Having previously reported that topical
dihydroergocristine dose-dependently reduces intraocular pressure in ocular normotensive rabbits with a maximum response and potency higher than those of
timolol and
pilocarpine, the aim of the present work was to assess the effect of this
drug in
alpha-chymotrypsin-induced ocular hypertensive rabbits. Intraocular pressure was measured with a pneumatonometer. The experiments examining the effects of
dihydroergocristine on intraocular pressure were conducted in 10 albino rabbits in which
ocular hypertension was induced by
intracameral injection of
alpha-chymotrypsin. Intraocular pressure responses to
drug vehicle and 5 different doses of topical
dihydroergocristine were studied in order to obtain a dose-response curve. Tonographies were also performed in ocular hypertensive rabbits 2 h after vehicle and
dihydroergocristine instillation to ascertain the actions of this
drug on aqueous humor dynamics. Topical
dihydroergocristine was found to lower intraocular pressure in
alpha-chymotrypsin-induced ocular hypertensive rabbits in a dose-related manner, with the ED50 of the concentration-response curve very similar to that previously obtained in ocular normotensive rabbits. Data from tonographic studies indicate that
dihydroergocristine reduces intraocular pressure in this animal model for
glaucoma by decreasing the aqueous humor inflow. Our findings suggest that topical
dihydroergocristine may be useful in the treatment of
ocular hypertension.