Effect of topical pergolide on aqueous dynamics in normal and glaucomatous monkeys

The effects of pergolide mesylate, an ergoline derivative, were studied on intraocular pressure (IOP), outflow facility, aqueous humor flow, and pupil size in monkeys. Unilateral topical administration of two 20-μl drops of 0·1% pergolide significantly lowered IOP in the treated- and contralateral eye in both normal- and glaucomatous monkeys. In 12 normal monkeys, the baseline IOP of 18·3 ± 0·4 mmHg [mean ± s.e.(m.)] was maximally reduced to 14·4 ± 0·7 mmHg in the treated eye (P < 0·001) and 14·6 ± 0·6 mmHg in the contralateral eye (P < 0·001) at 2 hr after drug administration. In 10 monkeys made bilaterally glaucomatous by argon laser treatment of the trabecular meshwork, the baseline IOP of 33·9 ± 3·0 mmHg [mean ± s.e.(m.)] in the treated eyes and 31·7 ± 3·3 mmHg in the untreated eyes maximally decreased to 23·9 ± 2·2 mmHg (P < 0·05) and 26·2 ± 3·3 mmHg (P < 0·005), respectively, at 5 hr. No significant change (P > 0·7) in outflow facility occurred in either eye of 11 normal monkeys 2 hr after unilateral 0·1% pergolide treatment. In six normal monkeys, the baseline aqueous humor flow of 1·58 ± 0·20 μl min^-1 in treated eyes and 1·44 ± 0·18 μl min^-1 in untreated eyes was reduced to 0·92 ± 0·08 μl min^-1 (P < 0·02) and 1·09 ± 0·11 μl min^-1 (P > 0·10), respectively, from 0·5- to 3·5 hr after drug administration. A mydriatic response was observed in both eyes after unilateral treatment from 1- to 2 hr in eight normal monkeys. By the third day of treatment, bilateral twice a day 0·1% pergolide drops in eight glaucomatous monkey eyes no longer significantly (P > 0·05) decreased IOP.