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Phosphoinositide Metabolism in the Retina: Localization to Horizontal Cells and Regulation by Light and Divalent Cations

1983; Wiley; Volume: 41; Issue: 3 Linguagem: Inglês

10.1111/j.1471-4159.1983.tb04806.x

1471-4159

Robert E. Anderson, Maureen B. Maude, Paula A. Kelleher, Mary E. Rayborn, Joe G. Hollyfield,

Biomedical Research and Pathophysiology

Abstract: Isolated retinas from Xenopus laevis incorporated greater amounts of [ 3 H]inositol and 32 P i into phosphoinositides when incubated in light than did control retinas incubated in the dark. Inositol was primarily incorporated into phosphatidylinositol (83–86%), while phosphate labeled the polyphosphoinositides (72–79%). The incorporation of radioactive glycerol, serine, choline, or ethanolarnine into retinal lipids was unaffected by light. Following incubation with [ 3 H]inositol, the cell type involved in the light response was identified by light and electron microscope autoradiography to be the horizontal cell. These results are consistent with a classic phosphatidylinositol effect in the retina. An interesting feature of this response is that the stimulus (light) is received in the photoreceptor cell and the effect is manifest in the horizontal cell.