EXPERIMENTAL GLAUCOMA SIGNIFICANTLY DECREASES ATRIAL-NATRIURETIC-FACTOR (ANF) RECEPTORS IN THE CILIARY PROCESSES OF THE RABBIT EYE

ANF binding sites were analysed in the ciliary processes of rabbits with unilateral experimental glaucoma which had been induced by injecting α-chymotrypsin into the posterior chamber of the right eyes. The intraocular pressure (IOP) of glaucomatous eyes was significantly greater (28·4 ± 4 mmHg) than that of normotensive control eyes (13·1 ± 1·4 mmHg, mean ± s.e.m., n = 23, P < 0·05). ANF concentrations in aqueous humour and the ciliary processes were significantly higher in glaucomatous eyes (91 ± 2 pg ml-1 and 30·4 ± 4·2 pg g-1 wet weight) than in normal eyes (3·1 ± 2·2 pg ml-1 and 10·2 ± 2·7 pg g-1 wet weight, respectively, n = 6, P < 0·01). The number of ANF-binding sites (Bmax) in the ciliary processes of glaucomatous rabbit eyes was significantly decreased in comparison to the controls (24 ± 4 vs. 13 ± 3 fmol mg-1 protein, n = 10, P < 0·05). These data suggest that ANF receptors in the ciliary processes are down-regulated and that ANF may play an important role in the pathophysiology of experimental glaucoma. © 1991.