Fourteen. beta. -(bromoacetamido)morphine irreversibly labels. mu. opioid receptors in rat brain membranes

Journal Article · Tue May 16 00:00:00 EDT 1989 · Biochemistry; (USA)

DOI:https://doi.org/10.1021/bi00436a031· OSTI ID:5443515

Bidlack, J M; Frey, D K; Seyed-Mozaffari, A; Archer, S ^[1]

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1. Univ. of Rochester School of Medicine and Dentistry, NY (USA)

The binding properties of 14{beta}-(bromoacetamido)morphine (BAM) and the ability of BAM to irreversibly inhibit opioid binding to rat brain membranes were examined to characterize the affinity and selectivity of BAM as an irreversible affinity ligand for opioid receptors. BAM had the same receptor selectivity as morphine, with a 3-5-fold decrease in affinity for the different types of opioid receptors. When brain membranes were incubated with BAM, followed by extensive washing, opioid binding was restored to control levels. However, when membranes were incubated with dithiothreitol (DTT), followed by BAM, and subsequently washed, 90% of the 0.25 nM ({sup 3}H)(D-Ala{sup 2},(Me)Phe{sup 4},Gly(ol){sup 5})enkephalin (DAGO) binding was irreversibly inhibited as a result of the specific alkylation of a sulfhydryl group at the {mu} binding site. This inhibition was dependent on the concentrations of both DTT and BAM. The {mu} receptor specificity of BAM alkylation was demonstrated by the ability of BAM alkylated membranes to still bind the {delta}-selective peptide ({sup 3}H)(D-penicillamine{sup 2},D-penicillamine{sup 5})enkephalin (DPDPE) and (-)-({sup 3}H)bremazocine in the presence of {mu} and {delta} blockers, selective for {kappa} binding sites. Morphine and naloxone partially protected the binding site from alkylation with BAM, while ligands that did not bind to the {mu}s site did not afford protection. These studies have demonstrated that when a disulfide bond at or near {mu} opioid binding sites was reduced, BAM could then alkylate this site, resulting in the specific irreversible labeling of {mu} opioid receptors.

• OSTI ID: 5443515
• Journal Information: Biochemistry; (USA), Vol. 28:10; ISSN 0006-2960
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
CENTRAL NERVOUS SYSTEM DEPRESSANTS
PHARMACOLOGY
MORPHINE
CROSS-LINKING
RECEPTORS
ALKYLATION
BRAIN
CELL MEMBRANES
CHEMICAL BONDS
IODINE 125
LIGANDS
TRITIUM COMPOUNDS
ALKALOIDS
ANALGESICS
BETA DECAY RADIOISOTOPES
BODY
CELL CONSTITUENTS
CENTRAL NERVOUS SYSTEM
CHEMICAL REACTIONS
DAYS LIVING RADIOISOTOPES
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
HYDROGEN COMPOUNDS
INTERMEDIATE MASS NUCLEI
IODINE ISOTOPES
ISOTOPES
MEMBRANE PROTEINS
MEMBRANES
NARCOTICS
NERVOUS SYSTEM
NUCLEI
ODD-EVEN NUCLEI
OPIUM
ORGANIC COMPOUNDS
ORGANS
POLYMERIZATION
PROTEINS
RADIOISOTOPES
550201* - Biochemistry- Tracer Techniques