Ouabain-induced changes in aqueous humour outflow facility and trabecular meshwork cytoskeleton.
BACKGROUND
Inhibition of the Na,K-ATPase by ouabain results in decreased intraocular pressure (IOP), by mechanisms that are not completely understood. Cellular mechanisms that regulate aqueous humour outflow through the trabecular meshwork (TM) include changes in the TM cytoskeleton. Because inhibition of the Na,K-ATPase by ouabain alters the cell's cytoskeleton, the role of the ouabain in regulating aqueous humour outflow and TM cytoskeleton was investigated.


METHODS
Porcine anterior eye segment and low-passage porcine TM cells were used. Outflow facility was measured using perfused anterior eye segment organ culture. Changes in TM cytoskeleton were assessed by rhodamine-phalloidin and anti-paxillin antibody staining and imaged with confocal microscopy.


RESULTS
Ouabain (30 nM to 300 microM) increased outflow facility in perfused eye anterior segments. The time course for ouabain-induced changes in outflow facility correlated with morphological changes in the cytoskeleton of TM cells exposed to ouabain (30 nM to 300 microM). Morphological changes in TM cells include changes in actin filaments and focal adhesions.


CONCLUSIONS
These data suggest that ouabain, at non-toxic concentrations, increases aqueous humour outflow facility possibly by altering the TM cell cytoskeleton.
Dismuke
W M
WM
Department of Pharmacodynamics, University of Florida, 1600 SW Archer Rd, Gainesville, FL 32610, USA.
Mbadugha
C C
CC
Faison
D
D
Ellis
D Z
DZ
D000818:Animals; D001082:Aqueous Humor / Q000187:drug effects* / Q000502:physiology; D002478:Cells, Cultured; D003599:Cytoskeleton / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D007429:Intraocular Pressure / Q000502:physiology; D010042:Ouabain / Q000494:pharmacology*; D013552:Swine; D014129:Trabecular Meshwork / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism
D004791:Enzyme Inhibitors; D010042:Ouabain