title: Regulation of paracellular ion conductances by NaCl gradients in renal epithelial cells.
abstract: In the present study, we clarified how the NaCl gradient across the epithelial cells regulates the paracellular ion conductance. Under isotonic conditions, the absorption-directed NaCl gradient elevated the paracellular conductances of Na(+) (G(Na)) and Cl(-) (G(Cl)), while the secretion-directed NaCl gradient diminished the G(Na) and G(Cl). We further investigated the paracellular ionic conductances of NMDG (G(NMDG)) and gluconate (G(gluconate)) by replacing Na(+) with NMDG or Cl(-) with gluconate. The G(NMDG) was lower than the G(Na) and the replacement of Na(+) with NMDG decreased the G(Cl). The G(gluconate) was lower than the G(Cl) and the replacement of Cl(-) with gluconate also decreased the G(Na). These observations suggest the interaction of cations and anions on paracellular ionic conductances; i.e., cations affect paracellular anion conductances and anions affect paracellular cation conductances.
authors: Department of Molecular Cell Physiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan.
authors: Shinsaku
authors: S
authors: Tokuda
authors: Naomi
authors: N
authors: Niisato
authors: Yoshinori
authors: Y
authors: Marunaka
mesh_terms: D000465:Algorithms; D000584:Amiloride / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D017609:Barium Compounds / Q000494:pharmacology; D002460:Cell Line; D018118:Chloride Channels / Q000037:antagonists & inhibitors; D002712:Chlorides / Q000378:metabolism / Q000494:pharmacology; D004553:Electric Conductivity; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D017136:Ion Transport / Q000187:drug effects; D007668:Kidney / Q000166:cytology; D008564:Membrane Potentials / Q000187:drug effects; D009579:Nitrobenzoates / Q000494:pharmacology; D011188:Potassium / Q000378:metabolism; D026902:Potassium Channel Blockers / Q000494:pharmacology; D012964:Sodium / Q000378:metabolism; D012965:Sodium Chloride / Q000494:pharmacology*; D013997:Time Factors
chemical_list: D017609:Barium Compounds; D018118:Chloride Channels; D002712:Chlorides; D009579:Nitrobenzoates; D026902:Potassium Channel Blockers; C013407:benzamil; C024986:barium chloride; C058176:5-nitro-2-(3-phenylpropylamino)benzoic acid; D012965:Sodium Chloride; D000584:Amiloride; D012964:Sodium; D011188:Potassium