title: Effect of ibuprofen and rofecoxib transport parameters in the frog corneal epithelium.
abstract: Effects of cyclooxygenase (COX) inhibitors on transport parameters of the frog corneal epithelium were studied. Epithelial cells of the intact cornea were impaled with microelectrodes. Under short-circuit current (I(sc)) conditions, 10(-4) M ibuprofen (IBU) (non-specific COX inhibitor) or 5 x 10(-5) M rofecoxib (COX-2 inhibitor) were added to the tear solution. With ibuprofen, I(sc) decreased by 1.0 from 3.1 microA/cm2; intracellular potential, V(o), depolarized by 14.2 from -56.9 mV; IBU did not affect the transepithelial conductance, g(t), or the apical membrane fractional resistance, fR(o). With rofecoxib, I(sc) decreased by 0.9 from 4.3 microA/cm2; V(o) depolarized by 18 from -62.4 mV; g(t) significantly increased by 0.03 from 0.37 ms/cm2; and fR(o) decreased by 12 from 50. Basolateral membrane K+ and apical membrane Cl- partial conductances were studied by the ion substitution method. Depolarization of V(o) by an increase in stromal K+ from 4 to 79 mM was smaller with IBU (17.5 mV) or rofecoxib (19.2 mV) than without the inhibitors (29.1 and 29.3 mV, respectively). Depolarization of V(o), by a decrease in tear Cl- from 81 to 8.1 mM, was abolished by the COX inhibitors. Decrease in I(sc) and V(o) can be explained by a decrease in the K+ and Cl-? conductances. Experiments with amphotericin B ruled out a major effect of the inhibitors on the Na+/K+ ATPase pump.
authors.affiliation: Department of Medicine (Nephrology), University of Louisville, Louisville, KY 40292, USA. g0carr01@louisville.edu
authors.forename: G
authors.initials: G
authors.lastname: Carrasquer
authors.forename: M
authors.initials: M
authors.lastname: Li
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D019573:Epithelium, Corneal / Q000187:drug effects* / Q000502:physiology*; D007052:Ibuprofen / Q000008:administration & dosage*; D066298:In Vitro Techniques; D007783:Lactones / Q000008:administration & dosage*; D008564:Membrane Potentials / Q000187:drug effects* / Q000502:physiology*; D011892:Rana catesbeiana; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013450:Sulfones
chemical_list: D007783:Lactones; D013450:Sulfones; C116926:rofecoxib; D007052:Ibuprofen