title: Omeprazole decreases magnesium transport across Caco-2 monolayers.
abstract: OBJECTIVE
  To elucidate the effect and underlying mechanisms of omeprazole action on Mg(2+) transport across the intestinal epithelium.
  
  
  METHODS
  Caco-2 monolayers were cultured in various dose omeprazole-containing media for 14 or 21 d before being inserted into a modified Ussing chamber apparatus to investigate the bi-directional Mg(2+) transport and electrical parameters. Paracellular permeability of the monolayer was also observed by the dilution potential technique and a cation permeability study. An Arrhenius plot was performed to elucidate the activation energy of passive Mg(2+) transport across the Caco-2 monolayers.
  
  
  RESULTS
  Both apical to basolateral and basolateral to apical passive Mg(2+) fluxes of omeprazole-treated epithelium were decreased in a dose- and time-dependent manner. Omeprazole also decreased the paracellular cation selectivity and changed the paracellular selective permeability profile of Caco-2 epithelium to Li(+), Na(+), K(+), Rb(+), and Cs(+) from series VII to series VI of the Eisenman sequence. The Arrhenius plot revealed the higher activation energy for passive Mg(2+) transport in omeprazole-treated epithelium than that of control epithelium, indicating that omeprazole affected the paracellular channel of Caco-2 epithelium in such a way that Mg(2+) movement was impeded.
  
  
  CONCLUSIONS
  Omeprazole decreased paracellular cation permeability and increased the activation energy for passive Mg(2+) transport of Caco-2 monolayers that led to the suppression of passive Mg(2+) absorption.
authors.affiliation: Faculty of Allied Health Sciences, Burapha University, Chonburi 20131, Thailand. narongritt@buu.ac.th
authors.forename: Narongrit
authors.initials: N
authors.lastname: Thongon
authors.forename: Nateetip
authors.initials: N
authors.lastname: Krishnamra
mesh_terms: D000704:Analysis of Variance; D001692:Biological Transport; D018938:Caco-2 Cells; D004305:Dose-Response Relationship, Drug; D017097:Electric Impedance; D006801:Humans; D007408:Intestinal Absorption / Q000187:drug effects*; D007413:Intestinal Mucosa / Q000187:drug effects* / Q000378:metabolism; D007700:Kinetics; D016014:Linear Models; D015636:Magnesium Chloride / Q000378:metabolism*; D008954:Models, Biological; D009853:Omeprazole / Q000494:pharmacology*; D010539:Permeability; D054328:Proton Pump Inhibitors / Q000494:pharmacology*
chemical_list: D054328:Proton Pump Inhibitors; D015636:Magnesium Chloride; D009853:Omeprazole