title: Autoradiographic mapping of pulmonary NK1 and NK2 tachykinin receptors and changes after repeated antigen challenge in guinea pigs.
abstract: An autoradiographic technique was used to study the distribution of changes in pulmonary NK1 and NK2 receptors in guinea pig lung after repeated antigen challenge. Specific labeling of [3H]CP96345 (NK1 receptors) and [3H]SR48968 (NK2 receptors) was localized over the tracheal and bronchial smooth muscle; the density of binding increased towards smaller airways with a higher density for [3H]CP96345 binding. Bronchial epithelium and pulmonary blood vessels were also labeled densely with [3H]CP96345. No remarkable difference in the pattern of distribution of pulmonary NK1 and NK2 tachykinin receptors was observed between control, vehicle-challenged, and repeatedly antigen-challenged (weekly for three times) guinea pigs. A significant reduction in specific labeling of [3H]CP96345 (p < 0.01) and [3H]SR48968 (p < 0.05) over pulmonary structures was observed in antigen-challenged compared to control or vehicle-challenged animals. This study provides evidence that NK1 and NK2 tachykinin receptors are both localized to smooth muscle of all sizes in guinea pig airways and provides further evidence for a discrete distribution of NK1 and NK2 tachykinin receptors, consistent with their relative functional activities. In an established model of airway inflammation a decrease in the expression of NK1 and NK2 tachykinin receptors was evident on several different cell types within the lung, and this could influence airway and vascular reactivity.
authors.affiliation: Department of Thoracic Medicine, National Heart & Lung Institute, Imperial College, London, UK.
authors.forename: J C
authors.initials: JC
authors.lastname: Mak
authors.forename: M
authors.initials: M
authors.lastname: Astolfi
authors.forename: X L
authors.initials: XL
authors.lastname: Zhang
authors.forename: S
authors.initials: S
authors.lastname: Evangelista
authors.forename: S
authors.initials: S
authors.lastname: Manzini
authors.forename: P J
authors.initials: PJ
authors.lastname: Barnes
mesh_terms: D000818:Animals; D000941:Antigens / Q000008:administration & dosage*; D001345:Autoradiography; D001549:Benzamides / Q000378:metabolism; D001665:Binding Sites; D001713:Biphenyl Compounds / Q000378:metabolism; D006168:Guinea Pigs; D007249:Inflammation / Q000378:metabolism; D008168:Lung / Q000276:immunology* / Q000378:metabolism*; D008297:Male; D064729:Neurokinin-1 Receptor Antagonists; D010047:Ovalbumin / Q000008:administration & dosage / Q000276:immunology; D010880:Piperidines / Q000378:metabolism; D018040:Receptors, Neurokinin-1 / Q000378:metabolism*; D018041:Receptors, Neurokinin-2 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D014018:Tissue Distribution
chemical_list: D000941:Antigens; D001549:Benzamides; D001713:Biphenyl Compounds; D064729:Neurokinin-1 Receptor Antagonists; D010880:Piperidines; D018040:Receptors, Neurokinin-1; D018041:Receptors, Neurokinin-2; C073839:SR 48968; D010047:Ovalbumin; C066892:CP 96345