Immediate increase in aqueous humour endothelin 1 concentration and intra-ocular pressure after argon laser trabeculoplasty in the rabbit

Purpose: To investigate the immediate changes of aqueous humour endothelin 1 (ET-1) concentration and intra-ocular pressure (IOP) after argon laser trabeculoplasty (ALT) in the rabbit. Methods: Standard ALT was performed in one eye of 11 pigmented rabbits. IOP was measured with a Tono-Pen-2 tonometer before treatment, under general anaesthesia. Postlaser IOP measurements followed by aqueous humour aspiration were performed under general anaesthesia 30 and 60 min after treatment in 6 and in 5 animals, respectively. Results: The aqueous humour ET-1 concentration was significantly higher (55.0 pg/ml) after ALT than in the contralateral eyes without laser treatment (8.2 pg/ml, p = 0.001). IOP increased significantly after ALT (p = 0.007) but remained unaltered (p = 0.10) in the contralateral eyes without treatment. No statistically significant difference was found either in postlaser IOP elevation or in interocular ET-1 difference between the groups. Conclusions: The results suggest that in the rabbit the increase in aqueous humour ET-1 concentration after ALT is immediate, detectable even 30 min after the laser treatment, followed by no further increase during the second 30-min period after ALT, and associated with an immediate postlaser IOP elevation within 1 h after ALT, These findings may suggest a similar response to ALT in the human eye, since a similar immediate IOP elevation is frequently observed after ALT in the clinical practice. Copyright (C) 2000 S. Karger AG, Basel.