Throughout the body, mechanical perturbations are transduced into neurochemical signals by the release of
ATP from non-neuronal cells. As an increased intraocular pressure (IOP) can initiate mechanical changes, we hypothesized that extracellular levels of
ATP might be increased in the anterior chamber of human patients with primary acute
angle closure glaucoma (PAACG).
ATP levels in aqueous humor samples were determined using the
luciferin-
luciferase assay. Samples were obtained from 18 controls scheduled for
cataract extraction and from 14 subjects with
angle closure glaucoma during paracentesis. All subjects with
angle closure glaucoma had remarkably elevated levels of
ATP in their aqueous humor. The mean
ATP concentration was ninefold higher for patients with
angle closure glaucoma than for control. The concentration of
ATP was correlated with IOP levels, further supporting a causal relationship.
ATP levels were not influenced by the duration of the PAACG attack, suggesting the rate of
ATP release was sustained. We conclude that increased IOP leads to increased levels of extracellular
ATP in the anterior chamber. This elevated
ATP may contribute to the extreme
pain experienced by subjects with
angle closure glaucoma, and may serve as a source of elevated
adenosine in the anterior chamber.