Abstract
Purpose::
Despite structural similarity with prostaglandin F2α, the ocular hypotensive agent, bimatoprost (Lumigan), shows unique pharmacological property and functional activity. Unfortunately, the precise mechanisms that underlie bimatoprost’s distinctive impact on aqueous humor dynamics are unclear. The purpose of the current study was to investigate the effects of bimatoprost and a novel prostamide-selective antagonist, AGN 211334, on human conventional drainage pathway.
Methods::
Human anterior segments in organ culture were employed as a model to test the consequences of bimatoprost and/or AGN 211334 treatment on conventional drainage pathway. The anterior segments were perfused at a constant flow rate of 2.5µl/min while pressure was recorded continuously and central corneal thickness was measured every 24 hours. After stable baseline facilities were established, segments were treated with drug(s) and pressure was monitored for an additional two or three days.
Results::
Bimatoprost increased outflow facility by an average of 40 ± 10 % within 48 hours of treatment (n=10, p<0.001). Preincubation or coincubation with AGN 211334 blunted bimatoprost effects by 95% (n=6) or 43% (n=4), respectively. In addition, preincubation with AGN 211334 alone decreased outflow facility by 4% (p=0.04).
Conclusions::
Our findings indicate that bimatoprost interacts with a prostamide receptor in the trabecular meshwork to increase outflow facility.
Keywords: anterior segment • receptors: pharmacology/physiology • intraocular pressure