Read by QxMD icon Read

Circadian activity

Sherie Ma, Craig M Smith, Anna Blasiak, Andrew L Gundlach
Relaxin-3 is a member of a superfamily of structurally-related peptides that includes relaxin and insulin-like peptide hormones. Soon after the discovery of the relaxin-3 gene, relaxin-3 was identified as an abundant neuropeptide in brain with a distinctive topographical distribution within a small number of GABA neuron populations that is well conserved across species. Relaxin-3 is thought to exert its biological actions through a single class-A GPCR - relaxin-family peptide receptor 3 (RXFP3). Class-A comprises GPCRs for relaxin-3 and insulin-like peptide-5 and other peptides such as orexin and the monoamine transmitters...
October 23, 2016: British Journal of Pharmacology
Clara Bien Peek, Daniel C Levine, Jonathan Cedernaes, Akihiko Taguchi, Yumiko Kobayashi, Stacy J Tsai, Nicolle A Bonar, Maureen R McNulty, Kathryn Moynihan Ramsey, Joseph Bass
Circadian clocks are encoded by a transcription-translation feedback loop that aligns energetic processes with the solar cycle. We show that genetic disruption of the clock activator BMAL1 in skeletal myotubes and fibroblasts increased levels of the hypoxia-inducible factor 1α (HIF1α) under hypoxic conditions. Bmal1(-/-) myotubes displayed reduced anaerobic glycolysis, mitochondrial respiration with glycolytic fuel, and transcription of HIF1α targets Phd3, Vegfa, Mct4, Pk-m, and Ldha, whereas abrogation of the clock repressors CRY1/2 stabilized HIF1α in response to hypoxia...
October 19, 2016: Cell Metabolism
Yaarit Adamovich, Benjamin Ladeuix, Marina Golik, Maarten P Koeners, Gad Asher
The mammalian circadian system consists of a master clock in the brain that synchronizes subsidiary oscillators in peripheral tissues. The master clock maintains phase coherence in peripheral cells through systemic cues such as feeding-fasting and temperature cycles. Here, we examined the role of oxygen as a resetting cue for circadian clocks. We continuously measured oxygen levels in living animals and detected daily rhythms in tissue oxygenation. Oxygen cycles, within the physiological range, were sufficient to synchronize cellular clocks in a HIF1α-dependent manner...
October 19, 2016: Cell Metabolism
Cinthia D Coria-Lucero, Rebeca S Golini, Ivana T Ponce, Nicolas Deyurka, Ana C Anzulovich, Silvia M Delgado, Lorena S Navigatore-Fonzo
Aging brain undergoes several changes leading to a decline in cognitive functions. Memory and learning-related genes such as Creb, Bdnf and its receptor TrkB, are expressed in different brain regions including prefrontal cortex. Those genes' proteins regulate a wide range of functions such as synaptic plasticity and long-term potentiation. In this work, our objectives were: 1) to investigate whether Creb1, Bdnf and TrkB genes display endogenous circadian expression rhythms, in the prefrontal cortex of rats maintained under constant darkness conditions; 2) to study the synchronization of those temporal patterns to the local cellular clock and 3) to evaluate the aging consequences on both cognition-related genes and activating clock transcription factor, BMAL1, rhythms...
October 19, 2016: Brain Research
Andreas Arendt, El-Sayed Baz, Monika Stengl
The circadian pacemaker of the Madeira cockroach Rhyparobia (Leucophaea) maderae is located in the accessory medulla (AME). Ipsi- and contralateral histaminergic compound eyes are required for photic entrainment. Light pulses delayed locomotor activity rhythms during the early night and advanced during the late night. Thus, different neuronal pathways might relay either light-dependent delays or advances to the clock. Injections of neuroactive substances combined with running-wheel assays suggested that GABA, PDF, myoinhibitory peptides (MIPs), and orcokinins (ORCs) are part of both entrainment pathways, while allatotropin (AT) only delayed locomotor rhythms at the early night...
October 20, 2016: Journal of Comparative Neurology
Gregory D M Potter, Debra J Skene, Josephine Arendt, Janet E Cade, Peter J Grant, Laura J Hardie
Circadian (∼ 24 hour) timing systems pervade all kingdoms of life, and temporally optimize behaviour and physiology in humans. Relatively recent changes to our environments, such as the introduction of artificial lighting, can disorganize the circadian system, from the level of the molecular clocks that regulate the timing of cellular activities to the level of synchronization between our daily cycles of behaviour and the solar day. Sleep/wake cycles are intertwined with the circadian system, and global trends indicate that these too are increasingly subject to disruption...
October 20, 2016: Endocrine Reviews
Rüdiger Hardeland
Dynamic aspects of melatonin's actions merit increasing future attention. This concerns particularly entirely different effects in senescent, weakened oscillators and in dysregulated oscillators of cancer cells that may be epigenetically blocked. This is especially obvious in the case of sirtuin 1 (SIRT1) which is upregulated by melatonin in aged tissues, but strongly downregulated in several cancer cells. These findings are not at all controversial, but are explained on the basis of divergent changes in weakened and dysregulated oscillators...
October 20, 2016: Journal of Pineal Research
Dirk Jan Stenvers, Rick van Dorp, Ewout Foppen, Jorge Mendoza, Anne-Loes Opperhuizen, Eric Fliers, Peter H Bisschop, Johanna H Meijer, Andries Kalsbeek, Tom Deboer
Exposure to light at night (LAN) is associated with insomnia in humans. Light provides the main input to the master clock in the hypothalamic suprachiasmatic nucleus (SCN) that coordinates the sleep-wake cycle. We aimed to develop a rodent model for the effects of LAN on sleep. Therefore, we exposed male Wistar rats to either a 12 h light (150-200lux):12 h dark (LD) schedule or a 12 h light (150-200 lux):12 h dim white light (5 lux) (LDim) schedule. LDim acutely decreased the amplitude of daily rhythms of REM and NREM sleep, with a further decrease over the following days...
October 20, 2016: Scientific Reports
Joseph F O'Grady, Laura S Hoelters, Martin T Swain, David C Wilcockson
BACKGROUND: Talitrus saltator is an amphipod crustacean that inhabits the supralittoral zone on sandy beaches in the Northeast Atlantic and Mediterranean. T. saltator exhibits endogenous locomotor activity rhythms and time-compensated sun and moon orientation, both of which necessitate at least one chronometric mechanism. Whilst their behaviour is well studied, currently there are no descriptions of the underlying molecular components of a biological clock in this animal, and very few in other crustacean species...
2016: PeerJ
Aurore Woller, Hélène Duez, Bart Staels, Marc Lefranc
To maintain energy homeostasis despite variable energy supply and consumption along the diurnal cycle, the liver relies on a circadian clock synchronized to food timing. Perturbed feeding and fasting cycles have been associated with clock disruption and metabolic diseases; however, the mechanisms are unclear. To address this question, we have constructed a mathematical model of the mammalian circadian clock, incorporating the metabolic sensors SIRT1 and AMPK. The clock response to various temporal patterns of AMPK activation was simulated numerically, mimicking the effects of a normal diet, fasting, and a high-fat diet...
October 18, 2016: Cell Reports
Alberto Ugolini, Laura S Hoelters, Alice Ciofini, Vittorio Pasquali, David C Wilcockson
Animals that use astronomical cues to orientate must make continuous adjustment to account for temporal changes in azimuth caused by Earth's rotation. For example, the Monarch butterfly possesses a time-compensated sun compass dependent upon a circadian clock in the antennae. The amphipod Talitrus saltator possesses both a sun compass and a moon compass. We reasoned that the time-compensated compass mechanism that enables solar orientation of T. saltator is located in the antennae, as is the case for Monarch butterflies...
October 19, 2016: Scientific Reports
Oscar Prospéro-García, Octavio Amancio-Belmont, Alline L Becerril Meléndez, Alejandra E Ruiz-Contreras, Mónica Méndez-Díaz
Sleep is regulated by several brain structures, neurotransmitters and neuromodulators. Endocannabinoids (eCBs) are a group of lipids with modulatory activity in the brain and bind mainly to cannabinoid receptors CB1R and CB2R, thereby modulating several brain functions, (memory, mood, food intake, pain perception). Oleoylethanolamide and palmitoylethanolamide belong to the N-acylethanolamides (NAEs) family, another type of active endogenous lipids. They bind to the peroxisome proliferator-activated receptor α but not to CB1R, thereby modulating food satiety, inflammation and pain...
October 15, 2016: Neuroscience and Biobehavioral Reviews
Eunjoo Cho, Euna Lee, Eun Young Kim
The circadian clock system enables organisms to anticipate the rhythmic environmental changes and to manifest behavior and physiology at advantageous times of day. Transcriptional/translational feedback loop (TTFL) is the basic feature of eukaryotic circadian clock and is based on the rhythmic association of circadian transcriptional activator and repressor. In Drosophila, repression of dCLOCK/CYCLE (dCLK/CYC) mediated transcription by PERIOD (PER) is critical for inducing circadian rhythms of gene expression...
October 19, 2016: BMB Reports
Kyoung Im Cho, Eun A Cho, Jung Ho Heo, Hyun Su Kim, Sung Il Im, Tae Joon Cha
OBJECTIVE: Increased sympathetic activity is one of the proposed mechanisms underlying exaggerated blood pressure (BP) response to exercise (EBPR). Heart rate recovery (HRR) is a simple non-invasive measurement analyzing autonomic nervous dysfunction, and has been shown to predict cardiovascular disease mortality. We aimed to the association between HRR and EBPR in patients with hypertension according to the circadian pattern and white coat hypertension. DESIGN AND METHOD: A total of 409 consecutive patients who simultaneously underwent Treadmill test and 24-hours ambulatory BP monitoring (ABPM) were included to this cross-sectional case-control study...
September 2016: Journal of Hypertension
Huan Wang, Hui Chen
OBJECTIVE: Circadian rhythm disruption is shown to be the cause of various health disorders. CLOCK and BMAL1, two core circadian transcription factors, were associated with the regulation of glucose homeostasis. This study evaluated the association between single nucleotide polymorphisms in CLOCK and BMAL1 gene and insulin resistance (IR) in hypertensive patients. DESIGN AND METHOD: We collected 334 outpatients with essential hypertension (EH), who have not taken any antihypertensive agents or stopped the medications for at least a week for this case-control study...
September 2016: Journal of Hypertension
Ayako Uchinaka, Yuri Kawashima, Yuki Sano, Mamoru Yoneda, Shogo Ito, Yusuke Sano, Kai Nagasawa, Natsumi Matsuura, Yuichiro Yamada, Toyoaki Murohara, Kohzo Nagata
OBJECTIVE: The pineal hormone melatonin, which regulates the body's circadian rhythm, possesses anti-oxidative and anti-inflammatory effects and thereby improves metabolic disorders. Ramelteon is a potent and highly selective agonist of melatonin receptors and attenuates age-associated hypertension and body weight gain in spontaneously hypertensive rats. However, the effects of ramelteon on cardiovascular and metabolic disorders in metabolic syndrome (MetS) remain unclear. We investigated the effects of ramelteon on cardiac and adipose tissue pathology in a rat model of MetS...
September 2016: Journal of Hypertension
Stefano Schiaffino, Bert Blaauw, Kenneth A Dyar
The circadian oscillations of muscle genes are controlled either directly by the intrinsic muscle clock or by extrinsic factors, such as feeding, hormonal signals, or neural influences, which are in turn regulated by the central pacemaker, the suprachiasmatic nucleus of the hypothalamus. A unique feature of circadian rhythms in skeletal muscle is motor neuron-dependent contractile activity, which can affect the oscillation of a number of muscle genes independently of the muscle clock. The role of the intrinsic muscle clock has been investigated using different Bmal1 knockout (KO) models...
2016: Skeletal Muscle
Henrik Oster, Etienne Challet, Volker Ott, Emanuela Arvat, E Ronald de Kloet, Derk-Jan Dijk, Stafford Lightman, Alexandros Vgontzas, Eve Van Cauter
Adrenal glucocorticoids are major modulators of multiple functions, including energy metabolism, stress responses, immunity, and cognition. The endogenous secretion of glucocorticoids is normally characterized by a prominent and robust circadian (around 24 hours) oscillation, with a daily peak around the time of the habitual sleep-wake transition and minimal levels in the evening and early part of the night. It has been long recognized that this 24-h rhythm partly reflects the activity of a master circadian pacemaker located in the suprachiasmatic nucleus of the hypothalamus...
October 17, 2016: Endocrine Reviews
Jennifer Gile, Tobias Eckle
Cardiovascular disease is the number one cause of death worldwide. A powerful strategy for cardioprotection would be to identify specific molecules or targets that mimic ischemic preconditioning (IP), where short non-lethal episodes of ischemia and reperfusion prior to myocardial infarction result in dramatic reduction of infarct sizes. Since 1960 researchers believed that adenosine has a strong cardio-protective potential. In fact, with the discovery of cardiac IP in 1986 by Murry et al., adenosine was the first identified molecule that was used in studying the underlying mechanism of IP...
2016: Journal of Nature and Science
Naoya Matsunaga, Eriko Ikeda, Keisuke Kakimoto, Miyako Watanabe, Naoya Shindo, Akito Tsuruta, Hisako Ikeyama, Kengo Hamamura, Kazuhiro Higashi, Tomohiro Yamashita, Hideaki Kondo, Yuya Yoshida, Masaki Matsuda, Takashi Ogino, Kazutaka Tokushige, Kazufumi Itcho, Yoko Furuichi, Takaharu Nakao, Kaori Yasuda, Atsushi Doi, Toshiaki Amamoto, Hironori Aramaki, Makoto Tsuda, Kazuhide Inoue, Akio Ojida, Satoru Koyanagi, Shigehiro Ohdo
Chronic kidney disease (CKD) is a global health problem, and novel therapies to treat CKD are urgently needed. Here, we show that inhibition of G0/G1 switch 2 (G0s2) ameliorates renal inflammation in a mouse model of CKD. Renal expression of chemokine (C-C motif) ligand 2 (Ccl2) was increased in response to p65 activation in the kidneys of wild-type 5/6 nephrectomy (5/6Nx) mice. Moreover, 5/6Nx Clk/Clk mice, which carry homozygous mutations in the gene encoding circadian locomotor output cycles kaput (CLOCK), did not exhibit aggravation of apoptosis or induction of F4/80-positive cells...
October 6, 2016: EBioMedicine
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"