title: Cyclosporine reduces basolateral, but not apical, nitric oxide secretion in medullary thick ascending limb cells.
abstract: Cyclosporine (CsA) reduces nitric oxide (NO) production in medullary thick ascending limb (mTAL) cells. We postulated that CsA affected NO secretion in a vectorial manner in polarized renal epithelial cells. The experiments were performed in a model of mTAL subcultured cells. The expression of iNOS in mTAL cells was confirmed by RT-PCR. The cells were grown on a non-permeable filter. Nitrite was measured by the modified Griess method. Transepithelial resistance was measured to ensure the integrity of the tight junction. CsA (100 ng/ml) reduced NO production by 22% in mTAL cells. The inhibitory effect was limited to the basolateral side (control: 165 +/- 11; plus CsA: 93 +/- 17 nM/10(6) cells, P < 0.001) without affecting apical NO secretion. The transepithelial resistance through the epithelial monolayer remained unchanged in CsA-treated cells. CsA reduced basolateral NO secretion without affecting apical secretion. The results suggest that CsA might affect intrarenal hemodynamics at the peritubular level.
authors: Division of Nephrology, Chang Gung Memorial Hospital, Taipei, Taiwan. maisuwu@ms9.hinet.net
authors: M S
authors: MS
authors: Wu
authors: M
authors: M
authors: Bens
authors: H M
authors: HM
authors: Yu
authors: A
authors: A
authors: Vandewalle
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D016572:Cyclosporine / Q000494:pharmacology*; D007679:Kidney Medulla / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D008138:Loop of Henle / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D051379:Mice; D009569:Nitric Oxide / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000235:genetics*; D052247:Nitric Oxide Synthase Type II; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019108:Tight Junctions / Q000187:drug effects / Q000502:physiology
chemical_list: D009569:Nitric Oxide; D016572:Cyclosporine; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse