Polyphosphoinositide hydrolysis in response to light stimulation of rat and chick retina and retinal rod outer segments |
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Authors: | F A Millar S C Fisher C A Muir E Edwards J N Hawthorne |
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Affiliation: | Department of Biochemistry, University of Nottingham Medical School, U.K. |
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Abstract: | Phosphoinositides of chick and rat retina were labelled with [3H]inositol. Exposure of retinal preparations to light for 30 s caused loss of labelled phosphatidylinositol 4,5-bisphosphate and to a smaller extent of the other phosphoinositides. Similar light-induced changes were seen when rod outer segment preparations were used and, when these were illuminated in calcium-free media, phosphatidylinositol 4,5-bisphosphate was the only lipid affected. No inositol 1,4,5-trisphosphate was seen after either 30 s or 5 s of illumination of retina or 30 s illumination of rod outer segments. It is concluded that this compound plays no direct part in vertebrate photoreceptor light transduction, though phosphoinositide metabolism might relate to adaptation mechanisms. |
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