title: Spinal cord dynorphin may modulate nociception via a kappa-opioid receptor in chronic arthritic rats.
abstract: Inoculation of rats with Mycobacterium butyricum produced an arthritis of the limbs which revealed an enhanced sensitivity to noxious mechanical pressure (hyperalgesia). Arthritic rats displayed a pronounced rise in immunoreactive dynorphin in lumbo-sacral spinal cord which correlated both with the intensity and time-course of this hyperalgesia. MR-2266, a relatively preferential antagonist at the chi-opioid receptor (at which dynorphin is considered to act) potentiated this hyperalgesia. In contrast, MR 2267 (its inactive stereo-isomer) was ineffective. Further, naloxone (a weak chi-antagonist), and ICI 154,129 (a preferential delta-antagonist) were, in each case, inactive. The data demonstrate a pronounced response of spinal dynorphin to chronic arthritic pain in the rat. In addition, they raise the possibility of a function of spinal DYN, via a chi-receptor, in the modulation of chronic arthritic pain.
authors.forename: M J
authors.initials: MJ
authors.lastname: Millan
authors.forename: M H
authors.initials: MH
authors.lastname: Millan
authors.forename: C W
authors.initials: CW
authors.lastname: Pilcher
authors.forename: A
authors.initials: A
authors.lastname: Członkowski
authors.forename: A
authors.initials: A
authors.lastname: Herz
authors.forename: F C
authors.initials: FC
authors.lastname: Colpaert
mesh_terms: D000818:Animals; D001168:Arthritis / Q000378:metabolism / Q000503:physiopathology*; D002908:Chronic Disease; D003214:Conditioning, Classical / Q000187:drug effects; D004399:Dynorphins / Q000378:metabolism*; D004744:Enkephalin, Methionine / Q000032:analysis; D009164:Mycobacterium Infections / Q000378:metabolism / Q000503:physiopathology; D009270:Naloxone / Q000494:pharmacology; D009619:Nociceptors / Q000502:physiology*; D010146:Pain / Q000503:physiopathology; D011863:Radioimmunoassay; D051381:Rats; D011957:Receptors, Opioid / Q000502:physiology*; D017473:Receptors, Opioid, kappa; D013116:Spinal Cord / Q000378:metabolism*
chemical_list: D011957:Receptors, Opioid; D017473:Receptors, Opioid, kappa; D009270:Naloxone; D004744:Enkephalin, Methionine; D004399:Dynorphins