Biphasic competition between opiates and enkephalins: does it indicate the existence of a common high affinity (mu-1) binding site
Journal Article
·
· Life Sci.; (United States)
Displacement from brain membranes of labeled opiates by low concentrations of enkephalins and of labeled enkephalins by low concentrations of opiates has been previously explained by the existance of a common high affinity site termed mu-1. An alternative interpretation of the same results is that the trough seen in the low concentration zone of the displacement curves represents cross binding of mu and delta opioid ligands to delta and mu receptors, respectively. In three sets of experiments with brain membranes, the size of the trough is shown to be dependent on the labeled ligand used: The ratio between the size of troughs seen with (TH)D-Ala, D-Leu enkephalin and with (TH)morphine varies with experimental conditions (storage of membranes at 4C for 72h), with ratio of mu:delta receptors (e.g. in thalamus and cortex which are enriched in mu and delta sites, respectively) and with pretreatment of membranes with naloxonazine. These results cannot be explained by a common high affinity site, but rather by binding of (TH)D-Ala, D-Leu enkephalin to mu and of (TH)morphine to delta opioid receptors. 17 references, 3 figures.
- Research Organization:
- Tel Aviv Univ., Israel
- OSTI ID:
- 6360462
- Journal Information:
- Life Sci.; (United States), Journal Name: Life Sci.; (United States) Vol. 41:5; ISSN LIFSA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AFFINITY
ALKALOIDS
ANALGESICS
AUTONOMIC NERVOUS SYSTEM AGENTS
BIOCHEMICAL REACTION KINETICS
BODY
BRAIN
CELL CONSTITUENTS
CELL MEMBRANES
CENTRAL NERVOUS SYSTEM
CENTRAL NERVOUS SYSTEM DEPRESSANTS
DATA
DRUGS
ENDORPHINS
ENKEPHALINS
EXPERIMENTAL DATA
INFORMATION
ISOTOPE APPLICATIONS
KINETICS
LABELLED COMPOUNDS
LIGANDS
MEMBRANES
MORPHINE
NARCOTICS
NERVOUS SYSTEM
NEUROREGULATORS
NUMERICAL DATA
OPIUM
ORGANIC COMPOUNDS
ORGANS
PEPTIDES
POLYPEPTIDES
PROTEINS
REACTION KINETICS
RECEPTORS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
59 BASIC BIOLOGICAL SCIENCES
AFFINITY
ALKALOIDS
ANALGESICS
AUTONOMIC NERVOUS SYSTEM AGENTS
BIOCHEMICAL REACTION KINETICS
BODY
BRAIN
CELL CONSTITUENTS
CELL MEMBRANES
CENTRAL NERVOUS SYSTEM
CENTRAL NERVOUS SYSTEM DEPRESSANTS
DATA
DRUGS
ENDORPHINS
ENKEPHALINS
EXPERIMENTAL DATA
INFORMATION
ISOTOPE APPLICATIONS
KINETICS
LABELLED COMPOUNDS
LIGANDS
MEMBRANES
MORPHINE
NARCOTICS
NERVOUS SYSTEM
NEUROREGULATORS
NUMERICAL DATA
OPIUM
ORGANIC COMPOUNDS
ORGANS
PEPTIDES
POLYPEPTIDES
PROTEINS
REACTION KINETICS
RECEPTORS
TRACER TECHNIQUES
TRITIUM COMPOUNDS