CEDIE   05498
CENTRO DE INVESTIGACIONES ENDOCRINOLOGICAS "DR. CESAR BERGADA"
Unidad Ejecutora - UE
artículos
Título:
Involvement of Dopamine Signaling in the Circadian Modulation of Interval Timing
Autor/es:
IVANA L. BUSSI; GLORIA LEVIN; DIEGO GOLOMBEK; PATRICIA V. AGOSTINO
Revista:
EUROPEAN JOURNAL OF NEUROSCIENCE
Editorial:
WILEY-BLACKWELL PUBLISHING, INC
Referencias:
Lugar: Londres; Año: 2014 vol. 40 p. 2299 - 2310
ISSN:
0953-816X
Resumen:
Abstract Duration discrimination within the seconds-to-minutes range, known as interval timing, involves the interaction of the basal ganglia and the prefrontal cortex via dopaminergic-glutamatergic pathways. Besides interval timing, most ? if not all ? organisms exhibit circadian rhythms with periods close to 24 hours. The circadian system modulates performance in several cognitive tasks. We have previously reported that both circadian disruption and desynchronization impaired performance of mice in a 24-second (24s) peak-interval timing task. In this work we studied the involvement of dopamine signaling in the interaction between circadian and interval timing. We report that daily injections of levodopa improved timing performance in the peak-interval (PI) procedure in C57BL/6 mice with circadian disruptions, suggesting that a daily increase of dopamine is necessary for a correct performance in the timing task. Moreover, striatal dopamine levels measured by HLPC-ED indicated a daily rhythm under light/dark (LD) conditions, with lower levels during the day and a peak during the night. This daily variation was affected by inducing circadian disruption under constant light (LL) conditions. We also demonstrated a daily oscillation in tyrosine hydroxylase (TH) levels, dopamine turnover (DOPAC/DA levels), and both mRNA and protein levels of the circadian clock gene Period2 (Per2) in the striatum and substantia nigra, two brain areas relevant for interval timing. In all cases, these oscillations did not persist under LL conditions. We suggest that the lack of dopamine rhythmicity in the striatum under constant light ? probably regulated by Per2 ? could be responsible for impaired performance in the timing task. Our findings add further support to the notion that circadian and interval timing share some common processes, interacting at the level of the dopaminergic system.