Furosemide-sensitive Cl transport in bovine retinal pigment epithelium.
Bovine retinal pigment epithelium (RPE)-choroid explants were sealed in an Ussing chamber. Typical preparations produced a transepithelial voltage (Ve) of 12 mV (retina side positive) and had an electrical resistance (R) of 300 ohm-cm2. These values can be attributed to the RPE. Furosemide and ouabain reduced the Ve without affecting R when applied to the apical side of the RPE, but had no effect upon Ve and R when applied to the choroidal side. Acetazolamide had no effect upon Ve and R when applied to either side of the tissue. In Cl-free medium, ouabain reduced Ve without affecting R, while furosemide had no effect upon Ve and R. In Na-free medium, ouabain and furosemide had no effect upon Ve and R. Unidirectional isotope flux studies performed under open circuit conditions showed a net retina-to-choroid Cl flux that was abolished by furosemide. These results indicate that bovine RPE possesses a furosemide-sensitive Cl transport system.
Frambach
D A
DA
Department of Ophthalmology, University of Southern California, Los Angeles.
Valentine
J L
JL
Weiter
J J
JJ
D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002417:Cattle; D002712:Chlorides / Q000378:metabolism*; D004553:Electric Conductivity; D005665:Furosemide / Q000494:pharmacology*; D010042:Ouabain / Q000494:pharmacology; D010857:Pigment Epithelium of Eye / Q000378:metabolism* / Q000502:physiology
D002712:Chlorides; D010042:Ouabain; D005665:Furosemide