Zebrafish brain contain multiple dampened oscillators

BORSETTI H.M; HERNANDEZ DE BORSETTI N.E; CAHILL G.M.

Florida, San Destin

Encuentro; 10 th Meeting Society for Research in Biological Rhythms; 2006

Society for Research in Biological Rhythms

Zebrafish brain contain multiple dampened oscillators Borsetti H.M.*, Hernandez de Borsetti N.E. and Cahill G.M. Department of Biology and Biochemistry, Science and Research Building II, University of Houston, Houston, Tx 77204, U.S.A. Zebrafish is a circadian model recently described having multiple peripheral oscillators; indeed the circadian clock was demonstrated even at the cellular level and they can respond not only to light, but also to temperature. Zebrafish pineal gland clock has been previously reported at the melatonin secretion level. However no central pacemaker has been reported in zebrafish. Zebrafish brain can be divided anatomically in: telencephalon, diencephalon, mesencephalon, metencephalon, myelencephalon and medulla spinalis. Neural tissues from these brain areas were dissected from zebrafish carrying the Per3-luciferase transgene and were cultured to monitor the intrinsic Per3 expression patterns in the different brain areas. The rhythmic expression of Per-3-luc was measured during 7 days by topcount scintillation at 24°C in constant darkness condition.  Circadian rhythmicity was observed in vitro in most of the brain areas studied, but in all the cases was also observed a dampening along the time. Some brain areas (such as telencephalon or optic tectum) exhibited at least 3 cycles of oscillations; while other areas (such as the olfactory bulb) expressed rhythmicity that persisted during the whole recording period. However, as previously observed pineal gland exhibited a robust and stable oscillation with no dampening during the recording time. We conclude that zebrafish brain contains multiple dampened circadian oscillators