Endothelin-1 effects on aqueous humor dynamics in monkeys

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 aq ueous humor flow in rabbits previously reported by others. Methods: Living monkeys received, unilaterally: (i) intracameral endothelin -1 (10 mu l bolus, or 2ml or 4ml exchange; final intracameral concentration 1 or 10 nM) with total outflow facility measured for up to 1 hr post-treat ment by two-level constant pressure perfusion, and (ii) intravitreal endoth elin-1 (20 mu l, final intravitreal concentration 0.1 or 1 mu M) with aqueo us 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 hu mor bow with any of the methods described. Conclusion: Endothelin-1 seems have a variable effect on aqueous humor dyna mics within and between species.