title: The significance of chloride in the inhibitory action of disodium cromoglycate on immunologically-stimulated rat peritoneal mast cells.
abstract: BACKGROUND
  The microelectrode array (MEA) was used to investigate the pharmacological relevance of chloride (Cl-) ions in antigen-dependent mast cell activation and the inhibitory effect of disodium cromoglycate (DSCG) on mast cell activation.
  
  
  METHODS
  The movements of ions across the cellular membrane and the potential relationship between Cl- channels and DSCG during immunological activation were investigated using the MEA. The results were then subsequently compared with the amount of histamine released from anti-IgE activated peritoneal mast cells.
  
  
  RESULTS
  The inclusion of charybdotoxin (ChTX) in Cl--free buffer showed that the measured field potentials during antigen-stimulated peritoneal mast cell were a combination of Cl- influx and K+ efflux. The delayed onset time of Cl- influx indicated the presence of a delayed outwardly-rectifying Cl- current in the antigen-stimulated peritoneal mast cells. The use of 5-nitro-2-(3-phenylpropylamino) benzoic acid demonstrated that the activated mast cell membrane potential can be stabilised, thereby reducing the amount of histamine released from the anti-IgE activated mast cells. The correlation between the results of the histamine release assay and the electrophysiological measurements demonstrated the importance of Cl- to anti-IgE dependent mast cell activation. The inhibitory effect of DSCG on anti-IgE activated cells, however, did not correlate with the presumed influx of Cl-.
  
  
  CONCLUSIONS
  The MEA data suggest that Cl- influx is crucial to IgE-dependent mast cell degranulation.
  
  
  CONCLUSIONS
  While the MEA cannot yield information about single channel properties, it is convenient to use and can provide information on the global changes in electrophysiological responses of non-excitable cells.
authors.affiliation: Bioengineering Graduate Programme, The Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Hong Kong.
authors.forename: J K Y
authors.initials: JK
authors.lastname: Law
authors.forename: C K
authors.initials: CK
authors.lastname: Yeung
authors.forename: S P
authors.initials: SP
authors.lastname: Wan
authors.forename: S
authors.initials: S
authors.lastname: Ingebrandt
authors.forename: H Y A
authors.initials: HY
authors.lastname: Lau
authors.forename: J A
authors.initials: JA
authors.lastname: Rudd
authors.forename: M
authors.initials: M
authors.lastname: Chan
mesh_terms: D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000494:pharmacology; D018999:Charybdotoxin / Q000494:pharmacology; D018118:Chloride Channels / Q000187:drug effects / Q000378:metabolism; D002712:Chlorides / Q000494:pharmacology*; D004205:Cromolyn Sodium / Q000494:pharmacology*; D006636:Histamine Release / Q000235:genetics; D008297:Male; D008407:Mast Cells / Q000187:drug effects* / Q000276:immunology*; D008839:Microelectrodes; D009579:Nitrobenzoates / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D017455:Receptors, IgE / Q000187:drug effects / Q000502:physiology*
chemical_list: D000888:Antibodies, Anti-Idiotypic; D018118:Chloride Channels; D002712:Chlorides; C553474:FCER1A protein, rat; D009579:Nitrobenzoates; D017455:Receptors, IgE; C026408:anti-IgE antibodies; D018999:Charybdotoxin; C058176:5-nitro-2-(3-phenylpropylamino)benzoic acid; D004205:Cromolyn Sodium