scholarly journals Housing temperature affects the circadian rhythm of hepatic metabolism and clock genes

2020 ◽  
Vol 247 (2) ◽  
pp. 183-195
Author(s):  
Anjara Rabearivony ◽  
Huan Li ◽  
Shiyao Zhang ◽  
Siyu Chen ◽  
Xiaofei An ◽  
...  
Keyword(s):  
Circadian Rhythm ◽  
Clock Genes ◽  
Hepatic Metabolism ◽  
Serum Levels ◽  
Phase Changes ◽  
External Temperature ◽  
Glucose Levels ◽  
Circadian Oscillators ◽  
Housing Temperature ◽  
Advanced Phase

Environmental temperature remarkably impacts on metabolic homeostasis, raising a serious concern about the optimum housing temperature for translational studies. Recent studies suggested that mice should be housed slightly below their thermoneutral temperature (26°C). On the other hand, the external temperature, also known as a zeitgeber, can reset the circadian rhythm. However, whether housing temperature affects the circadian oscillators of the liver remains unknown. Therefore, we have compared the effect of two housing temperatures, namely 21°C (conventional; TC) and 26°C (thermoneutral; TN), on the circadian rhythms in mice. We found that the rhythmicity of food intake showed an advanced phase at TC, while the activity was more robust at TN, with a prolonged period onset. The serum levels of norepinephrine were remarkably induced at TC, but failed to oscillate rhythmically at both temperatures. Likewise, circulating glucose levels were increased but were non-rhythmic under TC. Both total cholesterol and triglycerides levels were induced at TN, but showed an advanced phase under TC. Additionally, the expression of hepatic metabolic genes and clock genes remained rhythmic at both temperatures, with the exception of G6Pase, Fasn, Cpt1a and Cry2, at TN. Nevertheless, the liver histology examination did not show any significant changes in response to housing temperature. Although the non-consistent trends of phase changes in each temperature, our results suggest a non-reductant role of temperature in mouse internal rhythmicity resetting. Thus, the temperature-controlled internal circadian synchronization within organs should be taken into consideration when optimizing housing temperature for mice.

scholarly journals Astrocytic Modulation of Neuronal Activity in the Suprachiasmatic Nucleus: Insights from Mathematical Modeling

2020 ◽  
Vol 35 (3) ◽  
pp. 287-301
Author(s):  
Natthapong Sueviriyapan ◽  
Chak Foon Tso ◽  
Erik D. Herzog ◽  
Michael A. Henson
Keyword(s):  
Circadian Rhythm ◽  
Suprachiasmatic Nucleus ◽  
Neuronal Activity ◽  
Clock Genes ◽  
Rhythmic Activity ◽  
Neuronal Population ◽  
Circadian Period ◽  
Circadian Oscillators ◽  
Bidirectional Interactions ◽  
The Impact

The suprachiasmatic nucleus (SCN) of the hypothalamus consists of a highly heterogeneous neuronal population networked together to allow precise and robust circadian timekeeping in mammals. While the critical importance of SCN neurons in regulating circadian rhythms has been extensively studied, the roles of SCN astrocytes in circadian system function are not well understood. Recent experiments have demonstrated that SCN astrocytes are circadian oscillators with the same functional clock genes as SCN neurons. Astrocytes generate rhythmic outputs that are thought to modulate neuronal activity through pre- and postsynaptic interactions. In this study, we developed an in silico multicellular model of the SCN clock to investigate the impact of astrocytes in modulating neuronal activity and affecting key clock properties such as circadian rhythmicity, period, and synchronization. The model predicted that astrocytes could alter the rhythmic activity of neurons via bidirectional interactions at tripartite synapses. Specifically, astrocyte-regulated extracellular glutamate was predicted to increase neuropeptide signaling from neurons. Consistent with experimental results, we found that astrocytes could increase the circadian period and enhance neural synchronization according to their endogenous circadian period. The impact of astrocytic modulation of circadian rhythm amplitude, period, and synchronization was predicted to be strongest when astrocytes had periods between 0 and 2 h longer than neurons. Increasing the number of neurons coupled to the astrocyte also increased its impact on period modulation and synchrony. These computational results suggest that signals that modulate astrocytic rhythms or signaling (e.g., as a function of season, age, or treatment) could cause disruptions in circadian rhythm or serve as putative therapeutic targets.

PENGARUH PEMBERIAN FRAKSI ETILASETAT KULIT UBI JALAR UNGU TERHADAP KADAR MALONDIALDEHID (MDA) SERUM MENCIT PUTIH JANTAN HIPERGLIKEMIA

2018 ◽  
Vol 8 (2) ◽  
pp. 144
Author(s):  
Ria Afrianti
Keyword(s):  
Blood Glucose ◽  
Statistical Analysis ◽  
Sweet Potato ◽  
Ethyl Acetate Fraction ◽  
Serum Levels ◽  
Negative Control ◽  
Control Group ◽  
Glucose Levels ◽  
Blood Glucose Levels ◽  
Purple Sweet Potato

This study aims to determine the effect giving of ethylacetate fraction of leather  purple sweet potato (Ipomoea batatas (L.) Lam, on levels of malondialdehyde (MDA) serum in mice hyperglicemia were induced with streptozocin dose of 50 mg/kgBW. Mice were divided into 5 groups, each group consisting of 3 tails, group I is a negative control, group II is a positive control, group III,IV and V is given ethylacetate fraction a dose of 100 mg/kgBW, 300 mg/kgBW, and 600 mg/kgBW. Ethyl Acetate Fraction leather purple sweet potato given orally for 15 days after the animal is declared hyperglicemia and measurement of blood glucose levels on 5, 10, and 15 day after giving test preparation in animal experiments. On the 16 day throughout the mice were taken serum levels measured malondialdehid. The statistical analysis results showed that giving of ethyl acetate fraction of leather purple sweet potato at a dose of 100 mg/kgBW, 300 mg/kgBW, and 600 mg/kgBW can lower blood glucose levels in mice hyperglycemia significantly (p<0.05). Malondialdehid levels on average in each group is 1.35 nmol/ml, 3.00 nmol/ml, 2.72 nmol/ml, 2.20 nmol/ml and 2.61 nmol/ml, the results of statistical analysis showed a decrease in melondialdehid serum levels were significantly (p<0.05), where a dose of 300 mg/kgBW is an effective dose for lowering blood glucose levels followed by decreased levels of malondialdehid which give effect approaching negative control.

scholarly journals Sex Differences in Circadian Clock Genes and Myocardial Infarction Susceptibility

2021 ◽  
Vol 8 (5) ◽  
pp. 53
Author(s):  
Ivana Škrlec ◽  
Jasminka Talapko ◽  
Martina Juzbašić ◽  
Robert Steiner
Keyword(s):  
Myocardial Infarction ◽  
Cardiovascular Disease ◽  
Circadian Rhythm ◽  
Single Nucleotide Polymorphisms ◽  
Clock Genes ◽  
P Value ◽  
Nucleotide Polymorphisms ◽  
Single Nucleotide ◽  
Biological Sex ◽  
Significant Difference

The growing body of evidence shows a significant difference in the circadian rhythm of cardiovascular disease based on biological sex. The incidence of cardiovascular disease varies between women and men. Additionally, biological sex is vital for the timely application of therapy—chronotherapy, which benefits both sexes. This study aimed to examine the potential difference of single nucleotide polymorphisms (SNPs) of the circadian rhythm genes ARNTL, CLOCK, CRY2 and PER2 in women and men with myocardial infarction. A cross-sectional study was conducted, including 200 patients with myocardial infarction. Altogether, ten single nucleotide polymorphisms in the ARNTL, CLOCK, CRY2 and PER2 genes were analyzed. The Chi-square test yielded statistically significant differences in CLOCK gene rs11932595 polymorphism in a recessive genotype model between women and men with a p-value of 0.03 and an odds ratio 2.66, and a corresponding 95% confidence interval of 1.07 to 6.66. Other analyzed polymorphisms of the circadian rhythm genes ARNTL, CRY2, and PER2 did not significantly differ between the sexes. According to the study’s current results, the CLOCK gene’s genetic variability might affect myocardial infarction concerning biological sex.

scholarly journals Alteration of circadian machinery in monocytes underlies chronic kidney disease-associated cardiac inflammation and fibrosis

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yuya Yoshida ◽  
Naoya Matsunaga ◽  
Takaharu Nakao ◽  
Kengo Hamamura ◽  
Hideaki Kondo ◽  
...  
Keyword(s):  
Chronic Kidney Disease ◽  
Kidney Disease ◽  
Clock Genes ◽  
Serum Levels ◽  
Serum Retinol ◽  
Cardiac Inflammation ◽  
Physiological Processes ◽  
G Protein Coupled ◽  
Clock Protein

AbstractDysfunction of the circadian clock has been implicated in the pathogenesis of cardiovascular disease. The CLOCK protein is a core molecular component of the circadian oscillator, so that mice with a mutated Clock gene (Clk/Clk) exhibit abnormal rhythms in numerous physiological processes. However, here we report that chronic kidney disease (CKD)-induced cardiac inflammation and fibrosis are attenuated in Clk/Clk mice even though they have high blood pressure and increased serum angiotensin II levels. A search for the underlying cause of the attenuation of heart disorder in Clk/Clk mice with 5/6 nephrectomy (5/6Nx) led to identification of the monocytic expression of G protein-coupled receptor 68 (GPR68) as a risk factor of CKD-induced inflammation and fibrosis of heart. 5/6Nx induces the expression of GPR68 in circulating monocytes via altered CLOCK activation by increasing serum levels of retinol and its binding protein (RBP4). The high-GPR68-expressing monocytes have increased potential for producing inflammatory cytokines, and their cardiac infiltration under CKD conditions exacerbates inflammation and fibrosis of heart. Serum retinol and RBP4 levels in CKD patients are also sufficient to induce the expression of GPR68 in human monocytes. Our present study reveals an uncovered role of monocytic clock genes in CKD-induced heart failure.

scholarly journals Circadian Rhythm: Potential Therapeutic Target for Atherosclerosis and Thrombosis

2021 ◽  
Vol 22 (2) ◽  
pp. 676
Author(s):  
Andy W. C. Man ◽  
Huige Li ◽  
Ning Xia
Keyword(s):  
Circadian Rhythm ◽  
Cardiovascular Diseases ◽  
Circadian Rhythms ◽  
Circadian Clock ◽  
Therapeutic Target ◽  
Environmental Changes ◽  
Clock Genes ◽  
Vascular System ◽  
Peripheral Tissues ◽  
Inflammatory Processes

Every organism has an intrinsic biological rhythm that orchestrates biological processes in adjusting to daily environmental changes. Circadian rhythms are maintained by networks of molecular clocks throughout the core and peripheral tissues, including immune cells, blood vessels, and perivascular adipose tissues. Recent findings have suggested strong correlations between the circadian clock and cardiovascular diseases. Desynchronization between the circadian rhythm and body metabolism contributes to the development of cardiovascular diseases including arteriosclerosis and thrombosis. Circadian rhythms are involved in controlling inflammatory processes and metabolisms, which can influence the pathology of arteriosclerosis and thrombosis. Circadian clock genes are critical in maintaining the robust relationship between diurnal variation and the cardiovascular system. The circadian machinery in the vascular system may be a novel therapeutic target for the prevention and treatment of cardiovascular diseases. The research on circadian rhythms in cardiovascular diseases is still progressing. In this review, we briefly summarize recent studies on circadian rhythms and cardiovascular homeostasis, focusing on the circadian control of inflammatory processes and metabolisms. Based on the recent findings, we discuss the potential target molecules for future therapeutic strategies against cardiovascular diseases by targeting the circadian clock.

scholarly journals Vapor flux and recrystallization during dry snow metamorphism under a steady temperature gradient as observed by time-lapse micro-tomography

2012 ◽  
Vol 6 (5) ◽  
pp. 1141-1155 ◽  
Author(s):  
B. R. Pinzer ◽  
M. Schneebeli ◽  
T. U. Kaempfer
Keyword(s):  
Temperature Gradient ◽  
Physical Properties ◽  
Time Lapse ◽  
Phase Changes ◽  
External Temperature ◽  
Vapor Flux ◽  
Snow Metamorphism ◽  
Diffusion Enhancement ◽  
Micro Tomography ◽  
Snow Microstructure

Abstract. Dry snow metamorphism under an external temperature gradient is the most common type of recrystallization of snow on the ground. The changes in snow microstructure modify the physical properties of snow, and therefore an understanding of this process is essential for many disciplines, from modeling the effects of snow on climate to assessing avalanche risk. We directly imaged the microstructural changes in snow during temperature gradient metamorphism (TGM) under a constant gradient of 50 K m−1, using in situ time-lapse X-ray micro-tomography. This novel and non-destructive technique directly reveals the amount of ice that sublimates and is deposited during metamorphism, in addition to the exact locations of these phase changes. We calculated the average time that an ice volume stayed in place before it sublimated and found a characteristic residence time of 2–3 days. This means that most of the ice changes its phase from solid to vapor and back many times in a seasonal snowpack where similar temperature conditions can be found. Consistent with such a short timescale, we observed a mass turnover of up to 60% of the total ice mass per day. The concept of hand-to-hand transport for the water vapor flux describes the observed changes very well. However, we did not find evidence for a macroscopic vapor diffusion enhancement. The picture of {temperature gradient metamorphism} produced by directly observing the changing microstructure sheds light on the micro-physical processes and could help to improve models that predict the physical properties of snow.

Effect of somatostatin on circadian rhythms of firing and 2-deoxyglucose uptake in rat suprachiasmatic slices

1993 ◽  
Vol 265 (5) ◽  
pp. R1199-R1204 ◽  
Author(s):  
T. Hamada ◽  
S. Shibata ◽  
A. Tsuneyoshi ◽  
K. Tominaga ◽  
S. Watanabe
Keyword(s):  
Circadian Rhythm ◽  
Vasoactive Intestinal Polypeptide ◽  
Phase Changes ◽  
Circadian Clocks ◽  
Constant Darkness ◽  
Phase Resetting ◽  
Firing Activity ◽  
Light Pulses ◽  
Circadian Time

In mammals, the suprachiasmatic nucleus (SCN) of the hypothalamus appears to act as a circadian clock. The SCN vasoactive intestinal polypeptide-like immunoreactive neurons, which may act to mediate photic information in the SCN, receive input from neurons immunoreactive for somatostatin (SST). Therefore we investigated the role of SST as a transmitter for entrainment by analyzing the phase-resetting effect of SST on the circadian rhythm of SCN firing activity. Perfusion of SST increased 2-deoxyglucose uptake at circadian time (CT) 18, but not at CT6. A 1-h or 15-min treatment with SST produced phase delays when it was administered at CT13-14 and phase advances at CT22-23. Thus SST-induced phase changes are similar to those for light pulses to animals under constant darkness. The present findings suggest that SST is a transmitter for mediating information of entrainment to circadian clocks within the SCN.

scholarly journals Effects of 10-Week Concurrent Training on Insulin Resistance and the Serum Levels of Vaspin and Visfatin in Overweight Females

2019 ◽  
Vol 25 (3) ◽  
pp. 146-157
Author(s):  
Abdolreza Kazemi ◽  
◽  
Sareh Mahalati ◽  
Keyword(s):  
Insulin Resistance ◽  
Metabolic Diseases ◽  
Intervention Group ◽  
Serum Levels ◽  
Analysis Of Covariance ◽  
Concurrent Training ◽  
Improve Insulin Sensitivity ◽  
Glucose Levels ◽  
Kerman City ◽  
Training Protocol

Aims: The present study investigated the effects of a 10-week concurrent training on the serum levels of vaspin and visfatin in overweight females. Methods & Materials: Twenty-four over-weight females from Kerman City, Iran (Mean±SD age: 11.23±0.62 years; Mean±SD weight: 64.83±2.70kg; Mean±SD BMI: 27.97±0.47 kg/m2) were randomly assigned into the control and concurrent training groups. The intervention group performed the training protocol as follows: endurance training: 65-85% of Vo2 max for 20 minutes per session, and resistance training: 50-60% of One Repetition Maximum (1RM) for 30 minutes per session and 3 days a week for 10 weeks. Fasting plasma vaspin, visfatin, and insulin levels were measured by ELISA method. To analyze the data, Analysis of Covariance (ANCOVA) was used. Findings: Performing 10 weeks of concurrent training significantly decreased vaspin and visfatin plasma levels, and insulin resistance resting levels (P≤0.05); however, there was no significant decrease in glucose levels. Conclusion: Concurrent training can decrease insulin resistance, probably by reducing vaspin and visfatin in overweight females. Therefore, it is suggested that overweight females use concurrent training to improve insulin sensitivity and prevent metabolic diseases.

scholarly journals Chronic Corticosterone Disrupts the Circadian Rhythm of CRH Expression and M6a RNA Methylation in the Chicken Hypothalamus

2021 ◽  
Author(s):  
Yang Yang ◽  
Wanwan Han ◽  
Aijia Zhang ◽  
Mindie Zhao ◽  
Wei Cong ◽  
...  
Keyword(s):  
Circadian Rhythm ◽  
Circadian Rhythms ◽  
Chronic Stress ◽  
Hpa Axis ◽  
Clock Genes ◽  
Diurnal Fluctuation ◽  
Opposite Pattern ◽  
Rna Methylation ◽  
Diurnal Patterns ◽  
M6a Rna Methylation

Abstract Corticotropin-releasing hormone (CRH), the major secretagogue of the hypothalamic-pituitary-adrenal (HPA) axis, is intricately intertwined with the clock genes to regulate the circadian rhythm of various body functions. N6-methyladenosine (m6A) RNA methylation is involved in the regulation of circadian rhythm, yet it remains unknown whether CRH expression and m6A modification oscillate with the clock genes in chicken hypothalamus and how the circadian rhythms change under chronic stress. Here, we show that chronic exposure to corticosterone (CORT) eliminated the diurnal patterns of plasma CORT and melatonin levels in the chicken. The circadian rhythms of clock genes in hippocampus, hypothalamus and pituitary are all disturbed to different extent in CORT-treated chickens. The most striking changes occur in hypothalamus in which the diurnal fluctuation of CRH mRNA is flattened, together with mRNA of other feeding-related neuropeptides. Interestingly, hypothalamic m6A level oscillates in an opposite pattern to CRH mRNA, with lowest m6A level after midnight (ZT18) corresponding to the peak of CRH mRNA before dawn (ZT22). CORT diminished the circadian rhythm of m6A methylation with significantly increased level at night. Further site-specific m6A analysis on 3’UTR of CRH mRNA indicates that higher m6A on 3’UTR of CRH mRNA coincides with lower CRH mRNA at night (ZT18 and ZT22). Our results indicate that chronic stress disrupts the circadian rhythms of CRH expression in hypothalamus, leading to dysfunction of HPA axis in the chicken. RNA m6A modification is involved in the regulation of circadian rhythms in chicken hypothalamus under both basal and chronic stress conditions.

Sign in / Sign up

Export Citation Format

Share Document