Immunolocalization of prostanoid EP receptor isotypes in human trabecular meshwork.

Purpose: To assess the localization of the EP-type prostanoid receptors in the human trabecular meshwork (TM) and to determine their spatial distribution in relation to the contractile a-smooth muscle actin fibres.

Methods: Cryosections of human anterior segments were obtained from 17 different donors and immunostained with different EP receptor subtype specific antibodies. Double staining for the EP2 receptor and smooth muscle actin was carried out.

Elevation of nitric oxide production in human trabecular meshwork by increased pressure.

Background: The presence of the nitric oxide (NO)-producing enzyme nitric oxide synthase (NOS) in the trabecular meshwork and the effect of various drugs acting through the NO pathway on the outflow facility and trabecular contractility suggest a role for NO in the regulation of outflow and intraocular pressure (IOP).

Methods: To model the effect of elevated IOP on the NO production in the trabecular meshwork, we perfused anterior segments of human donor eyes in vitro and studied the effect of raised perfusion pressure on NO levels in the perfusate. Furthermore, we evaluated using quantitative PCR whether enhanced perfusion pressure had an effect on the NOS gene expression levels.

Optineurin gene expression level in human trabecular meshwork does not change in response to pressure elevation.

Mutations in the gene optineurin (OPTN) have been associated with primary-open angle glaucoma. Here we present a study on the level of OPTN gene expression in the human trabecular meshwork in response to increased perfusion pressure in the anterior chamber perfusion model of the human eye. Perfusion pressure was raised from 10 to 30 mm Hg for periods ranging between 1 and 24 h.

Nitric oxide/guanylate cyclase pathways and flow in anterior segment perfusion.

Background: The nitric oxide/guanylate cyclase pathway has been suggested to participate in the regulation of intraocular pressure. In the present study, the involvement of nitric oxide pathways on the outflow through the trabecular meshwork was assessed using pharmacological manipulation of the nitric oxide pathway.

Methods: Anterior segments of human donor eyes were maintained in an organ culture perfusion system, and the effects of L-NAME, an inhibitor of nitric oxide synthase, on the flow rate was determined.

Effects of elevated pressure on prostanoid receptor gene expression levels in human trabecular meshwork.

The purpose of this study was to assess the effects of increased intraocular pressure on the expression levels of the prostanoid receptor genes (DP, EP(1-4), FP, IP, TP) in the trabecular meshwork of human donor eyes. Anterior segments of human donor eyes were perfused in an ex vivo anterior segment perfusion system under different pressure regimes. The expression levels of the prostanoid receptors and of several housekeeping genes were assessed by non-competitive real-time quantitative polymerase chain reaction (Q-PCR).