The mu-opioid receptor is necessary for [D-Pen2,D-Pen5]enkephalin-induced analgesia.
Interactions between delta-opioid receptors and morphine-preferring mu-opioid receptor subtypes have been suggested. Availability of transgenic mu-opioid receptor knockout mice allows assessment of mu-opioid receptor roles in the analgesia produced by the classical delta-opioid receptor agonist [D-Pen2,D-Pen5]enkephalin (DPDPE) in hot-plate and tail-flick tests. DPDPE analgesia was dramatically reduced in mu-opioid receptor knockout mice in a gene-dose-dependent fashion. The analgesia induced by this classic delta-opioid receptor agonist depends on intact mu-opioid receptors, suggesting that selective delta-opioid receptor drugs may require mu-opioid receptor occupancies for full efficacy.
Sora
I
I
Molecular Neurobiology Branch, National Institute on Drug Abuse-IRP, Baltimore, MD 21224, USA.
Funada
M
M
Uhl
G R
GR
D000698:Analgesia; D000700:Analgesics; D000818:Animals; D020881:Enkephalin, D-Penicillamine (2,5)-; D004745:Enkephalins; D051379:Mice; D018345:Mice, Knockout; D008822:Mice, Transgenic; D017450:Receptors, Opioid, mu / Q000819:agonists / Q000235:genetics / Q000378:metabolism*
D000700:Analgesics; D004745:Enkephalins; D017450:Receptors, Opioid, mu; D020881:Enkephalin, D-Penicillamine (2,5)-