title: Expression of nitric oxide synthase type II in the spinal cord under conditions producing thermal hyperalgesia.
abstract: There is evidence supporting spinal cord nitric oxide (NO) production in the mechanisms underlying hyperalgesia, presumed to arise from the activity of neuronal nitric oxide synthase type I (NOS I). Intrathecal administration of interleukin-1 beta and interferon-gamma to rats results in a thermal hyperalgesia which peaks at 2 h post-injection but which is undetectable 8 h post-injection. Expression of mRNA for nitric oxide synthase type II (NOS II) was detected by reverse transcription-polymerase chain reaction followed by Southern hybridization utilizing specific oligonucleotides in spinal cord tissue from animals 4 h and 8 h after cytokine injection, but not at longer time points. NOS II protein was detected in soluble fractions of spinal cords from animals 4 h and 8 h after cytokine injection. In situ hybridization for NOS II mRNA revealed positive cells bilaterally in the spinal cord 4 h after cytokine injection in a perivascular distribution and scattered throughout the gray and white matter. Immunohistochemistry for NOS II showed a similar distribution which could only be partially accounted for by macrophages/microglia. These results provide evidence for induction of NOS II expression under conditions producing thermal hyperalgesia and suggest a possible role in this behavior for the production of NO by a variety of cell types in the CNS.
authors.affiliation: Department of Pathology, University of Iowa College of Medicine, Iowa City 52242, USA.
authors.forename: D
authors.initials: D
authors.lastname: Grzybicki
authors.forename: G F
authors.initials: GF
authors.lastname: Gebhart
authors.forename: S
authors.initials: S
authors.lastname: Murphy
mesh_terms: D000818:Animals; D015139:Blotting, Southern; D015153:Blotting, Western; D002460:Cell Line / Q000502:physiology; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology; D006358:Hot Temperature; D006930:Hyperalgesia / Q000201:enzymology* / Q000503:physiopathology; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008264:Macrophages / Q000166:cytology; D009474:Neurons / Q000737:chemistry / Q000201:enzymology; D019001:Nitric Oxide Synthase / Q000235:genetics* / Q000378:metabolism; D009619:Nociceptors / Q000502:physiology; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013116:Spinal Cord / Q000166:cytology / Q000201:enzymology* / Q000502:physiology
chemical_list: D012333:RNA, Messenger; D019001:Nitric Oxide Synthase