Figure 4.

Flicker-induced vasodilation of retinal blood vessels is depressed in diabetic retinopathy. (A) Flicker-induced vasodilation of primary arterioles and venules is depressed in patients with type 1 diabetes. (Panel A is from Pemp et al. 2009; reprinted, with permission, from the Association for Research in Vision and Ophthalmology © 2009.) B and C show that the depression of flicker-induced vasodilation in diabetic rats is reversed by the iNOS inhibitor aminoguanidine (AG). (B) Both acute AG administration (AG-IV) and chronic administration in drinking water (AG-H₂O) reverses the loss of flicker-induced vasodilation in diabetic animals in vivo. (C) Summary of results. (Panels B and C are from Mishra and Newman 2012; reprinted, with permission, from the authors and Frontiers in Neuroscience Creative Common attribution license.)