Concentration-dependent morphologic effects of cytochalasin B in the aqueous outflow system.
Cytochalasin B at concentrations of 1, 5, 10, 15, 20, or 40 microgram/ml was continuously exchange-perfused into the eyes of nine living Macaca mulatta monkeys while intraocular pressure (IOP) was maintained at 25 mm Hg for 30 min. Pressures were then slowly reduced to 4 mm Hg to permit blood to reflux into Schlemm's canal as a tracer, and the eyes were fixed while maintained at 4 mm Hg IOP. Tissues were examined in all eyes by light and transmission electron microscopy. At concentrations of 1, 5, and 10 microgram/ml cytochalasin B, the integrity of the endothelial lining of the trabecular wall of Schlemm's canal was maintained. At 15 microgram/ml cytochalasin B, 6% of the length of the endothelial lining was disrupted; at 20 microgram/ml, 54%; and at 40 microgram/ml, 83%. There was a washout of extracellular material at the site of breaks and also a reflux of blood from Schlemm's canal into the trabecular meshwork in the same regions.
D000818:Animals; D001082:Aqueous Humor / Q000187:drug effects*; D003571:Cytochalasin B / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004727:Endothelium / Q000473:pathology / Q000648:ultrastructure; D005123:Eye / Q000187:drug effects* / Q000473:pathology / Q000648:ultrastructure; D000882:Haplorhini; D007429:Intraocular Pressure; D008253:Macaca mulatta; D008854:Microscopy, Electron; D012590:Sclera / Q000187:drug effects; D014129:Trabecular Meshwork / Q000473:pathology
D003571:Cytochalasin B