(/sup 3/H)-beta-endorphin binding in rat brain

Journal Article · Mon Oct 01 00:00:00 EDT 1984 · J. Neurosci.; (United States)

OSTI ID:5836476

Houghten, R A; Johnson, N; Pasternak, G W

The binding of (/sup 3/H)-beta-endorphin to rat brain homogenates is complex. Although Scatchard analysis of saturation studies yields a straight line, detailed competition studies are multiphasic, suggesting that even at low concentrations of the compound, the /sup 3/H-ligand is binding to more than one class of site. A portion of (/sup 3/H)-beta-endorphin binding is sensitive to low concentrations of morphine or D-Ala2-Leu5-enkephalin (less than 5 nM). The inhibition observed with each compound alone (5 nM) is the same as that seen with both together (each at 5 nM). Thus, the binding remaining in the presence of both morphine and the enkephalin does not correspond to either mu or delta sites. The portion of (/sup 3/H)-beta-endorphin binding that is inhibited under these conditions appears to be equally sensitive to both morphine and the enkephalin and may correspond to mu1 sites. Treating membrane homogenates with naloxonazine, a mu1 selective antagonist, lowers (/sup 3/H)-beta-endorphin binding to the same degree as morphine and D-Ala2-Leu5-enkephalin alone or together. This possible binding of (/sup 3/H)-beta-endorphin to mu1 sites is consistent with the role of mu1 sites in beta-endorphin analgesia and catalepsy in vivo.

• Research Organization: Scripps Clinic and Research Foundation, La Jolla, CA
• OSTI ID: 5836476
• Journal Information: J. Neurosci.; (United States), Vol. 4:10
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
ENDORPHINS
BIOCHEMICAL REACTION KINETICS
BRAIN
ENKEPHALINS
HOMOGENATES
INHIBITION
LIGANDS
MORPHINE
RATS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
ALKALOIDS
ANALGESICS
ANIMALS
AUTONOMIC NERVOUS SYSTEM AGENTS
BODY
CENTRAL NERVOUS SYSTEM
CENTRAL NERVOUS SYSTEM DEPRESSANTS
DRUGS
ISOTOPE APPLICATIONS
KINETICS
LABELLED COMPOUNDS
MAMMALS
NARCOTICS
NERVOUS SYSTEM
NEUROREGULATORS
OPIUM
ORGANIC COMPOUNDS
ORGANS
PEPTIDES
POLYPEPTIDES
PROTEINS
REACTION KINETICS
RODENTS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques