title: Pharmacogenomic study of the role of the nociceptin/orphanin FQ receptor and opioid receptors in diabetic hyperalgesia.
abstract: Targeting functionally independent receptors may provide synergistic analgesic effects in neuropathic pain. To examine the interdependency between different opioid receptors (µ-opioid peptide [MOP], δ-opioid peptide [DOP] and κ-opioid peptide [KOP]) and the nociceptin/orphanin FQ peptide (NOP) receptor in streptozotocin (STZ)-induced diabetic polyneuropathy, nocifensive activity was measured using a hot plate test in wild-type and NOP, MOP, DOP and KOP receptor knockout mice in response to the selective receptor agonists Ro65-6570, morphine, SNC-80 and U50488H, or vehicle. Nocifensive activity was similar in non-diabetic wild-type and knockout mice at baseline, before agonist or vehicle administration. STZ-induced diabetes significantly increased heat sensitivity in all mouse strains, but MOP, DOP and KOP receptor knockouts showed a smaller degree of hyperalgesia than wild-type mice and NOP receptor knockouts. For each agonist, a significant antihyperalgesic effect was observed in wild-type diabetic mice (all P<0.05 versus vehicle); the effect was markedly attenuated in diabetic mice lacking the cognate receptor compared with wild-type diabetic mice. Morphine was the only agonist that demonstrated near-full antihyperalgesic efficacy across all non-cognate receptor knockouts. Partial or near-complete reductions in efficacy were observed with Ro65-6570 in DOP and KOP receptor knockouts, with SNC-80 in NOP, MOP and KOP receptor knockouts, and with U50488H in NOP and DOP receptor knockouts. There was no evidence of NOP and MOP receptor interdependency in response to selective agonists for these receptors. These findings suggest that concurrent activation of NOP and MOP receptors, which showed functional independence, may yield an effective and favorable therapeutic analgesic profile.
authors.affiliation: Grünenthal GmbH, Global Preclinical Drug Development, Department of Pain Pharmacology, Zieglerstrasse 6, 52078 Aachen, Germany. Electronic address: kris.rutten@grunenthal.com.
authors.forename: Kris
authors.initials: K
authors.lastname: Rutten
authors.affiliation: Grünenthal GmbH, Global Preclinical Drug Development, Department of Pain Pharmacology, Zieglerstrasse 6, 52078 Aachen, Germany.
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Tzschentke
authors.affiliation: Grünenthal GmbH, Global Preclinical Drug Development, Department of Molecular Pharmacology, Aachen, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Koch
authors.affiliation: Grünenthal GmbH, Global Preclinical Drug Development, Department of Pain Pharmacology, Zieglerstrasse 6, 52078 Aachen, Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Schiene
authors.affiliation: Grünenthal GmbH, Global Preclinical Drug Development, Department of Pain Pharmacology, Zieglerstrasse 6, 52078 Aachen, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Christoph
mesh_terms: D000701:Analgesics, Opioid / Q000494:pharmacology / Q000627:therapeutic use; D000818:Animals; D003921:Diabetes Mellitus, Experimental / Q000188:drug therapy / Q000235:genetics* / Q000378:metabolism*; D006930:Hyperalgesia / Q000188:drug therapy / Q000235:genetics* / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D051381:Rats; D017207:Rats, Sprague-Dawley; D011957:Receptors, Opioid / Q000502:physiology*; D017450:Receptors, Opioid, mu / Q000819:agonists / Q000502:physiology*; D000094942:Nociceptin Receptor
chemical_list: D000701:Analgesics, Opioid; D011957:Receptors, Opioid; D017450:Receptors, Opioid, mu; D000094942:Nociceptin Receptor
keywords: Antihyperalgesia; Knockout mice; Neuropathic pain; Nociceptin/orphanin FQ receptor; ORL1; Opioid receptors