Differential Regulation of Arylalkylamine N-Acetyltransferase Activity in Chicken Retinal Ganglion Cells by Light and the Circadian Clock

DIEGO J. VALDEZ; EDUARDO GARBARINO-PICO; NICOLAS M. DIAZ; MARIO E. GUIDO

TAYLOR & FRANCIS INC

Lugar: Londres; Año: 2012 vol. 29 p. 1011 - 1011

p style="TEXT-ALIGN: justify; LINE-HEIGHT: 200%; TEXT-INDENT: 36pt; MARGIN: 0cm 0cm 0pt" class="MsoNormal">Retinal ganglion cells (RGCs) contain circadian clocks driving melatonin synthesis during the day, a subset of these cells acting as non-visual photoreceptors sending photic information to the brain. In this work, we investigated the temporal and light regulation of arylalkylamine N-acetyltransferase (AA-NAT) activity, a key enzyme in melatonin synthesis. We first examined this activity in RGCs of wild-type chickens and compared it to that in photoreceptor cells (PRs) from animals maintained 48 h in constant dark (DD), light (LL), or a regular 12:12 h light/dark (LD) cycle. AA-NAT activity in RGCs displays a circadian rhythmicity with the highest levels during the subjective day in