAIN
AUTORADIOGRAPHY
ENKEPHALINS
RADIORECEPTOR ASSAY
OPIUM
BIOCHEMICAL REACTION KINETICS
CELL MEMBRANES
COMPETITION
IODINE 125
LABELLED COMPOUNDS
RATS
RECEPTORS
ANALGESICS
ANIMALS
AUTONOMIC NERVOUS SYSTEM AGENTS
BETA DECAY RADIOISOTOPES
BODY
CELL CONSTITUENTS
CENTRAL NERVOUS SYSTEM
CENTRAL NERVOUS SYSTEM DEPRESSANTS
DAYS LIVING RADIOISOTOPES
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
ENDORPHINS
INTERMEDIATE MASS NUCLEI
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
MAMMALS
MEMBRANE PROTEINS
MEMBRANES
NARCOTICS
NERVOUS SYSTEM
NEUROREGULATORS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANS
PEPTIDES
POLYPEPTIDES
PROTEINS
RADIOISOTOPES
REACTION KINETICS
RODENTS
TRACER TECHNIQUES
VERTEBRATES
550201* - Biochemistry- Tracer Techniques