Polyphosphoinositide hydrolysis in response to light stimulation of rat and chick retina and retinal rod outer segments.
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.
Millar
F A
FA
Department of Biochemistry, University of Nottingham Medical School, U.K.
Fisher
S C
SC
Muir
C A
CA
Edwards
E
E
Hawthorne
J N
JN
D000818:Animals; D002642:Chick Embryo; D006868:Hydrolysis; D007295:Inositol Phosphates / Q000378:metabolism; D008297:Male; D010716:Phosphatidylinositols / Q000302:isolation & purification / Q000378:metabolism*; D010775:Photic Stimulation; D010786:Photoreceptor Cells / Q000032:analysis / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D012160:Retina / Q000032:analysis / Q000378:metabolism* / Q000502:physiology; D012374:Rod Cell Outer Segment / Q000032:analysis / Q000378:metabolism* / Q000502:physiology
D007295:Inositol Phosphates; D010716:Phosphatidylinositols