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δ‐Opioid receptor binding sites in rodent spinal cord
Author(s) -
Traynor J.R.,
Hunter J.C,
Rodriguez R.E.,
Hill R.G.,
Hughes J.
Publication year - 1990
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1990.tb15802.x
Subject(s) - opioid receptor , spinal cord , enkephalin , opioid , (+) naloxone , agonist , receptor , chemistry , diprenorphine , hamster , pharmacology , nociception , medicine , endocrinology , guinea pig , δ opioid receptor , biology , neuroscience , biochemistry
1 The δ‐opioid receptor agonist [ d ‐P en 2 , d ‐Pe n 5 ]enkephalin showed an antinociceptive effect in the mouse tail‐flick test, following intrathecal administration. This action was reversed by naloxone and by the selective δ‐opioid receptor antagonist ICI 174864. 2 High affinity, saturable binding of [ 3 H]‐[ d ‐P en 2 , d ‐Pe n 5 ]enkephalin has been demonstrated in spinal cord homogenates from guinea‐pig, hamster, rat and both adult and young (18–20 g) mice. The binding was shown by autoradiography to be concentrated in the superficial laminae of the dorsal horn. 3 Competition studies confirmed that the binding of [ 3 H]‐[ d ‐P en 2 , d ‐Pe n 5 ]enkephalin was to the δ‐opioid site. However, anomalies were seen with displacement assays using μ‐ligands, which may suggest some common high affinity site for δ‐ and μ‐opioid receptor agonists in the spinal cord. 4 The results add further evidence for a role of the δ‐opioid receptor in spinally‐mediated antinociception.