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See also comment(s) by Thomas Yorio •
To clarify the potential role of endothelin-1 (ET-1) in the pathogenesis of glaucoma, the endothelin receptors expressed in bovine trabecular meshwork (TM) and ciliary muscle (CM) were identified. TM and CM strips were subjected to ET-1 as well as to specific endothelin receptor antagonists. In both tissues BQ123, a specific ET-A receptor antagonist, substantially inhibited ET-1-induced contraction. BQ788, a specific ET-B receptor antagonist, showed only moderate effects. Both ET receptor types were detected in bovine TM and CM using Western blot analysis. ET-1 produced an increase in intracellular calcium in cultured TM cells. This effect was inhibited by BQ123, but not by BQ788. Thus, although both receptors are present, the ET-A receptor appears to play the predominant role in mediating contraction in both the TM and CM, while the ET-B receptor seems to contribute little to the overall ET-1 effect.
Dr. L. Choritz, Augenklinik und Hochschulambulanz, Universitätsmedizin Berlin, Berlin, Germany
2.5.1 Trabecular meshwork (Part of: 2 Anatomical structures in glaucoma > 2.5 Meshwork)
3.1 Microscopy (Part of: 3 Laboratory methods)