ATRIOPEPTIN LOWERS AQUEOUS-HUMOR FORMATION AND INTRAOCULAR-PRESSURE AND ELEVATES CILIARY CYCLIC-GMP BUT LACKS UVEAL VASCULAR EFFECTS IN THEBOVINE PERFUSED EYE
Jc. Millar et al., ATRIOPEPTIN LOWERS AQUEOUS-HUMOR FORMATION AND INTRAOCULAR-PRESSURE AND ELEVATES CILIARY CYCLIC-GMP BUT LACKS UVEAL VASCULAR EFFECTS IN THEBOVINE PERFUSED EYE, Journal of ocular pharmacology and therapeutics, 13(1), 1997, pp. 1-11
The effects of atriopeptin (AP) on intraocular pressure (IOP), aqueous
humor formation (AHF) and ciliary cyclic GMP in bovine eyes perfused
in vitro through a ciliary artery were investigated. AHF was monitored
fluorophotometrically by perfusing the anterior chamber with Barany's
mock aqueous humor containing fluorescein. To study the effect of AP
on cyclic GMP synthesis, eyes were injected with an intra-arterial bol
us of AP prior to dissection of the ciliary processes. For comparison,
individual, ciliary processes, or isolated ciliary epithelial cells w
ere incubated with AP. Cyclic GMP was extracted by homogenization, aqu
eous partition and column chromatography, and measured by radioimmunoa
ssay (RIA). Decreases in IOP or AHF were seen (similar to) 15 min afte
r the injection of AP and persisted throughout a 60-80 min perfusion.
Arterial perfusion pressure was not significantly altered by AP, even
when vascular tone was raised by adding noradrenaline to the perfusate
. In whole eyes, ciliary cyclic GMP increased in response to AP. Cycli
c GMP in isolated ciliary processes, or cultured ciliary epithelial ce
lls incubated with AP also increased. We conclude that the decrease in
IOP in the bovine eye by AP is due to a reduction in AHF, which is in
dependent of any vascular effect. Ciliary cycle GMP may be the intrace
llular mediator involved.