Scheduled meal accelerates entrainment to a 6‐h phase advance by shifting central and peripheral oscillations in rats

Abstract

Travelling across several time zones requires a fast adjustment of the circadian system and the differential adjustment speeds of organs and systems results in what is commonly referred as jet lag. During this transitory state of circadian disruption, individuals feel discomfort, appetite loss, fatigue, disturbed sleep and deficient performance of multiple tasks. We have demonstrated that after a 6-h phase advance of the light-dark cycle (LD) scheduled food in phase with the new night onset can speed up re-entrainment. In this study, we explored the possible mechanisms underlying the fast re-entrainment due to the feeding schedule. We focused on first- and second-order structures that provide metabolic information to the suprachiasmatic nucleus (SCN). We compared (i) control rats without change in LD cycle; (ii) rats exposed to a 6-h phase advance of the LD cycle with food ad libitum; and (iii) rats exposed to the 6-h phase advance combined with food access in phase with the new night. We found an immediate synchronizing effect of food on stomach distention and on c-Fos expression in the nucleus of the solitary tract, arcuate nucleus of the hypothalamus, dorsomedial hypothalamic nucleus and paraventricular nucleus. These observations indicate that in a model of jet lag, scheduled feeding can favour an immediate shift in first- and second-order relays to the SCN and that by keeping feeding schedules coupled to the new night, a fast re-entrainment may be achieved by shifting peripheral and extra-SCN oscillations.

Time-restricted feeding restores muscle function in Drosophila models of obesity and circadian-rhythm disruption

“…TRF also reduces the risk for compromised muscle function in flies held under continuous light and adds to a growing interest in adjusting mealtime as an effective approach to cope with shiftwork. In a rat model of jetlag or shiftwork, TRF aligns with the nocturnal active phase of the animal that rapidly re-entrains the peripheral circadian clocks 57 . This can reduce desynchronization between clocks in the neural and the peripheral tissues and may improve metabolic health.…”

Phasic Neuronal Firing in the Rodent Nucleus of the Solitary Tract ex vivo

“…Accumulating evidence place the DVC, including the AP and NTS, as an important hindbrain circadian timekeeping centre (Kaneko et al, 2009;Ubaldo-Reyes et al, 2017;Chrobok et al, 2020). Interestingly, in our previous study, we identified an area of the NTS adjacent to the AP in which circadian rhythmicity in the Per2 clock gene expression was sustained in ex vivo brain slices for up to a week in culture.…”

Effect of Daily Light on c-Fos Expression in the Suprachiasmatic Nucleus under Jet Lag Conditions

“…Since a brief light exposure (30 to 60 min of 200 lux light) at subjective night increases c-Fos expression selectively in the ventrolateral part of the SCN [ 8 , 16 ], light may be the causative to affect the SCN cells under jet lag conditions. Compared to c-fos expression in the SCN under jet lag conditions in rats [ 12 , 23 ], we found c-Fos positive cells in wider parts of the SCN, including its central area (See Fig. 1 , Fig.…”