Effects of travoprost on aqueous humor dynamics in monkeys.
OBJECTIVE
To determine the mechanism by which travoprost, a prodrug of a prostaglandin F2alpha analog, reduces intraocular pressure (IOP) in cynomolgus monkey eyes.


METHODS
One eye each of 12 monkeys was treated with laser burns to the trabecular meshwork to elevate IOP. At least 4 months later (Baseline Day), IOP was measured by pneumatonometry (9:00 AM and 11:45 AM), and aqueous flow and outflow facility were determined by a fluorophotometric method. Uveoscleral outflow was calculated. Both eyes were treated with travoprost 0.004% at 9:00 AM and 5:00 PM for two days and at 9:30 AM on the third day (Treatment Day), when measurements were repeated as on Baseline Day. Statistical analyses were performed using two-tailed, paired t tests.


RESULTS
On Treatment Day compared with Baseline Day, IOP in hypertensive eyes was reduced at 2.25 hours (25.8 +/- 11.2 vs 33.7 +/- 13.2 mm Hg; mean +/- standard error of the mean [SEM]; P = 0.02) and 16 hours (26.3 +/- 10.2 vs 35.1 +/- 13.6 mm Hg; P = 0.02) after treatment. The increase in uveoscleral outflow was not significant. In normotensive eyes, IOP was reduced at 2.25 hours (19.0 +/- 3.7 vs 23.0 +/- 4.0 mm Hg; P = 0.03) and 16 hours (20.7 +/- 5.4 vs 23.4 +/- 5.3 mm Hg; P = 0.01) after treatment, and uveoscleral outflow was significantly (P = 0.02) increased (1.02 +/- 0.43 vs 0.35 +/- 0.72 microL/min).


CONCLUSIONS
Travoprost reduces IOP in normotensive monkey eyes by increasing uveoscleral outflow. The IOP reduction in hypertensive eyes is probably via the same mechanism, although the increased uveoscleral drainage did not reach statistical significance. Travoprost had no effect on aqueous flow or outflow facility.
Toris
Carol B
CB
Department of Ophthalmology, University of Nebraska Medical Center, Omaha, Nebraska 68198-5840, USA. ctoris@unmc.edu
Zhan
Gui-Lin
GL
Camras
Carl B
CB
McLaughlin
Marsha A
MA
D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology*; D001082:Aqueous Humor / Q000187:drug effects* / Q000378:metabolism*; D003008:Cloprostenol / Q000031:analogs & derivatives* / Q000494:pharmacology*; D004195:Disease Models, Animal; D005260:Female; D015590:Fluorophotometry; D007429:Intraocular Pressure / Q000187:drug effects*; D017075:Laser Coagulation; D008252:Macaca fascicularis; D009798:Ocular Hypertension / Q000188:drug therapy / Q000209:etiology / Q000378:metabolism; D011355:Prodrugs / Q000494:pharmacology*; D014065:Tonometry, Ocular; D014129:Trabecular Meshwork / Q000601:surgery; D000069557:Travoprost
D000959:Antihypertensive Agents; D011355:Prodrugs; D003008:Cloprostenol; D000069557:Travoprost