Nitrovasodilator effects on intraocular pressure and outflow facility in monkeys

Exp Eye Res. 1994 Jan;58(1):99-105. doi: 10.1006/exer.1994.1199.


The nitrovasodilators nitroglycerin (NTG) and hydralazine (HZN) were investigated for their effects on intraocular pressure (IOP) and outflow facility in the cynomolgus monkey eye in vivo. Fifty microliters of 0.1% HZN were administered topically in masked, randomized, crossover, placebo controlled trials, and by intracameral perfusion. Both NTG and HZN decreased IOP (mean IOP decrease with NTG 4.40 +/- 2.11 (S.E.M.) (+/- 4.7, S.D.) mmHg, P < 0.01, n = 5, with HZN 3.15 +/- 0.85 (S.E.M.) (+/- 2.3, S.D.) mmHg, P = 0.01, n = 7). Outflow facility increased by 92% (P < 0.05) after intracameral bolus injection of 10(-3) mol l-1 NTG, but not at lower doses. Intracameral HZN caused a significant increase in facility of outflow of 28% (P < 0.05) when perfused at a constant concentration of 10(-5) mol l-1, but not at certain other concentrations. These results demonstrate the capacity for topically applied NTG and HZN to reduce IOP in the living primate eye. They further suggest that, at certain drug doses, but not others, the IOP reduction may be mediated, in part, by an action on the outflow apparatus.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Aqueous Humor / drug effects*
  • Depression, Chemical
  • Dose-Response Relationship, Drug
  • Female
  • Hydralazine / pharmacology*
  • Intraocular Pressure / drug effects*
  • Macaca fascicularis
  • Nitroglycerin / pharmacology*
  • Vasodilator Agents / pharmacology*


  • Vasodilator Agents
  • Hydralazine
  • Nitroglycerin