INVESTIGADORES
VALENTINUZZI veronica Sandra
congresos y reuniones científicas
Título:
Shynchronization of daily activity rhythms of a subterranean rodent (Ctenomys sp) by light/dark cycles
Autor/es:
TACHINARDI P; FLÔRES DEFL; TOMOTANI B; ODA GA; VALENTINUZZI VS
Lugar:
Mendoza, Argentina
Reunión:
Congreso; 10th International Mammalogical Congress; 2009
Institución organizadora:
IFM; SAREM, GIB, IADIZA, CCT, CONICET
Resumen:
Tuco-tucos (Ctenomys sp.) from the Argentine Province of La Rioja are solitary animals, active both during the day and night in their natural habitat. However, when exposed to a controlled photoperiod in laboratory, appear to be strictly nocturnal. The activity rhythm persisted under constant darkness in the controlled laboratory environment, showing that they are not a reaction to the external cycles but are rather controlled by an internal clock. In mammals, the circadian clock that controls these rhythms is located in the hypothalamus and is synchronized mainly by the day-night cycle of the Earth. If the underground environment is not exposed to these daily light transitions, how can subterranean animals synchronize their activity rhythms to the above ground environmental cycles? We are evaluating the synchronization mechanisms by analyzing the daily rhythm in sensitivity of the clock to light stimuli. This is measured indirectly by the temporal assay of the running-wheel activity rhythm of rodents exposed to controlled light stimuli. Fourteen animals in individual cages were kept in constant darkness, and received 15 minutes light pulses in different phases of their circadian activity/rest rhythm. Results, assembled as the Phase Response Curve (PRC), show temporal differences between onsets of activity before and after the pulse as a function of the phase when the light pulses were delivered. These data are the first step towards understanding whether, and how, subterranean rodents synchronize their activity to light/dark cycles in their natural habitat.