Endothelin-1 and intraocular inflammation in pigmented rabbit eyes

We assessed the function of Endothelin-1 (ET-1) in the development of anterior chamber inflammation in pigmented rabbit eyes. After the injection of ET-1 solution (10(-13), 10(-11), 10(-9), or 10(-7) M, diluted with 300 microL of artificial aqueous humor) into the anterior chamber, the aqueous protein concentration (APC) increased significantly in a dose-dependent fashion. Peak effects were observed 1-2 hours posttreatment. The APC returned to normal 12 hours after the injection. Pretreatment with antiprostaglandin agents, topical indomethacin, or intravenous diclofenac sodium suppressed the increase in APC. In an endotoxin-induced experimental uveitis model, the ET-1 concentration in the aqueous humor was significantly higher than in normal controls, as was the plasma ET-1 level. These results suggest that ET-1 is an important mediator in ocular inflammatory reactions via arachidonic acid cascade.