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Iosif CI, Bashir ZI, Apps R, Pickford J. Cerebellar Prediction and Feeding Behaviour. CEREBELLUM (LONDON, ENGLAND) 2023; 22:1002-1019. [PMID: 36121552 PMCID: PMC10485105 DOI: 10.1007/s12311-022-01476-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 09/01/2022] [Indexed: 06/15/2023]
Abstract
Given the importance of the cerebellum in controlling movements, it might be expected that its main role in eating would be the control of motor elements such as chewing and swallowing. Whilst such functions are clearly important, there is more to eating than these actions, and more to the cerebellum than motor control. This review will present evidence that the cerebellum contributes to homeostatic, motor, rewarding and affective aspects of food consumption.Prediction and feedback underlie many elements of eating, as food consumption is influenced by expectation. For example, circadian clocks cause hunger in anticipation of a meal, and food consumption causes feedback signals which induce satiety. Similarly, the sight and smell of food generate an expectation of what that food will taste like, and its actual taste will generate an internal reward value which will be compared to that expectation. Cerebellar learning is widely thought to involve feed-forward predictions to compare expected outcomes to sensory feedback. We therefore propose that the overarching role of the cerebellum in eating is to respond to prediction errors arising across the homeostatic, motor, cognitive, and affective domains.
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Affiliation(s)
- Cristiana I Iosif
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, University Walk, Bristol, BS8 1TD, UK.
| | - Zafar I Bashir
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, University Walk, Bristol, BS8 1TD, UK
| | - Richard Apps
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, University Walk, Bristol, BS8 1TD, UK
| | - Jasmine Pickford
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, University Walk, Bristol, BS8 1TD, UK
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2
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Tang Q, Assali DR, Güler AD, Steele AD. Dopamine systems and biological rhythms: Let's get a move on. Front Integr Neurosci 2022; 16:957193. [PMID: 35965599 PMCID: PMC9364481 DOI: 10.3389/fnint.2022.957193] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 07/06/2022] [Indexed: 02/05/2023] Open
Abstract
How dopamine signaling regulates biological rhythms is an area of emerging interest. Here we review experiments focused on delineating dopamine signaling in the suprachiasmatic nucleus, nucleus accumbens, and dorsal striatum to mediate a range of biological rhythms including photoentrainment, activity cycles, rest phase eating of palatable food, diet-induced obesity, and food anticipatory activity. Enthusiasm for causal roles for dopamine in the regulation of circadian rhythms, particularly those associated with food and other rewarding events, is warranted. However, determining that there is rhythmic gene expression in dopamine neurons and target structures does not mean that they are bona fide circadian pacemakers. Given that dopamine has such a profound role in promoting voluntary movements, interpretation of circadian phenotypes associated with locomotor activity must be differentiated at the molecular and behavioral levels. Here we review our current understanding of dopamine signaling in relation to biological rhythms and suggest future experiments that are aimed at teasing apart the roles of dopamine subpopulations and dopamine receptor expressing neurons in causally mediating biological rhythms, particularly in relation to feeding, reward, and activity.
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Affiliation(s)
- Qijun Tang
- Department of Biology, University of Virginia, Charlottesville, VA, United States
| | - Dina R. Assali
- Department of Biological Sciences, California State Polytechnic University Pomona, Pomona, CA, United States
| | - Ali D. Güler
- Department of Biology, University of Virginia, Charlottesville, VA, United States
- Program in Fundamental Neuroscience, University of Virginia, Charlottesville, VA, United States
- Department of Neuroscience, School of Medicine, University of Virginia, Charlottesville, VA, United States
| | - Andrew D. Steele
- Department of Biological Sciences, California State Polytechnic University Pomona, Pomona, CA, United States
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Namgyal D, Chandan K, Ali S, Ahmad A, Hashim MJ, Sarwat M. Aberrant Lighting Causes Anxiety-like Behavior in Mice but Curcumin Ameliorates the Symptoms. Animals (Basel) 2021; 11:ani11092590. [PMID: 34573555 PMCID: PMC8466876 DOI: 10.3390/ani11092590] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 08/20/2021] [Accepted: 08/30/2021] [Indexed: 01/11/2023] Open
Abstract
Simple Summary In the present study, we exposed mice to aberrant lighting system and noticed anxiety-like behavior. These symptoms were ameliorated by oral administration of curcumin. The study was carried out on the animals for three weeks in dim light at night (dLAN) and complete darkness (DD), monitoring the body weight, daily food intake, anxiety-like behavior, and expression of the period (PER1) gene. The exposure to dim light at night was found to significantly enhance the anxiety-like behavior and increased the body weight possibly through altered metabolism in mice. In contrast, exposure to DD caused increased anxiety but no significant difference in the body weight. Moreover, the expression of the PER1 gene involved in sleep was also found to be decreased in the aberrant light conditions (dLAN and DD). Although the treatment of curcumin had no effect on the body weight, it had ameliorated the anxiety-like behavior possibly by modulating the expression of the PER1 gene. Thus, the alteration in the light/dark cycle has negative influences on body weight, affecting even the emotional quotient. This study identifies the risk factors associated with aberrant lighting conditions in laboratory animal and ameliorative effects of curcumin. Abstract In the modern research field, laboratory animals are constantly kept under artificial lighting conditions. However, recent studies have shown the effect of artificial light on animal behavior and metabolism. In the present study on mice, following three weeks of housing in dim light at night (dLAN; 5lux) and complete darkness (DD; 0lux), we monitored the effect on body weight, daily food intake, anxiety-like behavior by employing the open field test, and expression of the period (PER1) gene. We also studied the effect of oral administration of different concentrations of curcumin (50, 100, and 150 mg/kg) for three weeks in the same mice and monitored these parameters. The exposure to dLAN had significantly increased the anxiety-like behavior and body weight possibly through the altered metabolism in mice, whereas exposure to DD caused increased anxiety but no significant difference in weight gain. Moreover, the expression of the PER1 gene involved in sleep was also found to be decreased in the aberrant light conditions (dLAN and DD). Although the treatment of curcumin had no effect on body weight, it ameliorated the anxiety-like behavior possibly by modulating the expression of the PER1 gene. Thus, alteration in the light/dark cycle had a negative effect on laboratory animals on the body weight and emotions of animals. The present study identifies the risk factors associated with artificial lighting systems on the behavior of laboratory animals and the ameliorative effects of curcumin, with a focus on anxiety-like behavior.
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Affiliation(s)
- Dhondup Namgyal
- Amity Institute of Neuropsychology and Neuroscience, Amity University, Noida 201303, India;
- Amity Institute of Pharmacy, Amity University, Noida 201303, India;
| | - Kumari Chandan
- Amity Institute of Pharmacy, Amity University, Noida 201303, India;
| | - Sher Ali
- School of Basic Sciences and Research, Department of Life Sciences, Sharda University, Greater Noida 201310, India;
| | - Ajaz Ahmad
- Department of Clinical Pharmacy, College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia;
| | - Maha J. Hashim
- Department of Life Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, UK;
| | - Maryam Sarwat
- Amity Institute of Pharmacy, Amity University, Noida 201303, India;
- Correspondence:
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Assali DR, Sidikpramana M, Villa AP, Falkenstein J, Steele AD. Type 1 dopamine receptor (D1R)-independent circadian food anticipatory activity in mice. PLoS One 2021; 16:e0242897. [PMID: 33556069 PMCID: PMC7869994 DOI: 10.1371/journal.pone.0242897] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 01/27/2021] [Indexed: 01/11/2023] Open
Abstract
Circadian rhythms are entrained by light and influenced by non-photic stimuli, such as feeding. The activity preceding scheduled mealtimes, food anticipatory activity (FAA), is elicited in rodents fed a limited amount at scheduled times. FAA is thought to be the output of an unidentified food entrained oscillator. Previous studies, using gene deletion and receptor pharmacology, implicated dopamine type receptor 1 (D1R) signaling in the dorsal striatum as necessary for FAA in mice. To further understand the role of D1R in promoting FAA, we utilized the Cre-lox system to create cell type-specific deletions of D1R, conditionally deleting D1R in GABA neurons using Vgat-ires-Cre line. This conditional deletion mutant had attenuated FAA, but the amount was higher than expected based on prior results using a constitutive knockout of D1R, D1R KODrago. This result prompted us to re-test the original D1R KODrago line, which expressed less FAA than controls, but only moderately so. To determine if genetic drift had diminished the effect of D1R deletion on FAA, we re-established the D1R KODrago knockout line from cryopreserved samples. The reestablished D1R KODrago-cryo had a clear impairment of FAA compared to controls, but still developed increased activity preceding mealtime across the 4 weeks of timed feeding. Finally, we tested a different deletion allele of D1R created by the Knockout Mouse Project. This line of D1R KOKOMP mice had a significant impairment in the acquisition of FAA, but eventually reached similar levels of premeal activity compared to controls after 4 weeks of timed feeding. Taken together, our results suggest that D1R signaling promotes FAA, but other dopamine receptors likely contribute to FAA given that mice lacking the D1 receptor still retain some FAA.
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Affiliation(s)
- Dina R. Assali
- Department of Biological Sciences, California State Polytechnic University Pomona, Pomona, CA, United States of America
| | - Michael Sidikpramana
- Department of Biological Sciences, California State Polytechnic University Pomona, Pomona, CA, United States of America
| | - Andrew P. Villa
- Department of Biological Sciences, California State Polytechnic University Pomona, Pomona, CA, United States of America
| | - Jeffrey Falkenstein
- Department of Biological Sciences, California State Polytechnic University Pomona, Pomona, CA, United States of America
| | - Andrew D. Steele
- Department of Biological Sciences, California State Polytechnic University Pomona, Pomona, CA, United States of America
- * E-mail:
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5
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Xie X, Kukino A, Calcagno HE, Berman AM, Garner JP, Butler MP. Natural food intake patterns have little synchronizing effect on peripheral circadian clocks. BMC Biol 2020; 18:160. [PMID: 33158435 PMCID: PMC7646075 DOI: 10.1186/s12915-020-00872-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Accepted: 09/17/2020] [Indexed: 01/07/2023] Open
Abstract
Background Circadian rhythms across mammalian tissues are coordinated by a master clock in the suprachiasmatic nucleus (SCN) that is principally entrained by light-dark cycles. Prior investigations have shown, however, that time-restricted feeding (TRF)—daily alternation of fasting and food availability—synchronizes peripheral clocks independent of the light-dark cycle and of the SCN. This has led to the idea that downstream peripheral clocks are entrained indirectly by food intake rhythms. However, TRF is not a normal eating pattern, and it imposes non-physiologic long fasts that rodents do not typically experience. Therefore, we tested whether normal feeding patterns can phase-shift or entrain peripheral tissues by measuring circadian rhythms of the liver, kidney, and submandibular gland in mPer2Luc mice under different food schedules. Results We employed home cage feeders to first measure ad libitum food intake and then to dispense 20-mg pellets on a schedule mimicking that pattern. In both conditions, PER2::LUC bioluminescence peaked during the night as expected. Surprisingly, shifting the scheduled feeding by 12 h advanced peripheral clocks by only 0–3 h, much less than predicted from TRF protocols. To isolate the effects of feeding from the light-dark cycle, clock phase was then measured in mice acclimated to scheduled feeding over the course of 3 months in constant darkness. In these conditions, peripheral clock phases were better predicted by the rest-activity cycle than by the food schedule, contrary to expectation based on TRF studies. At the end of both experiments, mice were exposed to a modified TRF with food provided in eight equally sized meals over 12 h. In the light-dark cycle, this advanced the phase of the liver and kidney, though less so than in TRF with ad libitum access; in darkness, this entrained the liver and kidney but had little effect on the submandibular gland or the rest-activity cycle. Conclusions These data suggest that natural feeding patterns can only weakly affect circadian clocks. Instead, in normally feeding mice, the central pacemaker in the brain may set the phase of peripheral organs via pathways that are independent of feeding behavior.
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Affiliation(s)
- Xiaobin Xie
- Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, 3181 SW Sam Jackson Park Road - L606, Portland, OR, 97239, USA.,Current Address: Key Laboratory of Protein Modification and Degradation, School of Basic Medical Sciences, Guangzhou Medical University, Guangzhou, 511436, China
| | - Ayaka Kukino
- Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, 3181 SW Sam Jackson Park Road - L606, Portland, OR, 97239, USA
| | - Haley E Calcagno
- Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, 3181 SW Sam Jackson Park Road - L606, Portland, OR, 97239, USA
| | - Alec M Berman
- Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, 3181 SW Sam Jackson Park Road - L606, Portland, OR, 97239, USA
| | - Joseph P Garner
- Department of Comparative Medicine, Stanford University, Stanford, CA, USA
| | - Matthew P Butler
- Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, 3181 SW Sam Jackson Park Road - L606, Portland, OR, 97239, USA. .,Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR, USA.
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6
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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.
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Affiliation(s)
- Ralph E Mistlberger
- Department of Psychology, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A2S6, Canada
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7
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Horn M, Mitesser O, Hovestadt T, Yoshii T, Rieger D, Helfrich-Förster C. The Circadian Clock Improves Fitness in the Fruit Fly, Drosophila melanogaster. Front Physiol 2019; 10:1374. [PMID: 31736790 PMCID: PMC6838225 DOI: 10.3389/fphys.2019.01374] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Accepted: 10/17/2019] [Indexed: 12/17/2022] Open
Abstract
It is assumed that a properly timed circadian clock enhances fitness, but only few studies have truly demonstrated this in animals. We raised each of the three classical Drosophila period mutants for >50 generations in the laboratory in competition with wildtype flies. The populations were either kept under a conventional 24-h day or under cycles that matched the mutant’s natural cycle, i.e., a 19-h day in the case of pers mutants and a 29-h day for perl mutants. The arrhythmic per0 mutants were grown together with wildtype flies under constant light that renders wildtype flies similar arrhythmic as the mutants. In addition, the mutants had to compete with wildtype flies for two summers in two consecutive years under outdoor conditions. We found that wildtype flies quickly outcompeted the mutant flies under the 24-h laboratory day and under outdoor conditions, but perl mutants persisted and even outnumbered the wildtype flies under the 29-h day in the laboratory. In contrast, pers and per0 mutants did not win against wildtype flies under the 19-h day and constant light, respectively. Our results demonstrate that wildtype flies have a clear fitness advantage in terms of fertility and offspring survival over the period mutants and – as revealed for perl mutants – this advantage appears maximal when the endogenous period resonates with the period of the environment. However, the experiments indicate that perl and pers persist at low frequencies in the population even under the 24-h day. This may be a consequence of a certain mating preference of wildtype and heterozygous females for mutant males and time differences in activity patterns between wildtype and mutants.
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Affiliation(s)
- Melanie Horn
- Neurobiology and Genetics, Theodor-Boveri Institute, Biocenter, Julius-Maximilians University Würzburg, Würzburg, Germany
| | - Oliver Mitesser
- Theoretical Evolutionary Ecology Group, Biocenter, Department of Animal Ecology and Tropical Biology, Julius-Maximilians University Würzburg, Würzburg, Germany
| | - Thomas Hovestadt
- Theoretical Evolutionary Ecology Group, Biocenter, Department of Animal Ecology and Tropical Biology, Julius-Maximilians University Würzburg, Würzburg, Germany
| | - Taishi Yoshii
- Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan
| | - Dirk Rieger
- Neurobiology and Genetics, Theodor-Boveri Institute, Biocenter, Julius-Maximilians University Würzburg, Würzburg, Germany
| | - Charlotte Helfrich-Förster
- Neurobiology and Genetics, Theodor-Boveri Institute, Biocenter, Julius-Maximilians University Würzburg, Würzburg, Germany
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8
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Abstract
The interplay between the circadian system and metabolism may give animals an evolutionary advantage by allowing them to anticipate food availability at specific times of the day. Physiological adaptation to feeding time allows investigation of animal parameters and comparison of food anticipation between groups of animals with genetic alterations and/or post pharmacological intervention. Such an approach is vital for understanding gene function and mechanisms underlying the temporal patterns of both food anticipation and feeding. Exploring these mechanisms will allow better understanding of metabolic disorders and might reveal potential new targets for pharmacological intervention. Changes that can be easily monitored and that represent food anticipation on the level of the whole organism are a temporarily restricted increase of activity and internal body temperature.
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9
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Pendergast JS, Yamazaki S. The Mysterious Food-Entrainable Oscillator: Insights from Mutant and Engineered Mouse Models. J Biol Rhythms 2018; 33:458-474. [PMID: 30033846 DOI: 10.1177/0748730418789043] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The food-entrainable oscillator (FEO) is a mysterious circadian clock because its anatomical location(s) and molecular timekeeping mechanism are unknown. Food anticipatory activity (FAA), which is defined as the output of the FEO, emerges during temporally restricted feeding. FAA disappears immediately during ad libitum feeding and reappears during subsequent fasting. A free-running FAA rhythm has been observed only in rare circumstances when food was provided with a period outside the range of entrainment. Therefore, it is difficult to study the circadian properties of the FEO. Numerous studies have attempted to identify the critical molecular components of the FEO using mutant and genetically engineered mouse models. Herein we critically review the experimental protocols and findings of these studies in mouse models. Several themes emerge from these studies. First, there is little consistency in restricted feeding protocols between studies. Moreover, the protocols were sometimes not optimal, resulting in erroneous conclusions that FAA was absent in some mouse models. Second, circadian genes are not necessary for FEO timekeeping. Thus, another noncanonical timekeeping mechanism must exist in the FEO. Third, studies of mouse models have shown that signaling pathways involved in circadian timekeeping, reward (dopaminergic), and feeding and energy homeostasis can modulate, but are not necessary for, the expression of FAA. In sum, the approaches to date have been largely unsuccessful in discovering the timekeeping mechanism of the FEO. Moving forward, we propose the use of standardized and optimized experimental protocols that focus on identifying genes that alter the period of FAA in mutant and engineered mouse models. This approach is likely to permit discovery of molecular components of the FEO timekeeping mechanism.
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Affiliation(s)
| | - Shin Yamazaki
- Department of Neuroscience, UT Southwestern Medical Center, Dallas, Texas
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10
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Kim M, de la Peña JB, Cheong JH, Kim HJ. Neurobiological Functions of the Period Circadian Clock 2 Gene, Per2. Biomol Ther (Seoul) 2018; 26:358-367. [PMID: 29223143 PMCID: PMC6029676 DOI: 10.4062/biomolther.2017.131] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 08/10/2017] [Accepted: 08/22/2017] [Indexed: 12/14/2022] Open
Abstract
Most organisms have adapted to a circadian rhythm that follows a roughly 24-hour cycle, which is modulated by both internal (clock-related genes) and external (environment) factors. In such organisms, the central nervous system (CNS) is influenced by the circadian rhythm of individual cells. Furthermore, the period circadian clock 2 (Per2) gene is an important component of the circadian clock, which modulates the circadian rhythm. Per2 is mainly expressed in the suprachiasmatic nucleus (SCN) of the hypothalamus as well as other brain areas, including the midbrain and forebrain. This indicates that Per2 may affect various neurobiological activities such as sleeping, depression, and addiction. In this review, we focus on the neurobiological functions of Per2, which could help to better understand its roles in the CNS.
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Affiliation(s)
- Mikyung Kim
- Department of Pharmacy, Uimyung Research Institute for Neuroscience, Sahmyook University, Seoul 01795, Republic of Korea
| | - June Bryan de la Peña
- Department of Pharmacy, Uimyung Research Institute for Neuroscience, Sahmyook University, Seoul 01795, Republic of Korea
| | - Jae Hoon Cheong
- Department of Pharmacy, Uimyung Research Institute for Neuroscience, Sahmyook University, Seoul 01795, Republic of Korea
| | - Hee Jin Kim
- Department of Pharmacy, Uimyung Research Institute for Neuroscience, Sahmyook University, Seoul 01795, Republic of Korea
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11
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Pendergast JS, Wendroth RH, Stenner RC, Keil CD, Yamazaki S. mPeriod2 Brdm1 and other single Period mutant mice have normal food anticipatory activity. Sci Rep 2017; 7:15510. [PMID: 29138421 PMCID: PMC5686205 DOI: 10.1038/s41598-017-15332-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 10/19/2017] [Indexed: 11/09/2022] Open
Abstract
Animals anticipate the timing of food availability via the food-entrainable oscillator (FEO). The anatomical location and timekeeping mechanism of the FEO are unknown. Several studies showed the circadian gene, Period 2, is critical for FEO timekeeping. However, other studies concluded that canonical circadian genes are not essential for FEO timekeeping. In this study, we re-examined the effects of the Per2Brdm1 mutation on food entrainment using methods that have revealed robust food anticipatory activity in other mutant lines. We examined food anticipatory activity, which is the output of the FEO, in single Period mutant mice. Single Per1, Per2, and Per3 mutant mice had robust food anticipatory activity during restricted feeding. In addition, we found that two different lines of Per2 mutant mice (ldc and Brdm1) anticipated restricted food availability. To determine if FEO timekeeping persisted in the absence of the food cue, we assessed activity during fasting. Food anticipatory (wheel-running) activity in all Period mutant mice was also robust during food deprivation. Together, our studies demonstrate that the Period genes are not necessary for the expression of food anticipatory activity.
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Affiliation(s)
- Julie S Pendergast
- Department of Biology, University of Kentucky, Lexington, Kentucky, USA. .,Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA.
| | - Robert H Wendroth
- Department of Biology, University of Kentucky, Lexington, Kentucky, USA
| | - Rio C Stenner
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA
| | - Charles D Keil
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA
| | - Shin Yamazaki
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA.,Department of Neuroscience, University of Texas Southwestern, Dallas, TX, USA
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12
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Tan HY, Steyn FJ, Huang L, Cowley M, Veldhuis JD, Chen C. Hyperphagia in male melanocortin 4 receptor deficient mice promotes growth independently of growth hormone. J Physiol 2016; 594:7309-7326. [PMID: 27558671 DOI: 10.1113/jp272770] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 08/22/2016] [Indexed: 12/13/2022] Open
Abstract
KEY POINTS Loss of function of the melanocortin 4 receptor (MC4R) results in hyperphagia, obesity and increased growth. Despite knowing that MC4Rs control food intake, we are yet to understand why defects in the function of the MC4R receptor contribute to rapid linear growth. We show that hyperphagia following germline loss of MC4R in male mice promotes growth while suppressing the growth hormone-insulin-like growth factor-1 (GH-IGF-1) axis. We propose that hyperinsulinaemia promotes growth while suppressing the GH-IGF-1 axis. It is argued that physiological responses essential to maintain energy flux override conventional mechanisms of pubertal growth to promote the storage of excess energy while ensuring growth. ABSTRACT Defects in melanocortin-4-receptor (MC4R) signalling result in hyperphagia, obesity and increased growth. Clinical observations suggest that loss of MC4R function may enhance growth hormone (GH)-mediated growth, although this remains untested. Using male mice with germline loss of the MC4R, we assessed pulsatile GH release and insulin-like growth factor-1 (IGF-1) production and/or release relative to pubertal growth. We demonstrate early-onset suppression of GH release in rapidly growing MC4R deficient (MC4RKO) mice, confirming that increased linear growth in MC4RKO mice does not occur in response to enhanced activation of the GH-IGF-1 axis. The progressive suppression of GH release in MC4RKO mice occurred alongside increased adiposity and the progressive worsening of hyperphagia-associated hyperinsulinaemia. We next prevented hyperphagia in MC4RKO mice through restricting calorie intake in these mice to match that of wild-type (WT) littermates. Pair feeding of MC4RKO mice did not prevent increased adiposity, but attenuated hyperinsulinaemia, recovered GH release, and normalized linear growth rate to that seen in pair-fed WT littermate controls. We conclude that the suppression of GH release in MC4RKO mice occurs independently of increased adipose mass, and is a consequence of hyperphagia-associated hyperinsulinaemia. It is proposed that physiological responses essential to maintain energy flux (hyperinsulinaemia and the suppression of GH release) override conventional mechanisms of pubertal growth to promote the storage of excess energy while ensuring growth. Implications of these findings are likely to extend beyond individuals with defects in MC4R signalling, encompassing physiological changes central to mechanisms of growth and energy homeostasis universal to hyperphagia-associated childhood-onset obesity.
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Affiliation(s)
- H Y Tan
- School of Biomedical Sciences, University of Queensland, Brisbane, Queensland, Australia
| | - F J Steyn
- School of Biomedical Sciences, University of Queensland, Brisbane, Queensland, Australia.,The University of Queensland Centre for Clinical Research, The University of Queensland, Brisbane, Queensland, Australia
| | - L Huang
- School of Biomedical Sciences, University of Queensland, Brisbane, Queensland, Australia
| | - M Cowley
- Department of Physiology, Monash University, Melbourne, Victoria, Australia
| | - J D Veldhuis
- Department of Medicine, Endocrine Research Unit, Mayo School of Graduate Medical Education, Clinical Translational Science Center, Mayo Clinic, Rochester, MN, USA
| | - C Chen
- School of Biomedical Sciences, University of Queensland, Brisbane, Queensland, Australia
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13
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Unique food-entrained circadian rhythm in cysteine414-alanine mutant mCRY1 transgenic mice. Sleep Biol Rhythms 2016; 14:261-269. [PMID: 27441028 PMCID: PMC4932127 DOI: 10.1007/s41105-016-0050-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 01/07/2016] [Indexed: 11/05/2022]
Abstract
Food availability is a potent environmental cue that directs circadian locomotor activity in rodents. Daily scheduled restricted feeding (RF), in which the food available time is restricted for several hours each day, elicits anticipatory activity. This food-anticipatory activity (FAA) is controlled by a food-entrainable oscillator (FEO) that is distinct from the suprachiasmatic nucleus (SCN), the master pacemaker in mammals. In an earlier report, we described generation of transgenic (Tg) mice ubiquitously overexpressing cysteine414-alanine mutant mCRY1. The Tg mice displayed long locomotor free-running periods (approximately 28 h) with rhythm splitting. Furthermore, their locomotor activity immediately re-adjusted to the advance of light–dark cycles (LD), suggesting some disorder in the coupling of SCN neurons. The present study examined the restricted feeding cycle (RF)-induced entrainment of locomotor activity in Tg mice in various light conditions. In LD, wild-type controls showed both FAA and LD-entrained activities. In Tg mice, almost all activity was eventually consolidated to a single bout before the feeding time. The result suggests a possibility that in Tg mice the feeding cycle dominates the LD cycle as an entrainment agent. In constant darkness (DD), wild-type mice exhibited robust free-run activity and FAA during RF. For Tg mice, only the rhythm entrained to RF was observed in DD. Furthermore, after returning to free feeding, the free-run started from the RF-entrained phase. These results suggest that the SCN of Tg mice is entrainable to RF and that the mCRY1 mutation alters the sensitivity of SCN to the cycle of nonphotic zeitgebers.
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Delezie J, Dumont S, Sandu C, Reibel S, Pevet P, Challet E. Rev-erbα in the brain is essential for circadian food entrainment. Sci Rep 2016; 6:29386. [PMID: 27380954 PMCID: PMC4933951 DOI: 10.1038/srep29386] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 06/20/2016] [Indexed: 01/07/2023] Open
Abstract
Foraging is costly in terms of time and energy. An endogenous food-entrainable system allows anticipation of predictable changes of food resources in nature. Yet the molecular mechanism that controls food anticipation in mammals remains elusive. Here we report that deletion of the clock component Rev-erbα impairs food entrainment in mice. Rev-erbα global knockout (GKO) mice subjected to restricted feeding showed reduced elevations of locomotor activity and body temperature prior to mealtime, regardless of the lighting conditions. The failure to properly anticipate food arrival was accompanied by a lack of phase-adjustment to mealtime of the clock protein PERIOD2 in the cerebellum, and by diminished expression of phosphorylated ERK 1/2 (p-ERK) during mealtime in the mediobasal hypothalamus and cerebellum. Furthermore, brain-specific knockout (BKO) mice for Rev-erbα display a defective suprachiasmatic clock, as evidenced by blunted daily activity under a light-dark cycle, altered free-running rhythm in constant darkness and impaired clock gene expression. Notably, brain deletion of Rev-erbα totally prevented food-anticipatory behaviour and thermogenesis. In response to restricted feeding, brain deletion of Rev-erbα impaired changes in clock gene expression in the hippocampus and cerebellum, but not in the liver. Our findings indicate that Rev-erbα is required for neural network-based prediction of food availability.
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Affiliation(s)
- Julien Delezie
- Regulation of circadian clocks team, Institute of Cellular and Integrative Neurosciences, UPR3212, Centre National de la Recherche Scientifique, University of Strasbourg, France
| | - Stéphanie Dumont
- Regulation of circadian clocks team, Institute of Cellular and Integrative Neurosciences, UPR3212, Centre National de la Recherche Scientifique, University of Strasbourg, France
| | - Cristina Sandu
- Regulation of circadian clocks team, Institute of Cellular and Integrative Neurosciences, UPR3212, Centre National de la Recherche Scientifique, University of Strasbourg, France
| | - Sophie Reibel
- Chronobiotron, UMS3415, CNRS, University of Strasbourg, France
| | - Paul Pevet
- Regulation of circadian clocks team, Institute of Cellular and Integrative Neurosciences, UPR3212, Centre National de la Recherche Scientifique, University of Strasbourg, France
| | - Etienne Challet
- Regulation of circadian clocks team, Institute of Cellular and Integrative Neurosciences, UPR3212, Centre National de la Recherche Scientifique, University of Strasbourg, France
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15
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Chavan R, Feillet C, Costa SSF, Delorme JE, Okabe T, Ripperger JA, Albrecht U. Liver-derived ketone bodies are necessary for food anticipation. Nat Commun 2016; 7:10580. [PMID: 26838474 PMCID: PMC4742855 DOI: 10.1038/ncomms10580] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2015] [Accepted: 12/30/2015] [Indexed: 12/16/2022] Open
Abstract
The circadian system has endowed animals with the ability to anticipate recurring food availability at particular times of day. As daily food anticipation (FA) is independent of the suprachiasmatic nuclei, the central pacemaker of the circadian system, questions arise of where FA signals originate and what role components of the circadian clock might play. Here we show that liver-specific deletion of Per2 in mice abolishes FA, an effect that is rescued by viral overexpression of Per2 in the liver. RNA sequencing indicates that Per2 regulates β-hydroxybutyrate (βOHB) production to induce FA leading to the conclusion that liver Per2 is important for this process. Unexpectedly, we show that FA originates in the liver and not in the brain. However, manifestation of FA involves processing of the liver-derived βOHB signal in the brain, indicating that the food-entrainable oscillator is not located in a single tissue but is of systemic nature.
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Affiliation(s)
- Rohit Chavan
- Department of Biology, Unit of Biochemistry, University of Fribourg, Fribourg 1700, Switzerland
| | - Céline Feillet
- Department of Biology, Unit of Biochemistry, University of Fribourg, Fribourg 1700, Switzerland
| | - Sara S Fonseca Costa
- Department of Biology, Unit of Biochemistry, University of Fribourg, Fribourg 1700, Switzerland
| | - James E Delorme
- Department of Biology, Unit of Biochemistry, University of Fribourg, Fribourg 1700, Switzerland
| | - Takashi Okabe
- Department of Biology, Unit of Biochemistry, University of Fribourg, Fribourg 1700, Switzerland
| | - Jürgen A Ripperger
- Department of Biology, Unit of Biochemistry, University of Fribourg, Fribourg 1700, Switzerland
| | - Urs Albrecht
- Department of Biology, Unit of Biochemistry, University of Fribourg, Fribourg 1700, Switzerland
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Munn RGK, Tyree SM, McNaughton N, Bilkey DK. The frequency of hippocampal theta rhythm is modulated on a circadian period and is entrained by food availability. Front Behav Neurosci 2015; 9:61. [PMID: 25814943 PMCID: PMC4356069 DOI: 10.3389/fnbeh.2015.00061] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 02/23/2015] [Indexed: 11/13/2022] Open
Abstract
The hippocampal formation plays a critical role in the generation of episodic memory. While the encoding of the spatial and contextual components of memory have been extensively studied, how the hippocampus encodes temporal information, especially at long time intervals, is less well understood. The activity of place cells in hippocampus has previously been shown to be modulated at a circadian time-scale, entrained by a behavioral stimulus, but not entrained by light. The experimental procedures used in the previous study of this phenomenon, however, necessarily conflated two alternative entraining stimuli, the exposure to the recording environment and the availability of food, making it impossible to distinguish between these possibilities. Here we demonstrate that the frequency of theta-band hippocampal EEG varies with a circadian period in freely moving animals and that this periodicity mirrors changes in the firing rate of hippocampal neurons. Theta activity serves, therefore, as a proxy of circadian-modulated hippocampal neuronal activity. We then demonstrate that the frequency of hippocampal theta driven by stimulation of the reticular formation also varies with a circadian period. Because this effect can be observed without having to feed the animal to encourage movement we were able to identify what stimulus entrains the circadian oscillation. We show that with reticular-activated recordings started at various times of the day the frequency of theta varies quasi-sinusoidally with a 25 h period and phase-aligned when referenced to the animal’s regular feeding time, but not the recording start time. Furthermore, we show that theta frequency consistently varied with a circadian period when the data obtained from repeated recordings started at various times of the day were referenced to the start of food availability in the recording chamber. This pattern did not occur when data were referenced to the start of the recording session or to the actual time of day when this was not also related to feeding time. This double dissociation demonstrates that hippocampal theta is modulated with a circadian timescale, and that this modulation is strongly entrained by food. One interpretation of this finding is that the hippocampus is responsive to a food entrainable oscillator (FEO) that might modulate foraging behavior over circadian periods.
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Affiliation(s)
- Robert G K Munn
- Department of Psychology, University of Otago Dunedin, New Zealand ; Department of Neurobiology, Stanford University Stanford, CA, USA
| | - Susan M Tyree
- Department of Psychology, University of Otago Dunedin, New Zealand
| | - Neil McNaughton
- Department of Psychology, University of Otago Dunedin, New Zealand
| | - David K Bilkey
- Department of Psychology, University of Otago Dunedin, New Zealand
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Gallardo CM, Hsu CT, Gunapala KM, Parfyonov M, Chang CH, Mistlberger RE, Steele AD. Behavioral and neural correlates of acute and scheduled hunger in C57BL/6 mice. PLoS One 2014; 9:e95990. [PMID: 24806659 PMCID: PMC4012955 DOI: 10.1371/journal.pone.0095990] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Accepted: 04/01/2014] [Indexed: 01/11/2023] Open
Abstract
In rodents, daily feeding schedules induce food anticipatory activity (FAA) rhythms with formal properties suggesting mediation by food-entrained circadian oscillators (FEOs). The search for the neuronal substrate of FEOs responsible for FAA is an active area of research, but studies spanning several decades have yet to identify unequivocally a brain region required for FAA. Variability of results across studies leads to questions about underlying biology versus methodology. Here we describe in C57BL/6 male mice the effects of varying the ‘dose’ of caloric restriction (0%, 60%, 80%, 110%) on the expression of FAA as measured by a video-based analysis system, and on the induction of c-Fos in brain regions that have been implicated in FAA. We determined that more severe caloric restriction (60%) leads to a faster onset of FAA with increased magnitude. Using the 60% caloric restriction, we found little evidence for unique signatures of neuronal activation in the brains of mice anticipating a daily mealtime compared to mice that were fasted acutely or fed ad-libitum–even in regions such as the dorsomedial and ventrolateral hypothalamus, nucleus accumbens, and cerebellum that have previously been implicated in FAA. These results underscore the importance of feeding schedule parameters in determining quantitative features of FAA in mice, and demonstrate dissociations between behavioral FAA and neural activity in brain areas thought to harbor FEOs or participate in their entrainment or output.
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Affiliation(s)
- Christian M. Gallardo
- Division of Biology, California Institute of Technology, Pasadena, California, United States of America
| | - Cynthia T. Hsu
- Division of Biology, California Institute of Technology, Pasadena, California, United States of America
| | - Keith M. Gunapala
- Division of Biology, California Institute of Technology, Pasadena, California, United States of America
| | - Maksim Parfyonov
- Department of Psychology, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Chris H. Chang
- W.M. Keck Science Department, Claremont McKenna College, Pitzer College, Scripps College, Claremont, California, United States of America
| | - Ralph E. Mistlberger
- Department of Psychology, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Andrew D. Steele
- Division of Biology, California Institute of Technology, Pasadena, California, United States of America
- Biological Sciences Department, California State Polytechnic University Pomona, Pomona, California, United States of America
- * E-mail:
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Gallistel CR, Tucci V, Nolan PM, Schachner M, Jakovcevski I, Kheifets A, Barboza L. Cognitive assessment of mice strains heterozygous for cell-adhesion genes reveals strain-specific alterations in timing. Philos Trans R Soc Lond B Biol Sci 2014; 369:20120464. [PMID: 24446498 PMCID: PMC3895989 DOI: 10.1098/rstb.2012.0464] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
We used a fully automated system for the behavioural measurement of physiologically meaningful properties of basic mechanisms of cognition to test two strains of heterozygous mutant mice, Bfc (batface) and L1, and their wild-type littermate controls. Both of the target genes are involved in the establishment and maintenance of synapses. We find that the Bfc heterozygotes show reduced precision in their representation of interval duration, whereas the L1 heterozygotes show increased precision. These effects are functionally specific, because many other measures made on the same mice are unaffected, namely: the accuracy of matching temporal investment ratios to income ratios in a matching protocol, the rate of instrumental and classical conditioning, the latency to initiate a cued instrumental response, the trials on task and the impulsivity in a switch paradigm, the accuracy with which mice adjust timed switches to changes in the temporal constraints, the days to acquisition, and mean onset time and onset variability in the circadian anticipation of food availability.
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Affiliation(s)
| | - Valter Tucci
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, via Morego, 30, Genova 16163, Italy
| | - Patrick M. Nolan
- MRC Harwell, Harwell Science and Innovation Campus, Oxfordshire OX11 0RD, UK
| | - Melitta Schachner
- Departments of Genetics and Neurobiology, D251 Nelson Labs, 604 Allison Road, Piscataway, NJ 08854-6999, USA
| | - Igor Jakovcevski
- Zentrum für Molekulare Neurobiologie, Universitaetskrankenhaus Hamburg-Eppendorf, Falkenried 94, Hamburg D20251, Germany
| | - Aaron Kheifets
- Department of Psychology, Rutgers University, 152 Frelinghuysen Rd, Piscataway, NJ 08854-8020, USA
| | - Luendro Barboza
- Department of Psychology, Rutgers University, 152 Frelinghuysen Rd, Piscataway, NJ 08854-8020, USA
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Takasu NN, Kurosawa G, Tokuda IT, Mochizuki A, Todo T, Nakamura W. Circadian regulation of food-anticipatory activity in molecular clock-deficient mice. PLoS One 2012; 7:e48892. [PMID: 23145013 PMCID: PMC3492221 DOI: 10.1371/journal.pone.0048892] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Accepted: 10/03/2012] [Indexed: 12/13/2022] Open
Abstract
In the mammalian brain, the suprachiasmatic nucleus (SCN) of the anterior hypothalamus is considered to be the principal circadian pacemaker, keeping the rhythm of most physiological and behavioral processes on the basis of light/dark cycles. Because restriction of food availability to a certain time of day elicits anticipatory behavior even after ablation of the SCN, such behavior has been assumed to be under the control of another circadian oscillator. According to recent studies, however, mutant mice lacking circadian clock function exhibit normal food-anticipatory activity (FAA), a daily increase in locomotor activity preceding periodic feeding, suggesting that FAA is independent of the known circadian oscillator. To investigate the molecular basis of FAA, we examined oscillatory properties in mice lacking molecular clock components. Mice with SCN lesions or with mutant circadian periods were exposed to restricted feeding schedules at periods within and outside circadian range. Periodic feeding led to the entrainment of FAA rhythms only within a limited circadian range. Cry1(-/-) mice, which are known to be a "short-period mutant," entrained to a shorter period of feeding cycles than did Cry2(-/-) mice. This result indicated that the intrinsic periods of FAA rhythms are also affected by Cry deficiency. Bmal1(-/-) mice, deficient in another essential element of the molecular clock machinery, exhibited a pre-feeding increase of activity far from circadian range, indicating a deficit in circadian oscillation. We propose that mice possess a food-entrainable pacemaker outside the SCN in which canonical clock genes such as Cry1, Cry2 and Bmal1 play essential roles in regulating FAA in a circadian oscillatory manner.
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Affiliation(s)
- Nana N. Takasu
- Laboratory of Oral Chronobiology, Graduate School of Dentistry, Osaka University, Osaka, Japan
| | - Gen Kurosawa
- Theoretical Biology Laboratory, RIKEN Advanced Science Institute, Wako, Japan
| | - Isao T. Tokuda
- Department of Micro System Technology, Ritsumeikan University, Shiga, Japan
| | - Atsushi Mochizuki
- Theoretical Biology Laboratory, RIKEN Advanced Science Institute, Wako, Japan
| | - Takeshi Todo
- Department of Radiation Biology and Medical Genetics, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Wataru Nakamura
- Laboratory of Oral Chronobiology, Graduate School of Dentistry, Osaka University, Osaka, Japan
- Precursory Research for Embryonic Science and Technology, Japan Science and Technology Agency, Kawaguchi, Japan
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Bouchard-Cannon P, Cheng HYM. Scheduled feeding alters the timing of the suprachiasmatic nucleus circadian clock in dexras1-deficient mice. Chronobiol Int 2012; 29:965-81. [PMID: 22928915 PMCID: PMC3707842 DOI: 10.3109/07420528.2012.707264] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Restricted feeding (RF) schedules are potent zeitgebers capable of entraining metabolic and hormonal rhythms in peripheral oscillators in anticipation of food. Behaviorally, this manifests in the form of food anticipatory activity (FAA) in the hours preceding food availability. Circadian rhythms of FAA are thought to be controlled by a food-entrainable oscillator (FEO) outside of the suprachiasmatic nucleus (SCN), the central circadian pacemaker in mammals. Although evidence suggests that the FEO and the SCN are capable of interacting functionally under RF conditions, the genetic basis of these interactions remains to be defined. In this study, using dexras1-deficient (dexras1(-/-)) mice, the authors examined whether Dexras1, a modulator of multiple inputs to the SCN, plays a role in regulating the effects of RF on activity rhythms and gene expression in the SCN. Daytime RF under 12L:12D or constant darkness (DD) resulted in potentiated (but less stable) FAA expression in dexras1(-/-) mice compared with wild-type (WT) controls. Under these conditions, the magnitude and phase of the SCN-driven activity component were greatly perturbed in the mutants. Restoration to ad libitum (AL) feeding revealed a stable phase displacement of the SCN-driven activity component of dexras1(-/-) mice by ~2 h in advance of the expected time. RF in the late night/early morning induced a long-lasting increase in the period of the SCN-driven activity component in the mutants but not the WT. At the molecular level, daytime RF advanced the rhythm of PER1, PER2, and pERK expression in the mutant SCN without having any effect in the WT. Collectively, these results indicate that the absence of Dexras1 sensitizes the SCN to perturbations resulting from restricted feeding.
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Period determination in the food-entrainable and methamphetamine-sensitive circadian oscillator(s). Proc Natl Acad Sci U S A 2012; 109:14218-23. [PMID: 22891330 DOI: 10.1073/pnas.1206213109] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Daily rhythmic processes are coordinated by circadian clocks, which are present in numerous central and peripheral tissues. In mammals, two circadian clocks, the food-entrainable oscillator (FEO) and methamphetamine-sensitive circadian oscillator (MASCO), are "black box" mysteries because their anatomical loci are unknown and their outputs are not expressed under normal physiological conditions. In the current study, the investigation of the timekeeping mechanisms of the FEO and MASCO in mice with disruption of all three paralogs of the canonical clock gene, Period, revealed unique and convergent findings. We found that both the MASCO and FEO in Per1(-/-)/Per2(-/-)/Per3(-/-) mice are circadian oscillators with unusually short (∼21 h) periods. These data demonstrate that the canonical Period genes are involved in period determination in the FEO and MASCO, and computational modeling supports the hypothesis that the FEO and MASCO use the same timekeeping mechanism or are the same circadian oscillator. Finally, these studies identify Per1(-/-)/Per2(-/-)/Per3(-/-) mice as a unique tool critical to the search for the elusive anatomical location(s) of the FEO and MASCO.
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Blum I, Lamont EW, Abizaid A. Competing clocks: Metabolic status moderates signals from the master circadian pacemaker. Neurosci Biobehav Rev 2012; 36:254-70. [DOI: 10.1016/j.neubiorev.2011.06.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2011] [Revised: 05/27/2011] [Accepted: 06/02/2011] [Indexed: 11/28/2022]
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