scholarly journals Gastrointestinal Vagal Afferents and Food Intake: Relevance of Circadian Rhythms

Nutrients ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 844
Author(s):  
Amanda J. Page
Keyword(s):  
Food Intake ◽  
Shift Work ◽  
Time Of Day ◽  
Meal Size ◽  
Vagal Afferents ◽  
Diurnal Rhythms ◽  
Dark Phase ◽  
Light Phase ◽  
Diet Induced Obesity ◽  
The Impact

Gastrointestinal vagal afferents (VAs) play an important role in food intake regulation, providing the brain with information on the amount and nutrient composition of a meal. This is processed, eventually leading to meal termination. The response of gastric VAs, to food-related stimuli, is under circadian control and fluctuates depending on the time of day. These rhythms are highly correlated with meal size, with a nadir in VA sensitivity and increase in meal size during the dark phase and a peak in sensitivity and decrease in meal size during the light phase in mice. These rhythms are disrupted in diet-induced obesity and simulated shift work conditions and associated with disrupted food intake patterns. In diet-induced obesity the dampened responses during the light phase are not simply reversed by reverting back to a normal diet. However, time restricted feeding prevents loss of diurnal rhythms in VA signalling in high fat diet-fed mice and, therefore, provides a potential strategy to reset diurnal rhythms in VA signalling to a pre-obese phenotype. This review discusses the role of the circadian system in the regulation of gastrointestinal VA signals and the impact of factors, such as diet-induced obesity and shift work, on these rhythms.

Use of orchiectomy and testosterone replacement to explore meal number-to-meal size relationship in male rats

1999 ◽  
Vol 276 (5) ◽  
pp. R1366-R1373 ◽  
Author(s):  
Jia-Ke Chai ◽  
Vladimir Blaha ◽  
Michael M. Meguid ◽  
Alessandro Laviano ◽  
Zhong-Jin Yang ◽  
...  
Keyword(s):  
Food Intake ◽  
Meal Size ◽  
Male Rats ◽  
Testosterone Replacement ◽  
Sham Operation ◽  
Dark Phase ◽  
Light Phase ◽  
Feeding Regulation ◽  
Size Relationship ◽  
Significant Change

Because food intake is a function of meal number and meal size and because gender-related hormones are involved in feeding regulation, we explored effects of orchiectomy and testosterone replacement on the relationship between meal number and size and changes in resulting feeding patterns in adult male rats, randomized into orchiectomy and sham-operation groups. A rat eater meter measured feeding indexes for 1 wk before and 2 wk after castration and during 8 days of testosterone replacement. Orchiectomy leads to an immediate change in the meal number-to-size relationship, resulting in 1) change in pattern of feeding; 2) a significant decrease in dark-phase meal number; 3) a significant increase in dark-phase meal size, but insufficient to offset decrease in meal number, so total food intake significantly decreased during dark phase; 4) no significant change in light-phase meal number; and 5) an increase in meal size leading to an increased food intake during light phase, which offset decreased food intake in dark cycle and resulted in no net significant change in food intake after orchiectomy. Testosterone replacement acutely reversed effects of orchiectomy on meal number-to-meal size relationship, restoring feeding pattern. Data suggest that androgens immediately influence the meal number-to-meal size relationship. The speed of onset seen after orchiectomy suggests that the influence of testosterone on food intake may also occur partially via a nongenomic effect.

scholarly journals Time matters: pathological effects of repeated psychosocial stress during the active, but not inactive, phase of male mice

2012 ◽  
Vol 215 (3) ◽  
pp. 425-437 ◽  
Author(s):  
Manuela S Bartlang ◽  
Inga D Neumann ◽  
David A Slattery ◽  
Nicole Uschold-Schmidt ◽  
Dominik Kraus ◽  
...  
Keyword(s):  
Social Preference ◽  
Active Phase ◽  
Time Of Day ◽  
Dark Phase ◽  
Light Phase ◽  
Immunological Parameters ◽  
Repeated Restraint Stress ◽  
Inactive Phase ◽  
Home Cage Activity

Recent findings in rats indicated that the physiological consequences of repeated restraint stress are dependent on the time of day of stressor exposure. To investigate whether this is also true for clinically more relevant psychosocial stressors and whether repeated stressor exposure during the light phase or dark phase is more detrimental for an organism, we exposed male C57BL/6 mice to social defeat (SD) across 19 days either in the light phase between Zeitgeber time (ZT)1 and ZT3 (SDL mice) or in the dark phase between ZT13 and ZT15 (SDD mice). While SDL mice showed a prolonged increase in adrenal weight and an attenuated adrenal responsiveness to ACTHin vitroafter stressor termination, SDD mice showed reduced dark phase home-cage activity on observation days 7, 14, and 20, flattening of the diurnal corticosterone rhythm, lack of social preference, and higherin vitroIFNγ secretion from mesenteric lymph node cells on day 20/21. Furthermore, the colitis-aggravating effect of SD was more pronounced in SDD than SDL mice following dextran sulfate sodium treatment. In conclusion, the present findings demonstrate that repeated SD effects on behavior, physiology, and immunology strongly depend on the time of day of stressor exposure. Whereas physiological parameters were more affected by SD during the light/inactive phase of mice, behavioral and immunological parameters were more affected by SD during the dark phase. Our results imply that repeated daily SD exposure has a more negative outcome when applied during the dark/active phase. By contrast, the minor physiological changes seen in SDL mice might represent beneficial adaptations preventing the formation of those maladaptive consequences.

scholarly journals Intrameal Hepatic Portal and Intraperitoneal Infusions of Glucagon-Like Peptide-1 Reduce Spontaneous Meal Size in the Rat via Different Mechanisms

Endocrinology ◽  
2008 ◽  
Vol 150 (3) ◽  
pp. 1174-1181 ◽  
Author(s):  
Elisabeth B. Rüttimann ◽  
Myrtha Arnold ◽  
Jacquelien J. Hillebrand ◽  
Nori Geary ◽  
Wolfgang Langhans
Keyword(s):  
Food Intake ◽  
Vena Cava ◽  
Meal Size ◽  
Dark Phase ◽  
Hepatic Portal Vein ◽  
Vagal Afferent ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1 ◽  
Hepatic Portal ◽  
Afferent Signaling

Peripheral administration of glucagon-like peptide (GLP)-1 reduces food intake in animals and humans, but the sites and mechanism of this effect and its physiological significance are not yet clear. To investigate these issues, we prepared rats with chronic catheters and infused GLP-1 (0.2 ml/min; 2.5 or 5.0 min) during the first spontaneous dark-phase meals. Infusions were remotely triggered 2–3 min after meal onset. Hepatic portal vein (HPV) infusion of 1.0 or 3.0 (but not 0.33) nmol/kg GLP-1 reduced the size of the ongoing meal compared with vehicle without affecting the subsequent intermeal interval, the size of subsequent meals, or cumulative food intake. In double-cannulated rats, HPV and vena cava infusions of 1.0 nmol/kg GLP-1 reduced meal size similarly. HPV GLP-1 infusions of 1.0 nmol/kg GLP-1 also reduced meal size similarly in rats with subdiaphragmatic vagal deafferentations and in sham-operated rats. Finally, HPV and ip infusions of 10 nmol/kg GLP-1 reduced meal size similarly in sham-operated rats, but only HPV GLP-1 reduced meal size in subdiaphragmatic vagal deafferentation rats. These data indicate that peripherally infused GLP-1 acutely and specifically reduces the size of ongoing meals in rats and that the satiating effect of ip, but not iv, GLP-1 requires vagal afferent signaling. The findings suggest that iv GLP-1 infusions do not inhibit eating via hepatic portal or hepatic GLP-1 receptors but may act directly on the brain. Intrameal hepatic portal and intraperitoneal (IP) infusions of GLP-1 reduce meal size in rats, but only IP GLP-1 requires vagal afferent signaling for this effect.

scholarly journals Fluoxetine Mimics the Anorectic Action of Estrogen and Its Regulation of Circadian Feeding in Ovariectomized Female Rats

Nutrients ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 849 ◽  
Author(s):  
Yuri Nishimura ◽  
Kaori Mabuchi ◽  
Natsumi Omura ◽  
Ayako Igarashi ◽  
Megumi Miura ◽  
...  
Keyword(s):  
Food Intake ◽  
Selective Serotonin Reuptake Inhibitors ◽  
Body Weight Gain ◽  
Treated Group ◽  
Female Rats ◽  
Ovariectomized Rats ◽  
Dark Phase ◽  
Light Phase ◽  
Serotonergic Neurons ◽  
Fos Expression

Our previous study demonstrated that chronic estrogen replacement in ovariectomized rats reduces food intake and augments c-Fos expression in the suprachiasmatic nucleus (SCN), specifically during the light phase. Here, we hypothesized that serotonergic neurons in the central nervous system (CNS), which have anorectic action and play a role in regulating circadian rhythm, mediate the light phase-specific anorectic action of estrogen, and that selective serotonin reuptake inhibitors (SSRIs) mimic the hypophagic action of estrogen. Female Wistar rats were ovariectomized and treated with estradiol (E2) or cholesterol by subcutaneously implanting a silicon capsule containing E2 or cholesterol. Then, half of the cholesterol-treated rats were injected with the SSRI fluoxetine (5 mg/kg) (FLX group), while the remaining rats in the cholesterol-treated group (CON group) and all those in the E2 group were injected with saline subcutaneously twice daily at the onsets of the light and dark phases. Both E2 and FLX reduced food intake during the light phase but not the dark phase, and reduced body weight gain. In addition, both E2 and FLX augmented the c-Fos expression in the SCN, specifically during the light phase. These data indicate that FLX exerts estrogen-like antiobesity and hypophagic actions by modifying circadian feeding patterns, and suggest that estrogen regulates circadian feeding rhythm via serotonergic neurons in the CNS.

scholarly journals Dawn to Dusk: Diurnal Rhythm of the Immune Response in Rainbow Trout (Oncorhynchus Mykiss)

Biology ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 8 ◽  
Author(s):  
Ruth Montero ◽  
Joanna Ewa Strzelczyk ◽  
Justin Tze Ho Chan ◽  
Marieke Verleih ◽  
Alexander Rebl ◽  
...  
Keyword(s):  
Immune Response ◽  
Rainbow Trout ◽  
Phagocytic Activity ◽  
Myeloid Cells ◽  
Head Kidney ◽  
Time Of Day ◽  
Aeromonas Salmonicida ◽  
Diurnal Rhythms ◽  
Dark Phase ◽  
Immune Competence

The daily change of light and dark periods influences different physiological processes including feeding, resting and locomotor activity. Previously, several studies on mammalian models revealed a strong link between day-night rhythms and key immunological parameters. Since teleost fishes possess innate and adaptive immune responses like those observed in higher vertebrates, we aimed to elucidate how changes in light-dark cycles shape the immune system of fish. Using the rainbow trout laboratory model, we investigated the link between diurnal rhythms and immune competence of fish. Initially, the cell composition and phagocytic activity of leukocytes was analyzed in the circulation as well as in the head kidney, the functional ortholog of mammalian bone marrow. Once the baseline was established, we evaluated the ability of fish to respond to a bacterial stimulus, as well as the changes in antimicrobial activity of the serum. Our results suggest increased immune competence during the day, manifested by the higher presence of myeloid cells in the circulation; increased overall phagocytic activity; and higher capacity of the sera to inhibit the growth of Aeromonas salmonicida. Notably, our flow cytometric analysis identified the myeloid cells as the major population influenced by the time of day, whereas IgM+ B cells and thrombocytes did not vary in a significant manner. Interestingly, the presence of myeloid cells in blood and head kidney followed complementary trends. Thus, while we observed the highest number of myeloid cells in the blood during early morning, we witnessed a reverse trend in the head kidney, suggesting a homing of myeloid cells to reservoir niches with the onset of the dark phase. Further, the presence of myeloid cells was mirrored in the expression of the proinflammatory marker tnfa as well as in the number of leukocytes recruited to the peritoneal cavity in the peritonitis model of inflammation. Overall, the data suggest a connection between diurnal rhythms and the immune response of rainbow trout and highlight the relevance of rhythmicity and its influence on experimental work in the field of fish chronoimmunology.

NMDA channels control meal size via central vagal afferent terminals

2005 ◽  
Vol 289 (5) ◽  
pp. R1504-R1511 ◽  
Author(s):  
B. R. Gillespie ◽  
G. A. Burns ◽  
R. C. Ritter
Keyword(s):  
Food Intake ◽  
Ion Channel ◽  
Nmda Receptors ◽  
Higher Order ◽  
Meal Size ◽  
Vagal Afferents ◽  
Sucrose Intake ◽  
Mk 801 ◽  
Vagal Afferent ◽  
Afferent Terminals

The N-methyl-d-aspartate (NMDA) ion channel blocker MK-801 administered systemically or as a nanoliter injection into the nucleus of the solitary tract (NTS), increases meal size. Furthermore, we have observed that ablation of the NTS abolishes increased meal size following systemic injection of dizocilpine (MK-801) and that MK-801-induced increases in intake are attenuated in rats pretreated with capsaicin to destroy small, unmyelinated, primary afferent neurons. These findings led us to hypothesize that NMDA receptors on central vagal afferent terminals or on higher-order NTS neurons innervated by these vagal afferents might mediate increased food intake. To evaluate this hypothesis, we examined 15% sucrose intake after 50-nl MK-801 injections ipsilateral or contralateral to unilateral nodose ganglion removal (ganglionectomy). On the side contralateral to ganglionectomy, vagal afferent terminals would be intact and functional, whereas ipsilateral to ganglionectomy vagal afferent terminals would be absent. Three additional control preparations also were included: 1) sham ganglionectomy and 2) subnodose vagotomy either contralateral or ipsilateral to NTS cannula placement. We found that rats with subnodose vagotomies increased their sucrose intake after injections of MK-801 compared with saline, regardless of whether injections were made contralateral (12.6 ± 0.2 vs. 9.6 ± 0.3 ml) or ipsilateral (14.2 ± 0.6 vs. 9.7 ± 0.4 ml) to vagotomy. Rats with NTS cannula placements contralateral to nodose ganglionectomy also increased their intake after MK-801 (12.2 ± 0.9 and 9.2 ± 1.1 ml for MK-801 and saline, respectively). However, rats with placements ipsilateral to ganglionectomy did not respond to MK-801 (8.0 ± 0.5 ml) compared with saline (8.3 ± 0.4 ml). We conclude that central vagal afferent terminals are necessary for increased food intake in response to NMDA ion channel blockade. The function of central vagal afferent processes or the activity of higher-order NTS neurons driven by vagal afferents may be modulated by NMDA receptors to control meal size.

scholarly journals Chronic ethanol consumption disrupts diurnal rhythms of hepatic glycogen metabolism in mice

2015 ◽  
Vol 308 (11) ◽  
pp. G964-G974 ◽  
Author(s):  
Uduak S. Udoh ◽  
Telisha M. Swain ◽  
Ashley N. Filiano ◽  
Karen L. Gamble ◽  
Martin E. Young ◽  
...  
Keyword(s):  
Glycogen Synthase ◽  
Control Diet ◽  
Glycogen Metabolism ◽  
Ethanol Consumption ◽  
Time Of Day ◽  
Chronic Ethanol ◽  
Diurnal Rhythms ◽  
Hepatic Glycogen ◽  
Chronic Ethanol Consumption ◽  
The Impact

Chronic ethanol consumption has been shown to significantly decrease hepatic glycogen content; however, the mechanisms responsible for this adverse metabolic effect are unknown. In this study, we examined the impact chronic ethanol consumption has on time-of-day-dependent oscillations (rhythms) in glycogen metabolism processes in the liver. For this, male C57BL/6J mice were fed either a control or ethanol-containing liquid diet for 5 wk, and livers were collected every 4 h for 24 h and analyzed for changes in various genes and proteins involved in hepatic glycogen metabolism. Glycogen displayed a robust diurnal rhythm in the livers of mice fed the control diet, with the peak occurring during the active (dark) period of the day. The diurnal glycogen rhythm was significantly altered in livers of ethanol-fed mice, with the glycogen peak shifted into the inactive (light) period and the overall content of glycogen decreased compared with controls. Chronic ethanol consumption further disrupted diurnal rhythms in gene expression (glycogen synthase 1 and 2, glycogenin, glucokinase, protein targeting to glycogen, and pyruvate kinase), total and phosphorylated glycogen synthase protein, and enzyme activities of glycogen synthase and glycogen phosphorylase, the rate-limiting enzymes of glycogen metabolism. In summary, these results show for the first time that chronic ethanol consumption disrupts diurnal rhythms in hepatic glycogen metabolism at the gene and protein level. Chronic ethanol-induced disruption in these daily rhythms likely contributes to glycogen depletion and disruption of hepatic energy homeostasis, a recognized risk factor in the etiology of alcoholic liver disease.

scholarly journals Food restriction, refeeding, and gastric fill fail to affect emesis in musk shrews

2010 ◽  
Vol 298 (1) ◽  
pp. G25-G30 ◽  
Author(s):  
Charles C. Horn ◽  
Liz Still ◽  
Christiana Fitzgerald ◽  
Mark I. Friedman
Keyword(s):  
Side Effects ◽  
Food Intake ◽  
Food Restriction ◽  
Area Postrema ◽  
Gastrointestinal Disease ◽  
Vagal Afferents ◽  
Neural Pathways ◽  
Chemotherapy Agent ◽  
Nausea And Emesis ◽  
The Impact

Nausea and emesis are common side effects of gastrointestinal disease. Reports indicate that ghrelin and endocannabinoids, agents that stimulate appetite, also reduce emesis evoked by chemotherapy treatment, which suggests that stimulation of feeding inhibits the emetic system. In the following study we conducted a more direct test of this hypothesis by determining the impact of manipulating the motivation to eat on emesis, using food restriction and refeeding. Emesis was induced in musk shrews, a commonly used animal model for emesis research, using the cancer chemotherapy agent cisplatin (20 mg/kg ip), nicotine (2 mg/kg sc), or motion (1 Hz, horizontal, 4-cm displacement), because these treatments are known to target separate emetic pathways: gut vagal afferents, area postrema, and vestibular pathways, respectively. Twenty-four hours of food restriction was sufficient to stimulate food intake, and 1 h of refeeding filled the stomach. The results indicate that food restriction, refeeding, and gastric fill had no significant effects on the amount of emesis produced by any of the emetic treatments tested here. This suggests that, although activation of the emetic system might have prominent effects on food intake, neural controls for feeding behavior do not significantly affect the neural pathways for emesis. These results may have implications for how we treat patients who experience a constellation of side effects, including nausea and emesis, since stimulating appetite may not necessarily inhibit emetic pathways.

scholarly journals Cyclophosphamide Depletes Ovarian Follicles in Mice During Both the Light and Dark Phases of the Circadian Cycle

2020 ◽  
Vol 17 (3) ◽  
pp. 11-17
Author(s):  
Benjamin Koch ◽  
Kristen Roosa
Keyword(s):  
Circadian Rhythm ◽  
Ovarian Reserve ◽  
Alkylating Agent ◽  
Single Injection ◽  
Ovarian Follicles ◽  
Dark Phase ◽  
Light Phase ◽  
Primordial Follicles ◽  
Ovarian Toxicity ◽  
The Impact

The alkylating agent cyclophosphamide (CY) is a potent ovarian toxicant. It damages growing follicles and causes premature activation and depletion of the resting follicles that constitute the ovarian reserve. While there is abundant information on the impact of CY on the ovary and its toxicity mechanisms, the influence of the circadian rhythm on ovarian toxicity has not been evaluated. To test the hypothesis that time of exposure affects ovarian toxicity of CY, C57BL/6 mice were treated with a single injection of CY (75 mg/kg) at either two hours after lights on (Zeitgeber time (ZT) 02) or two hours after lights off (ZT14). Toxicity was evaluated one week after treatment by counting ovarian follicles in histological sections. Fewer primordial follicles were counted in the ovaries of CY-treated animals at both treatment times, and fewer antral follicles were counted in the ovaries of animals treated at ZT02. There was no difference in the number of primordial follicles in the ovaries of CY-treated animals between the two treatment times. These results demonstrate that CY-induced depletion of the ovarian reserve occurs when mice are exposed early in the light phase and early in the circadian cycle’s dark phase. There is no impact of the circadian rhythm on follicle depletion by CY at these time points. KEYWORDS: Cyclophosphamide; ovary; circadian; ovarian follicles; toxicity; mouse; chronotherapy; alkylating agent

Time-of-day influence on exploratory behaviour of rats exposed to an unfamiliar environment

Behaviour ◽  
2014 ◽  
Vol 151 (14) ◽  
pp. 1943-1966 ◽  
Author(s):  
Cássio M. Loss ◽  
Sandro D. Córdova ◽  
Sidia Maria Callegari-Jacques ◽  
Diogo L. de Oliveira
Keyword(s):  
Principal Component ◽  
Time Of Day ◽  
Temporal Organization ◽  
Exploratory Behaviour ◽  
Dark Phase ◽  
Light Phase ◽  
Home Base ◽  
Plus Maze ◽  
Male Wistar Rats ◽  
Spatio Temporal

It is well known that rats exhibit elevated levels of activity during the dark phase and reduced levels during the light phase of the photoperiod cycle. However, the information about the influence of the time-of-day on the strategies used to explore the environment is still not understood. Here we tested the hypothesis that time-of-day influences the fine-scale exploratory behaviour of rats, measured in the open field (OF) test, and emotionality of rats, measured in the elevated plus maze (EPM) test. Adult male Wistar rats were subjected to the OF and EPM tests during Morning, Afternoon, or Evening sessions. In the OF, a principal component analysis (PCA) revealed that the Evening group exhibited longer duration of locomotion and rearing, and also higher distance travelled, trip length, inter-stop distance, number of stops and stops per trip compared to other groups. PCA also revealed that the Evening group exhibited shorter time spent at the home base, duration of locomotion along the perimeter and distance travelled along the perimeter compared to other groups. In the EPM test, there was no difference between the groups in any of the parameters evaluated. Our results indicate that the time-of-day may influence the spatio-temporal organization of exploration of rats subjected to unfamiliar environments. These alterations appear to be unrelated to differences in the emotional state of the animals.

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