The effect of topical dihydroergocristine on the intraocular pressure in alpha-chymotrypsin-induced ocular hypertensive rabbits.
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.
Melena
J
J
Department of Pharmacology, Faculty of Pharmacy, Basque Country University, Vitoria, Spain.
Santafé
J
J
Segarra
J
J
D000287:Administration, Topical; D000818:Animals; D002918:Chymotrypsin; D004088:Dihydroergotoxine / Q000008:administration & dosage / Q000627:therapeutic use*; D018491:Dopamine Agonists / Q000008:administration & dosage / Q000627:therapeutic use*; D004305:Dose-Response Relationship, Drug; D007429:Intraocular Pressure / Q000187:drug effects*; D009798:Ocular Hypertension / Q000139:chemically induced / Q000188:drug therapy*; D011817:Rabbits; D014065:Tonometry, Ocular
D018491:Dopamine Agonists; D004088:Dihydroergotoxine; D002918:Chymotrypsin