Food as circadian time cue for appetitive behavior

Abstract

Feeding schedules entrain circadian clocks in multiple brain regions and most peripheral organs and tissues, thereby synchronizing daily rhythms of foraging behavior and physiology with times of day when food is most likely to be found. Entrainment of peripheral clocks to mealtime is accomplished by multiple feeding-related signals, including absorbed nutrients and metabolic hormones, acting in parallel or in series in a tissue-specific fashion. Less is known about the signals that synchronize circadian clocks in the brain with feeding time, some of which are presumed to generate the circadian rhythms of food-anticipatory activity that emerge when food is restricted to a fixed daily mealtime. In this commentary, I consider the possibility that food-anticipatory activity rhythms are driven or entrained by circulating ghrelin, ketone bodies or insulin. While evidence supports the potential of these signals to participate in the induction or amount of food-anticipatory behavior, it falls short of establishing either a necessary or sufficient role or accounting for circadian properties of anticipatory rhythms. The availability of multiple, circulating signals by which circadian oscillators in many brain regions might entrain to mealtime has supported a view that food-anticipatory rhythms of behavior are mediated by a broadly distributed system of clocks. The evidence, however, does not rule out the possibility that multiple peripheral and central food-entrained oscillators and feeding-related signals converge on circadian oscillators in a defined location which ultimately set the phase and gate the expression of anticipatory activity rhythms. A candidate location is the dorsal striatum, a core component of the neural system which mediates reward, motivation and action and which contains circadian oscillators entrainable by food and dopaminergic drugs. Systemic metabolic signals, such as ghrelin, ketones and insulin, may participate in circadian food anticipation to the extent that they modulate dopamine afferents to circadian clocks in this area.

Chrono‐nutrition: From molecular and neuronal mechanisms to human epidemiology and timed feeding patterns

“…Circulating metabolic hormones and nutrients, and sensory input from the gastrointestinal tract which following feeding patterns, both engage acute homeostatic responses in a rhythmic fashion (because of normal feeding/fasting cycle), as well as influence central circadian clocks directly, through responsiveness of the molecular clockwork to metabolic state (discussed in more detail below). This sensitivity of the clockwork to food‐related input is exemplified by the strong behavioural and physiological entrainment observed in laboratory animals to restricted feeding schedules (Mistlberger, 2011).…”

Type 1 dopamine receptor (D1R)-independent circadian food anticipatory activity in mice

“…Daily access to food leads to anticipatory behavioral activity that may also be dependent on dopamine signaling [ 30 , 37 , 38 ]. Previous studies of mice with a constitutive knockout (KO) of D1R showed attenuated FAA, whereas D2R KO mice showed normal FAA [ 21 , 39 ].…”

DAILY—A Personalized Circadian Zeitgeber Therapy as an Adjunctive Treatment for Alcohol Use Disorder Patients: Study Protocol for a Randomized Controlled Trial

“…In recent years, there has been growing evidence that circadian rhythms modulate reward circuits and behavior ( 28 – 31 ). For instance, the activation of reward processing is subject to circadian control ( 32 ), the release of neurotransmitters, such as dopamine and serotonin, varies over the course of the day, and dopamine signaling in the SCN has strong impact on its rhythms and processing responses to hedonic stimuli ( 33 , 34 ).…”