Purpose: To report data showing no effect of endothelin-1 on aqueous humor formation and total outflow facility in the cynomolgus monkey, in contrast to the enhancement of outflow facility in monkeys and the suppression of aqueous humor flow in rabbits previously reported by others.
Methods: Living monkeys received, unilaterally: (i) intracameral endothelin-1 (10 microl bolus, or 2ml or 4ml exchange; final intracameral concentration 1 or 10 nM) with total outflow facility measured for up to 1 hr post-treatment by two-level constant pressure perfusion, and (ii) intravitreal endothelin-1 (20 microl, final intravitreal concentration 0.1 or 1 microM) with aqueous humor flow measured by scanning fluorophotometry for 5 hr starting 12 hr post-treatment. Contralateral eyes received vehicle.
Results: Endothelin-1 had no effect on total outflow facility or aqueous humor flow with any of the methods described.
Conclusion: Endothelin-1 seems have a variable effect on aqueous humor dynamics within and between species.