The Food-Entrainable Oscillator: A Network of Interconnected Brain Structures Entrained by Humoral Signals?

Carneiro, Breno Tercio Santos; Araújo, John Fontenele

doi:10.3109/07420520903404480

Cited by 72 publications

(63 citation statements)

References 90 publications

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“…Circadian rhythms are primarily entrained by light, but other cues, such as timed food signals (or temporally restricted feeding; RF), can also serve as potent entrainment signals that trigger behavioral and physiological rhythms expressed in the circadian range (3). These food-entrained rhythms are accompanied by phase resetting of the molecular clock in the brain (4,5) and various peripheral tissues (6), but not in the light-entrainable pacemaker, the suprachiasmatic nucleus (SCN) (4,5).…”

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confidence: 99%

PKCγ participates in food entrainment by regulating BMAL1

Zhang¹,

Abraham

Lin³

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

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Temporally restricted feeding (RF) can phase reset the circadian clocks in numerous tissues in mammals, contributing to altered timing of behavioral and physiological rhythms. However, little is known regarding the underlying molecular mechanism. Here we demonstrate a role for the gamma isotype of protein kinase C (PKCγ) in food-mediated entrainment of behavior and the molecular clock. We found that daytime RF reduced late-night activity in wild-type mice but not mice homozygous for a null mutation of PKCγ (PKCγ). Molecular analysis revealed that PKCγ exhibited RF-induced changes in activation patterns in the cerebral cortex and that RF failed to substantially phase shift the oscillation of clock gene transcripts in the absence of PKCγ. PKCγ exerts effects on the clock, at least in part, by stabilizing the core clock component brain and muscle aryl hydrocarbon receptor nuclear translocator like 1 (BMAL1) and reducing its ubiquitylation in a deubiquitination-dependent manner. Taken together, these results suggest that PKCγ plays a role in food entrainment by regulating BMAL1 stability.

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confidence: 99%

PKCγ participates in food entrainment by regulating BMAL1

Zhang¹,

Abraham

Lin³

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

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“…The discovery of these food-entrained clocks in the whole body has led to propositions that food anticipatory rhythms are controlled by interactions between peripheral and central food-entrained clocks (Escobar, Cailotto, Angeles-Castellanos, Delgado, & Buijs, 2009). However, despite intense research, the location and organization of the FEO and its entraining pathways and mechanisms have not been described (Davidson, 2009;Carneiro & Araujo, 2009). The finding that sympathetic and parasympathetic afferents are unnecessary for the emergence of FAA in rats has led to the notion that a circulating humoral factor may be involved in the gut-brain communication that is thought to be necessary for the expression of food anticipatory behaviors (Comperatore & Stephan, 1990;.…”

Section: Introductionmentioning

confidence: 99%

Daily anticipatory rhythms of behavior and body temperature in response to glucose availability in rats.

Carneiro

Fernandes

Medeiros

et al. 2012

Psychology & Neuroscience

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When food is available recurrently at a particular time of day, several species increase their locomotion in the hours that precede food delivery, a phenomenon called food anticipatory activity (FAA). In mammals, many studies have shown that FAA is driven by a food-entrained circadian oscillator (FEO) that is distinct from the light-entrained pacemaker in the suprachiasmatic nucleus of the hypothalamus. Few studies have investigated the effect of sugar ingestion on food anticipatory rhythms and the FEO. We aimed to extend the understanding of the role of glucose on the emergence of food anticipatory rhythms by investigating whether glucose ingestion is sufficient to produce daily food anticipation, reflected by motor activity and core body temperature rhythms. Under a 12 h/12 h light/dark cycle, chow-deprived rats had glucose solution available between Zeitgeber Time (ZT) 6 and ZT 9 for 10 days (glucose restriction group), whereas control animals had chow available within the same time window (chow restriction group). Animals in both groups exhibited anticipatory motor activity and body temperature around the fourth day of the scheduled food restriction. Glucose-fed rats ingested ~15 kcal on the days immediately before FAA emergence and reached an intake of ~20 kcal/day, whereas chow-fed rats ingested ~40 kcal/day. The glucose restriction group exhibited a pattern of food anticipation (activity and temperature) that was extremely similar to that observed in the chow restriction group. We conclude that glucose ingestion is a sufficient temporal cue to produce recurrent food anticipation, reflected by activity and temperature rhythms, in rats.

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“…When food is plentiful, feeding behavior is synchronized with the light/dark SCN-driven activity cycle. However, in conditions of scarcity or restricted access to food, feeding rhythms can be driven by the food-entrainable oscillator (FEO), which is independent of SCN light entrainment and is believed to involve multiple regions of the central nervous system (8)(9)(10). It remains unclear how hepatocytes balance the respective roles of systemic circadian regulation applied by the SCN and FEO vs. cell-autonomous regulation from the hepatic clock to generate circadian rhythms in liver functions.…”

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confidence: 99%

Cell-autonomous circadian clock of hepatocytes drives rhythms in transcription and polyamine synthesis

Atwood

DeConde²,

Wang

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

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The circadian clock generates daily rhythms in mammalian liver processes, such as glucose and lipid homeostasis, xenobiotic metabolism, and regeneration. The mechanisms governing these rhythms are not well understood, particularly the distinct contributions of the cell-autonomous clock and central pacemaker to rhythmic liver physiology. Through microarray expression profiling in Met murine hepatocytes (MMH)-D3, we identified over 1,000 transcripts that exhibit circadian oscillations, demonstrating that the cell-autonomous clock can drive many rhythms, and that MMH-D3 is a valid circadian model system. The genes represented by these circadian transcripts displayed both cophasic and antiphasic organization within a protein-protein interaction network, suggesting the existence of competition for binding sites or partners by genes of disparate transcriptional phases. Multiple pathways displayed enrichment in MMH-D3 circadian transcripts, including the polyamine synthesis module of the glutathione metabolic pathway. The polyamine synthesis module, which is highly associated with cell proliferation and whose products are required for initiation of liver regeneration, includes enzymes whose transcripts exhibit circadian oscillations, such as ornithine decarboxylase and spermidine synthase. Metabolic profiling revealed that the enzymatic product of spermidine synthase, spermidine, cycles as well. Thus, the cell-autonomous hepatocyte clock can drive a significant amount of transcriptional rhythms and orchestrate physiologically relevant modules such as polyamine synthesis.networks | chronobiology | resistance distance M any aspects of mammalian physiology and behavior display circadian (∼24-h) rhythms, including the sleep/wake cycle, blood pressure, heart rate, metabolism, and liver regeneration (1, 2). These rhythms are regulated by the circadian clock, which enables consolidation and coordination of physiological events to specific phases of the 24-h cycle in anticipation of daily environmental changes. Dysfunction of the clock is associated with serious human health conditions, including shift work syndrome, sleep disorders, increased risk of cancer, cardiovascular disease, and metabolic syndrome (1, 2).The circadian clock is a self-sustaining, entrainable, cell-autonomous network of three interlocked transcriptional negative feedback loops (2). The primary loop consists of BMAL1/CLOCK transcriptional activators, which dimerize and turn on transcription of Period (Per1, Per2, and Per3) and Crytochrome (Cry1 and Cry2) genes through E-box elements. PER and CRY proteins dimerize and feed back to inhibit BMAL1/CLOCK activation. Two associate loops interlock with the core loop: the ROR/REV-ERB element (RRE) loop composed of ROR activators (RORa, RORb, and RORc) and REV-ERB repressors (REV-ERBα and REV-ERBβ), which compete for RRE transcription factor binding sites (TFBS), and the D-box loop composed of the activator DBP and repressor E4BP4, which act through D-box TFBS (2).In addition to internal regulation of clock genes,...

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The Food-Entrainable Oscillator: A Network of Interconnected Brain Structures Entrained by Humoral Signals?

Cited by 72 publications

References 90 publications

PKCγ participates in food entrainment by regulating BMAL1

PKCγ participates in food entrainment by regulating BMAL1

Daily anticipatory rhythms of behavior and body temperature in response to glucose availability in rats.

Cell-autonomous circadian clock of hepatocytes drives rhythms in transcription and polyamine synthesis

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