IOP elevation produced a marked increase in ET_B receptor expression in rat retinas.

<p>Representative IOP elevation profile for 2 weeks (<b>A</b>) and 4 weeks (<b>C</b>) in adult Brown Norway rats. IOP was elevated in one eye (closed circles), while the other eye served as a contralateral control eye (open circles). The experiment was carried out in six Brown Norway rats for 2 weeks and seven Brown Norway rats for 4 weeks of IOP elevation. IOP values were plotted as mean ± SEM. Retinal sections from 2 weeks (<b>B</b>) and 4 weeks (<b>D</b>) IOP elevated rat eyes were immunostained for ET_B receptor expression (green fluorescence) using a custom made rabbit polyclonal ET_B receptor specific antibody. White arrows indicate RGCs in which an increase in immunostaining for ET_B receptors was observed. Retinal sections in which the primary antibody incubation was omitted are labeled as blank and showed minimal fluorescence. NFL, nerve fiber layer; GCL, ganglion cell layer; IPL, inner plexiform layer; OPL, outer plexiform layer; INL, Inner Nuclear Layer; OPL, Outer Plexiform Layer; OS, Rod Outer Segment. Scale bar indicates 20 µm.