Search results for "circadian rhythms"
showing 10 items of 13 documents
How is the inner circadian clock controlled by interactive clock proteins?
2015
AbstractMost internationally travelled researchers will have encountered jetlag. If not, working odd hours makes most of us feel somehow dysfunctional. How can all this be linked to circadian rhythms and circadian clocks? In this review, we define circadian clocks, their composition and underlying molecular mechanisms. We describe and discuss recent crystal structures of Drosophila and mammalian core clock components and the enormous impact they had on the understanding of circadian clock mechanisms. Finally, we highlight the importance of circadian clocks for the daily regulation of human/mammalian physiology and show connections to overall fitness, health and disease.
Circadian and Infradian Activity Rhythms in the Mammalian Pineal Body
1982
The neuroendocrine nature of the pineal organ is well established. Linked to the optic system via postganglionic sympathetic fibres coming from the superior cervical ganglia, the parenchymal cells of the pineal synthesize serotonin from tryptophan and convert it to melatonin, the most widely studied pineal substance, and other indoleamines. Melatonin synthesis is stimulated by noradrenaline released from intrapineal sympathetic nerve fibres, involving β-adrenergic mechanisms and the adenyl cyclase-cAMP-system. The rate-limiting enzyme of melatonin formation is serotonin-N-acetyltransferase (NAT) that converts serotonin to N-acetylserotonin. Hydroxyindole-O-methyltransferase (HIOMT) catalyze…
Melatonin Levels in Children with Obesity Are Associated with Metabolic Risk and Inflammatory Parameters
2021
Melatonin, the hormone of circadian rhythm regulation, is involved in the modulation of mitochondrial activity through its antioxidant and anti-inflammatory properties. Alteration of circadian rhythms such as sleep is related to obesity and metabolic pathogenesis in adulthood, but studies during childhood are scarce. The present study investigated the association of melatonin with metabolic and inflammatory markers in children with (n = 113) and without obesity (n = 117). Melatonin was measured in saliva four and two hours before bedtime, and after one hour of sleep. Cardiometabolic factors, high sensitivity C-reactive protein, immune markers (monocyte chemoattractant protein-1, plasminogen…
Diurnal changes in the perception of emotions in music: Does the time of day matter?
2014
According to the Hindustani music tradition, the ability of a song to induce certain emotions depends on the time of day: playing a song at the right time is said to maximise its emotional effect. The present exploratory study investigated this claim by combining findings in chronobiology, mood research and music perception. It has already been established that some aspects of our mood fluctuations follow a cyclical pattern. Besides, it is a known fact that our current mood influences our perception and assessment of emotions. However, these elements have never been linked together in a study examining the effect of mood cyclicity on perceived emotions in music. To test the hypothesis of a…
Vector activity of Hyalesthes obsoletus living on nettles and transmitting a stolbur phytoplasma to grapevines: a case study
2007
International audience; We report a case study on the vector activity of a Hyalesthes obsoletus (Hemiptera: Cixiidae) population living on nettle plants (Urtica dioica) and transmitting a stolbur phytoplasma (Sp) to grapevines (Vitis vinifera). The research was conducted in a site that included a vineyard bordered with a large fallow area where nettles were the predominant plant species together with sparse old grapevines. Nettles hosted a high population of H. obsoletus. By using transparent sticky traps to sample adults, we observed that the daily flight activity of males and females to grapevines in the fallow was unimodal peaking between 15 and 21 h in the day. Adults were unable of gre…
EFFECTS OF SHIFT WORK ON CARDIOVASCULAR ACTIVITY, SERUM CORTISOL AND WHITE BLOOD CELLS COUNT IN A GROUP OF ITALIAN FISHERMEN
2012
We analyzed the effects of working activity and working shifts on the circadian rhythmicity and circadian phase relations of serum cortisol level, white blood cells count, resting heart rate and systolic/diastolic blood pressure in a group of italian fishermen. We observed a shift-induced displacement of cortisol secretion and a modification in leukocyte count. Moreover, systolic/diastolic blood pressure and resting heart rate were markedly influenced by the night shift, whereas no appreciable changes were observed after the morning and afternoon shifts, compared to pre-working values. These data suggest that the human circadian system is greatly influenced by shift work, and serum cortisol…
Estudio de la relación entre los hábitos de vida, las variaciones del ritmo circadiano y los trastornos metabólicos en la obesidad infantil
2022
Numerosos estudios realizados en trabajadores del turno de noche evidencian una relación entre la alteración de los ritmos circadianos y los trastornos metabólicos. En paralelo, otras investigaciones realizadas principalmente en modelos animales o en adultos humanos, muestran una relación entre los hábitos de vida, la duración insuficiente y la mala calidad del sueño, y el desarrollo de la obesidad y sus comorbilidades. Sin embargo, se sabe poco sobre el papel que desempeñan estos mecanismos en la actual epidemia de obesidad infantil. Por ello, desarrollamos un estudio de la relación entre los hábitos de vida, los ritmos circadianos de la melatonina y el metabolismo, en el contexto de la ob…
Different moment, different tune : how emotional perception of music changes with the time of day
2012
According to the classical music tradition of Northern India, the ability of a song to induce certain emotions depends on the time of day: playing a song at the right time is said to maximise its emotional effect. Transposing this idea into a Western context, I decided to investigate this claim by combining findings in chronobiology with findings in music and emotion. It has already been established that our mood fluctuations follow a cyclical pattern. Besides, it is a known fact that our current mood influences our ability to perceive emotions. However, no one has ever linked these elements together and studied diurnal mood variations and their effect on perceived emotions in music. To tes…
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…
Circadian rhythms in the pathogenesis of gastrointestinal diseases
2018
The etiology of digestive pathologies such as irritable bowel syndrome (IBS), inflammatory bowel diseases (IBD) and cancer is not yet fully understood. In recent years, several studies have evidenced circadian variations in mechanisms involved in digestive health. In situations of disturbed circadian rhythms (chronodisruption) where the central clock and the peripheral clocks receive incoherent signals, the synchronicity is lost producing implications for health. This lack of coordination could alter the tissue function and cause long term damage to the organs. Life habits such as sleep, physical exercise, social interaction, and feeding times are determinants for stability and integrity of…