Anti-hyperalgesic and anti-allodynic effects of intrathecal nociceptin/orphanin FQ in rats after spinal cord injury, peripheral nerve injury and inflammation.
We examined the effects of intrathecal nociceptin, the endogenous ligand for the orphan opioid receptor-like receptor, on abnormal pain-related behaviors in rats after carrageenan-induced inflammation and photochemically-induced peripheral nerve or spinal cord ischemic injury. Intrathecal nociceptin dose-dependently alleviated mechanical and cold allodynia-like behavior in the two models of neuropathic pain. The heat hyperalgesia associated with peripheral inflammation was also significantly reduced, although the efficacy of the antihyperalgesic effect of nociceptin in the inflammation model was decreased. Intrathecal nociceptin also induced significant antinociception on the tail-flick test in all three groups of rats. However, the antinociceptive effect of nociceptin was significantly reduced in rats with peripheral nerve injury. These results indicated that spinally administered nociceptin has anti-allodynic and anti-hyperalgesic effects in animal models of tonic or chronic pain of different origins. Peripheral inflammation and nerve injury may induce spinal plasticity which leads to altered potency and efficacy of nociceptin.
Hao
Jing-Xia
JX
Department of Medical Laboratory Sciences and Technology, Division of Clinical Neurophysiology, Karolinska Institute, Huddinge University Hospital, Huddinge, Sweden.
Xu
Isabella S
IS
Wiesenfeld-Hallin
Zsuzsanna
Z
Xu
Xiao-Jun
XJ
D000700:Analgesics / Q000008:administration & dosage / Q000627:therapeutic use*; D000701:Analgesics, Opioid / Q000627:therapeutic use; D000818:Animals; D002351:Carrageenan; D003080:Cold Temperature; D004305:Dose-Response Relationship, Drug; D005260:Female; D006358:Hot Temperature; D006930:Hyperalgesia / Q000188:drug therapy* / Q000209:etiology; D007249:Inflammation / Q000139:chemically induced*; D007278:Injections, Spinal; D008297:Male; D009020:Morphine / Q000627:therapeutic use; D018847:Opioid Peptides / Q000008:administration & dosage / Q000627:therapeutic use*; D010147:Pain Measurement / Q000187:drug effects; D059348:Peripheral Nerve Injuries; D010525:Peripheral Nerves / Q000528:radiation effects; D010812:Physical Stimulation; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time / Q000187:drug effects; D012867:Skin / Q000187:drug effects / Q000503:physiopathology; D013119:Spinal Cord Injuries / Q000150:complications*; D000097629:Nociceptin
D000700:Analgesics; D000701:Analgesics, Opioid; D002351:Carrageenan; D009020:Morphine; D018847:Opioid Peptides; D000097629:Nociceptin