Search results for "Circadian Rhythm"

Melatonin in Early Nutrition: Long-Term Effects on Cardiovascular System

2021

Breastfeeding protects against adverse cardiovascular outcomes in the long term. Melatonin is an active molecule that is present in the breast milk produced at night beginning in the first stages of lactation. This indoleamine appears to be a relevant contributor to the benefits of breast milk because it can affect infant health in several ways. The melatonin concentration in breast milk varies in a circadian pattern, making breast milk a chrononutrient. The consumption of melatonin can induce the first circadian stimulation in the infant’s body at an age when his/her own circadian machinery is not functioning yet. This molecule is also a powerful antioxidant with the ability to act on infa…

2021

Circadian clocks prepare the organism to cyclic environmental changes in light, temperature, or food availability. Here, we characterized the master clock in the brain of a strongly photoperiodic insect, the aphid Acyrthosiphon pisum, immunohistochemically with antibodies against A. pisum Period (PER), Drosophila melanogaster Cryptochrome (CRY1), and crab Pigment-Dispersing Hormone (PDH). The latter antibody detects all so far known PDHs and PDFs (Pigment-Dispersing Factors), which play a dominant role in the circadian system of many arthropods. We found that, under long days, PER and CRY are expressed in a rhythmic manner in three regions of the brain: the dorsal and lateral protocerebrum …

A Role of Histone Acetylation in the Regulation of Circadian Rhythm in Ants

2020

Summary In many organisms, circadian rhythms and associated oscillations in gene expression are controlled by post-translational modifications of histone proteins. Although epigenetic mechanisms influence key aspects of insect societies, their implication in regulating circadian rhythms has not been studied in social insects. Here we ask whether histone acetylation plays a role in adjusting circadian activity in the ant Temnothorax longispinosus. We characterized activity patterns in 20 colonies to reveal that these ants exhibit a diurnal rhythm in colony-level activity and can rapidly respond to changes in the light regime. Then we fed T. longispinosus colonies with C646, a chemical inhibi…

2017

The mammalian retina harbors a circadian clockwork that regulates vision and promotes healthiness of retinal neurons, mainly through directing the rhythmic release of the neurohormones dopamine-acting on dopamine D4 receptors-and melatonin-acting on MT1 and MT2 receptors. The gene Gnaz-a unique Gi/o subfamily member-was seen in the present study to be expressed in photoreceptors where its protein product Gαz shows a daily rhythm in its subcellular localization. Apart from subcellular localization, Gnaz displays a daily rhythm in expression-with peak values at night-in preparations of the whole retina, microdissected photoreceptors and photoreceptor-related pinealocytes. In retina, Gnaz rhyt…

Diagnostic and Therapeutic Approach to Sleep Disorders, High Blood Pressure and Cardiovascular Diseases. A Consensus Document by the Italian Society …

2021

Hypertension is a major contributor to fatal/nonfatal cardiovascular diseases, and timely identification and appropriate management of factors affecting hypertension and its control are mandatory public health issues. By inducing neurohormonal alterations and metabolic impairment, sleep disorders have an impact on a variety of cardiovascular risk factors, including hypertension, and ultimately increase the risk of cardiovascular events. There is evidence that qualitative and quantitative sleep disorders are associated with resistant hypertension and with impaired circadian blood pressure variations. However, sleep disturbances are often unrecognized, or heterogeneity exists in their managem…

Ocular Clocks: Adapting Mechanisms for Eye Functions and Health

2018

Vision is a highly rhythmic function adapted to the extensive changes in light intensity occurring over the 24-hour day. This adaptation relies on rhythms in cellular and molecular processes, which are orchestrated by a network of circadian clocks located within the retina and in the eye, synchronized to the day/night cycle and which, together, fine-tune detection and processing of light information over the 24-hour period and ensure retinal homeostasis. Systematic or high throughput studies revealed a series of genes rhythmically expressed in the retina, pointing at specific functions or pathways under circadian control. Conversely, knockout studies demonstrated that the circadian clock re…

zHSF1 modulates zper2 expression in zebrafish embryos

2018

International audience; HSF1 is a transcription factor that plays a key role in circadian resetting by temperature. We have used zebrafish embryos to decipher the roles of zHsf1, heat and light on zper2 transcription in vivo. Our results show that heat shock (HS) stimulated zper2 expression in the dark but has no cumulative effect combined with light. After light exposition, zper2 expression was 2.7 fold increased threefold in the hsf1-morphants in comparison to control embryos. Our results show that zHsf1 plays a positive role in HS-driven expression of zper2 in the dark but seems to act as an attenuator in the presence light.

Sleep, alertness and alertness management among commercial airline pilots on short-haul and long-haul flights

2016

Item does not contain fulltext Airline pilots' sleep and on-duty alertness are important focus areas in commercial aviation. Until now, studies pertaining to this topic have mainly focused on specific characteristics of flights and thus a comprehensive picture of the matter is not well established. In addition, research knowledge of what airline pilots actually do to maintain their alertness while being on duty is scarce. To address these gaps in research knowledge, we conducted a field study on a representative sample of the airline pilots of a medium-sized airline. The sample consisted of 90 pilots, of whom 30 flew long-haul (LH) routes, 30 short-haul (SH) routes, and 30 flew both. A tota…

2014

Objectives: Emerging evidence suggests that maternal obesity (MO) predisposes offspring to obesity and the recently described non-alcoholic fatty pancreas disease (NAFPD) but involved mechanisms remain unclear. Using a pathophysiologically relevant murine model, we here investigated a role for the biological clock--molecular core circadian genes (CCG) in the generation of NAFPD. Design: Female C57BL6 mice were fed an obesogenic diet (OD) or standard chow (SC) for 6 weeks, prior to pregnancy and throughout gestation and lactation: resulting offspring were subsequently weaned onto either OD (Ob_Ob and Con_Ob) or standard chow (Ob_Con and Con_Con) for 6 months. Biochemical, pro-inflammatory an…

Day/night serotonin levels in the pineal gland of male BALB/c mice with melatonin deficiency

1988

Abstract. Studies from another laboratory have shown that several strains of laboratory mice have a genetic defect for melatonin synthesis. In non-deficient species, melatonin synthesis undergoes a typical, β-adrenergically regulated day/night rhythm with low melatonin levels during daytime and high levels at night, the precursor serotonin showing an inverse behaviour. This study examines whether a day/night rhythm of pineal serotonin levels exists in melatonin-deficient male BALB/c mice. Mice kept under a lighting schedule of 12 h light (lights on at 07.00 h) and 12 h dark were killed at 13.00 and 01.00 h, respectively. Serotonin amounted to 12-15 ng/pineal and did not show regular day/nig…