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[3H]Diprenorphine Binding to k ‐Sites in Guinea‐Pig and Rat Brain: Evidence for Apparent Heterogeneity
Author(s) -
Wood M. S.,
Traynor J. R.
Publication year - 1989
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1989.tb07310.x
Subject(s) - diprenorphine , (+) naloxone , guinea pig , opioid antagonist , antagonist , chemistry , binding site , opioid receptor , stereochemistry , receptor , opioid , biophysics , biochemistry , biology , endocrinology
The binding of the unselective opioid antagonist [3H]diprenorphine to homogenates prepared from rat brain and from guinea‐pig brain and cerebellum has been studied in HEPES buffer containing 10 m M Mg2+ ions. Sequential displacement of bound [3H]diprenorphine by ligands with selectivity for μ‐, 8‐ δ, and k ‐opioid receptors uncovers the multiple components of binding. In the presence of cold ligands that occupy all μ‐, δ‐, and k ‐sites, opioid binding still remains. This binding represents 20% of total specific sites and is displaced by naloxone. The nature of these undefined opioid binding sites is discussed.