Endothelial nitric oxide synthase (eNOS) is localized to Muller cells in all vertebrate retinas

The distribution of endothelial nitric oxide synthase immunoreactivity (eNO S-IR) was investigated in the retinas of all phylogenetic vertebrate classe s by using a monoclonal eNOS antibody. Confocal light microscopy showed imm unoreactive labeling in Muller cells of fish, frog, salamander, turtle, chi cken, rat, ground squirrel, and monkey retina. In vascularized retinas (rat , monkey), astrocytes and some blood vessels were also stained. Furthermore , eNOS-IR was localized to axon terminals of turtle and fish horizontal cel ls. These observations are the first to show the presence of eNOS-IR in Mul ler glia and horizontal cell structures of the vertebrate retina. (C) 1999 Elsevier Science Ltd. All rights reserved.