Artículos
Título:
Retina ganglion cells are autonomous circadian oscillators synthesizing N-acetylserotonin during the day.
Autor/es:
E GARBARINO PICO, AR CARPENTIERI, MI KELLER SARMIENTO, MA BROCCO, P PANZETTA, RE ROSENSTEIN, BL CAPUTTO, ME GUIDO.
Editorial:
AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC
Referencias:
Lugar: Bethesda, Maryland; Año: 2004 vol. 279 p. 51172 - 51172
Resumen:
etinal ganglion cells send visual and circadian information
to the brain regarding the environmental lightdark
cycles. We investigated the capability of retinal
ganglion cells of synthesizing melatonin, a highly reliable
circadian marker that regulates retinal physiology,
as well as the capacity of these cells to function as autonomous
circadian oscillators. Chick retinal ganglion
cells presented higher levels of melatonin assessed by
radioimmunoassay during both the subjective day in
constant darkness and the light phase of a light-dark
cycle. Similar changes were observed in mRNA levels
and activity of arylalkylamine N-acetyltransferase, a
key enzyme in melatonin biosynthesis, with the highest
levels of both parameters during the subjective day.
These daily variations were preceded by the elevation of
cyclic-AMP content, the second messenger involved in
the regulation of melatonin biosynthesis. Moreover, cultures
of immunopurified retinal ganglion cells at embryonic