title: Role of protein phosphatases inhibitors on the histamine release and the functional desensitization in human lung mast cells.
abstract: BACKGROUND
  The β2-adrenoceptor agonist, isoprenaline, is an effective inhibitor of histamine release from human lung mast cells (HLMC). Since phosphorylations of the β2-adrenoceptors are probably important in inducing desensitization, we sought to investigate the importance of phosphorylation events by targeting protein phosphatases (PPs) in mast cells. To this end, the effects of the inhibitor of on the functional desensitization of β-adrenoceptor-mediated responses in mast cells were investigated.
  
  
  METHODS
  In this study the effects of PP inhibitors on the inhibition of histamine release from HLMC, on β-agonists in mast cells and on desensitization were investigated.
  
  
  RESULTS
  Long-term exposure of mast cells to both isoprenaline and salbutamol substantially reduced the extent to which isoprenaline inhibited histamine release. Pretreatments of up to 24 h with inhibitors alone had no effect on immunoglobulin E-mediated histamine release. Shorter (≤4 h) pretreatments had little effect on the activity of isoprenaline and salbutamol to inhibit histamine release from mast cells.
  
  
  CONCLUSIONS
  Collectively, these data suggest that PP has an important role in regulating mast cell β2-adrenoceptors.
authors.affiliation: Department of Human Vaccines, Razi Serum and Vaccine Research Institute, Karaj, Iran.
authors.forename: Reza
authors.initials: R
authors.lastname: Bastan
authors.affiliation: Department of Immunology, Faculty of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Nahid
authors.initials: N
authors.lastname: Eskandari
authors.affiliation: Isfahan Clinical Toxicology Research Center, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Ali Mohammad
authors.initials: AM
authors.lastname: Sabzghabaee
authors.affiliation: Department of Immunology, Faculty of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Seyyed Hamid Zarkesh
authors.initials: SH
authors.lastname: Esfahani
authors.affiliation: Department of Immunopharmacology, University of Sheffield, Sheffield, UK.
authors.forename: Peter T
authors.initials: PT
authors.lastname: Peachell
keywords: Desensitization; histamine; mast cell; protein phosphatases; β2-adrenoceptors