H-7 effect on outflow facility after trabecular obstruction following long-term echothiophate treatment in monkeys.

PURPOSE: To determine whether H-7 can enhance outflow facility after trabecular meshwork obstruction by extracellular material that accumulates after long-term treatment of monkeys with the cholinesterase inhibitor echothiophate iodide (ECHO). METHODS: Cynomolgus monkeys were treated topically with 150 microg ECHO in one (n = 4 eyes) or both (n = 8 eyes) eyes for up to 48 weeks. Accommodation response to topical pilocarpine was monitored periodically. Outflow facility response to H-7 was measured by two-level constant pressure perfusion on three or four different occasions after intraocular pressure was elevated for 12 to 18 weeks. RESULTS: Long-term treatment with ECHO decreased the accommodative response to pilocarpine and increased intraocular pressure, as has been reported. Baseline outflow facility was decreased by 46% +/- 7% (n = 12, P < 0.001). H-7 partially restored baseline outflow facility measured during subsequent perfusions while ECHO treatment was continued. Concurrent H-7 enhanced outflow facility by 73% +/- 18% (n = 12, P < 0.005) beyond the same-day baseline in ECHO-treated eyes. Cessation of ECHO treatment further restored baseline outflow facility, and the outflow facility response to H-7. CONCLUSIONS: H-7 can enhance OF in the presence of trabecular obstruction produced by long-term ECHO treatment. This suggests that H-7 may be useful in treating glaucoma, even in the presence of accumulated plaque material that has been described previously.

Prostaglandin subtype-selective and non-selective IOP-lowering comparison in monkeys.

The aim of this study was to determine whether the magnitude of the intraocular-pressure (IOP)-lowering response in monkeys to the nonselective prostaglandin (PG)F(2a)-isopropyl ester (ie) can be reproduced by combining other PG-subtype-selective compounds. IOP was lowered by approximately 25% after 4-5 days of topical administration with latanoprost (FP agonist, 1.5 microg, q.d.), bimatoprost (prostamide, whose metabolites have been shown to be FP agonists; 9 microg, q.d.), or travoprost (FP agonist, 1.2 microg, q.d) or the EP2 agonist, butaprost (25 microg, b.i.d.). The EP1 agonist, 17-phenyl trinor (PhT) PGE2 (b.i.d.), and EP3 agonist, sulprostone (b.i.d.), had no IOP-lowering effects. The addition of butaprost, sulprostone (10 microg), or 17PhTPGE2 (25 microg) to latanoprost did not lower IOP more than latanoprost alone. However, treatment with the combination of latanoprost, 17PhTPGE2, butaprost, and sulprostone produced a similar 50-55% reduction in IOP, as did PGF(2)alpha-ie (b.i.d.). In conclusion, latanoprost, travoprost, and bimatoprost produce similar IOP-lowering responses in normotensive monkeys and are most efficacious when administered q.d. pm, compared to b.i.d. The combination of the FP, EP1, EP2, and EP3 agonists used in this study was sufficient to lower IOP by the same magnitude as PGF(2)alpha-ie, suggesting that combining PG-subtype agonists may be a potent antiglaucoma strategy.