title: [Localization of the neurokinin 1 receptor in hip joints of patients with painful osteoarthritis].
abstract: BACKGROUND
  Recent studies on osteoarthritis have focused on nociceptive substance P (SP) containing afferent nerve fibres. The effects of SP are known to be mainly mediated by the tachykinin receptor neurokinin 1 (NK1-R).
  
  
  OBJECTIVE
  The aim of the present study was to demonstrate the NK1-R in human joint tissues.
  
  
  METHODS
  The hip joint capsule of three patients with painful hip osteoarthritis (Group 1), three patients with femoral neck fracture showing no cartilage destruction (Group 2, controls) and the soft tissue of the fossa acetabuli of Group 1 were resected during hip arthroplasty implantation. The tissue samples were cut into small blocks and immersion-fixed in Zamboni's fixative. The specimens were frozen, cut into 50 microm sections and immunostained using a standard immunohistochemical staining protocol.
  
  
  RESULTS
  In Groups 1 and 2 the NK1-receptor was localised in the wall of venous vessels, on Schwann cells of nerve bundles and on nerve fibres. In the osteoarthritis group the staining pattern was similar but the number of NK1-bearing cell structures seemed to be enhanced.
  
  
  CONCLUSIONS
  The present study provides the first evidence of NK1-R in the human hip joint. In patients with painful osteoarthritis the density of NK1-R-positive cell structures seemed to be increased. The localisation of the NK1 receptor on different cell types suggests multiple effects of SP in normal and osteoarthritic joints.
authors.affiliation: Klinik und Poliklinik für Orthopädie, Universität Duisburg-Essen, Essen. guido.saxler@uni-essen.de
authors.forename: G
authors.initials: G
authors.lastname: Saxler
authors.forename: F
authors.initials: F
authors.lastname: Löer
authors.forename: M
authors.initials: M
authors.lastname: von Knoch
authors.forename: F
authors.initials: F
authors.lastname: von Knoch
authors.forename: U
authors.initials: U
authors.lastname: Hanesch
mesh_terms: D000077:Acetabulum / Q000294:innervation; D000368:Aged; D002358:Cartilage, Articular / Q000294:innervation; D005260:Female; D005265:Femoral Neck Fractures / Q000473:pathology; D006621:Hip Joint / Q000294:innervation; D006801:Humans; D007124:Immunoenzyme Techniques; D017746:Joint Capsule / Q000294:innervation; D009412:Nerve Fibers / Q000473:pathology; D015207:Osteoarthritis, Hip / Q000473:pathology*; D010525:Peripheral Nerves / Q000473:pathology; D018040:Receptors, Neurokinin-1 / Q000032:analysis*; D013373:Substance P / Q000502:physiology; D014699:Venules / Q000294:innervation
chemical_list: D018040:Receptors, Neurokinin-1; D013373:Substance P