EDN2 and Hyperglycemia: In the diabetic Akita retina, Edn2 staining was most pronounced in Müller cell endfeet in the inner retina, Müller cell processes in the OPL and throughout the ONL, as well as the inner and outer segments of the photoreceptors (Fig 2F), a pattern that was maintained even after long-term hyperglycaemia in mature diabetic retinae (Fig 3F).