title: Expression and localization of histamine H2 receptor messenger RNA in human nasal mucosa.
abstract: BACKGROUND
  Histamine is an important chemical mediator in allergic rhinitis. Histamine H2 receptor (H2R) stimulation controls histamine release and mediates mucus secretion, suggesting that H2R might play some role in allergic rhinitis.
  
  
  OBJECTIVE
  The objective of this study was to examine whether H2R mRNA expression is increased in patients with allergic rhinitis compared with normal subjects and to determine the localization of H2R mRNA in the human nasal mucosa.
  
  
  METHODS
  We extracted RNA from scrapings of the inferior turbinate mucosa of 11 patients with allergic rhinitis. H2R and beta-actin mRNA were amplified by RT-PCR. In situ hybridization with a digoxigenin-labeled H2R cRNA probe was performed on surgical specimens of nasal turbinate of patients with allergic rhinitis.
  
  
  RESULTS
  The mean +/- SD of H2R/beta-actin ratios were 0.12 +/- 0.16 for the scrapings of normal subjects and 0.35 +/- 0.20 for the scrapings of patients with allergic rhinitis; the difference was statistically significant (P <.01). H2R mRNA was localized in the epithelium, serous cells, and mucous cells.
  
  
  CONCLUSIONS
  These data suggest that H2R mRNA is localized in the epithelium and the submucosal glands and that increased H2R may be playing some role in patients with allergic rhinitis.
mesh_terms: D000199:Actins / Q000235:genetics; D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D017403:In Situ Hybridization; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D009297:Nasal Mucosa / Q000737:chemistry*; D012326:RNA Splicing; D012333:RNA, Messenger / Q000302:isolation & purification* / Q000378:metabolism*; D011970:Receptors, Histamine H2 / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012221:Rhinitis, Allergic, Perennial / Q000276:immunology / Q000601:surgery; D006255:Rhinitis, Allergic, Seasonal / Q000276:immunology / Q000601:surgery