Fluid transport by cultured corneal epithelial cell layers.
OBJECTIVE
Fluid transport across the in vitro corneal epithelium is short lived, hence difficult to detect and characterise. Since stable rates of fluid transport across several cultured epithelial cell layers have been demonstrated, the behaviour of confluent SV40 transformed rabbit corneal epithelial cells (tRCEC) grown on permeable supports was examined.


METHODS
Fluid transport was determined with a nanoinjector volume clamp; the specific electrical resistance of the layers was 184 (SEM 9) Omega cm(2). tRCEC layers transported fluid (from basal to apical) against a pressure head of 3 cm H(2)O for 2-3 hours.


RESULTS
In the first hour, the rate of fluid transport was 5.2 (0.5) microl/h/cm(-2) (n=23), which is comparable with that found in other epithelia. Fluid transport was completely inhibited in 15-30 minutes by either 100 microM ouabain (n=6), 50 microM bumetanide (n=6), or 1 microM endothelin-1 (ET-1; n=6). Preincubation with 10 microM BQ123 (an ET(A) receptor antagonist) obviated inhibition by ET-1 (n=6). ET-1 also caused a 22% decrease in specific resistance.


CONCLUSIONS
Fluid transport appears to depend on transepithelial Cl(- )transport since (1) their directions are the same (stroma-->tear), and (2) both bumetanide and ouabain inhibit it with similar time course. tRCEC appear useful to investigate aspects of the physiology and pharmacology of fluid transport across this layer, including receptor mediated control of this process.
Yang
H
H
Department of Biological Sciences, SUNY College of Optometry, 100 East 24th Street, New York, NY 10010-3677, USA.
Reinach
P S
PS
Koniarek
J P
JP
Wang
Z
Z
Iserovich
P
P
Fischbarg
J
J
D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects / Q000502:physiology; D001826:Body Fluids / Q000378:metabolism*; D002034:Bumetanide / Q000494:pharmacology; D002461:Cell Line, Transformed; D002712:Chlorides; D015194:Diffusion Chambers, Culture; D019573:Epithelium, Corneal / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D010042:Ouabain / Q000494:pharmacology; D011817:Rabbits; D017466:Receptors, Endothelin / Q000378:metabolism; D013449:Sulfonamides / Q000494:pharmacology
D002712:Chlorides; D017466:Receptors, Endothelin; D013449:Sulfonamides; D002034:Bumetanide; D010042:Ouabain