title: Changes in cellular membrane and paracellular conductances by amphotericin B in the epithelium of the bullfrog cornea.
abstract: In the isolated bullfrog cornea, measurements of DC electrical parameters in conjunction with AC impedance and ultrastructural analyses were used to determine the effects of 10(-5) M amphotericin B on epithelial cellular membrane and paracellular conductances. In NaCl Ringers, amphotericin B elicited a 3.5-fold increase in the specific apical membrane conductance (Ga/Ca); where Ga and Ca are the apical membrane conductance and capacitance, respectively. The basolateral membrane conductance (Gb) and the basolateral membrane capacitance (Cb) fell by 57% and 50%, respectively. In the paracellular pathway, the tight junctional complex (Gj) was unchanged whereas the lateral intercellular space resistance (Rp) decreased by 55%. The declines in Gb and Cb were suggestive of cell volume shrinkage because these changes were consistent with a previously described decline in intracellular K+ content and reduction in exposed basolateral membrane area to current flow. Ultrastructural analysis validated that amphotericin B caused cell volume shrinkage because there was: (1) increased folding of the basolateral membrane and waviness of the basal aspects- of the plasma membrane; (2) dilatation of the lateral intercellular spaces. This agreement suggests that intracellular activity decreased following exposure to amphotericin B which resulted in cell volume shrinkage and an impairment of Cl- uptake across the basolateral membrane.
authors.affiliation: Department of Ophthalmology, Washington University School of Medicine, St. Louis, MO.
authors.forename: P S
authors.initials: PS
authors.lastname: Reinach
authors.forename: J T
authors.initials: JT
authors.lastname: Tarvin
authors.forename: M
authors.initials: M
authors.lastname: Hirsch
mesh_terms: D000666:Amphotericin B / Q000494:pharmacology*; D000818:Animals; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D002712:Chlorides / Q000378:metabolism*; D003315:Cornea / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D004553:Electric Conductivity / Q000187:drug effects; D004848:Epithelium / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D005110:Extracellular Space / Q000187:drug effects / Q000378:metabolism; D005614:Freeze Fracturing; D007365:Intercellular Junctions / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D007700:Kinetics; D008854:Microscopy, Electron; D011892:Rana catesbeiana
chemical_list: D002712:Chlorides; D000666:Amphotericin B