Melatonin modulates interval timing in rats: effect of pinealectomy

BUSSI I.L.; LEVÍN, G; GOLOMBEK, D.A.; AGOSTINO, P.V.

Mar del Plata

Congreso; XXX Congreso Anual de la Sociedad Argentina de Investigación en Neurociencia; 2015

Sociedad Argentina de Neurociencias

Interval timing is a complex cognitive process that involves the estimation of time within the seconds-to-minutes range. On the other hand, the circadian system controls physiological and behavioral functions with periods close to 24 h. We have previously reported that short-time perception in mice is influenced by the circadian pacemaker, with dopamine signaling as a link between both temporal systems. In this work we evaluated the involvement of melatonin in the circadian modulation of interval timing, as well as the interaction between this hormone and dopamine function. We report that melatonin-depleted rats showed an impairment in their ability to time short intervals compared to controls. Moreover, melatonin administration restored time estimation accuracy in pinealectomized rats. We also demonstrate that circadian desynchronization caused a transient impairment in this cognitive task. Furthermore, melatonin depletion increased striatal dopamine availability, which was reverted by external melatonin administration. Taken together, our findings add further support to the notion that the circadian system regulates interval timing, probably by using melatonin as an output to regulate dopaminergic functions in structures that are important for interval timing mechanisms.