The synthesis of Retinal Ganglion Cell Phospholipids is under control of an Endogenous Circadian Clock. Daily Variations in Phospholipid Synthesizing Enzyme Activities

E. GARBARINO-PICO,; A.R. CARPENTIERI,; P. CASTAGNET,; S. PASQUARÉ,; M. GIUSTO, N.; B.L. CAPUTTO,; MARIO EDUARDO GUIDO

WILEY-LISS, DIV JOHN WILEY & SONS INC

Año: 2004 vol. 76 p. 642 - 642

p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; LINE-HEIGHT: 200%; TEXT-ALIGN: justify">Retinal ganglion cells (RGCs) are major components of the vertebrate circadian system. They send information to the brain synchronizing the entire organism to the light-dark cycles. We recently reported that chicken RGCs display daily variations in the biosynthesis of glycerophospholipids in constant darkness (DD). It was unclear if this rhythmicity was driven by this population itself or by other retinal cells. Here we show that RGCs present circadian oscillations in the labeling of 32P-phospholipids both in vivo in constant light (LL) and in cultures of immunopurified embryonic cells. In vivo, there was greater 32P-orthophosphate incorporation into total phospholipids during the subjective day. Phosphatidylinositol (PI) was the utmost 32P-labeled lipid at all time