scholarly journals The endogenous circadian system worsens asthma at night independent of sleep and other daily behavioral or environmental cycles

2021 ◽  
Vol 118 (37) ◽  
pp. e2018486118
Author(s):  
Frank A. J. L. Scheer ◽  
Michael F. Hilton ◽  
Heather L. Evoniuk ◽  
Sally A. Shiels ◽  
Atul Malhotra ◽  
...  
Keyword(s):  
Pulmonary Function ◽  
Circadian System ◽  
Behavioral Effects ◽  
Ambulatory Setting ◽  
Circadian Cycle ◽  
Adrenergic Agonist ◽  
Biological Time ◽  
The Common ◽  
Dim Light ◽  
Cycle Indices

Asthma often worsens at night. To determine if the endogenous circadian system contributes to the nocturnal worsening of asthma, independent of sleep and other behavioral and environmental day/night cycles, we studied patients with asthma (without steroid use) over 3 wk in an ambulatory setting (with combined circadian, environmental, and behavioral effects) and across the circadian cycle in two complementary laboratory protocols performed in dim light, which separated circadian from environmental and behavioral effects: 1) a 38-h “constant routine,” with continuous wakefulness, constant posture, 2-hourly isocaloric snacks, and 2) a 196-h “forced desynchrony” incorporating seven identical recurring 28-h sleep/wake cycles with all behaviors evenly scheduled across the circadian cycle. Indices of pulmonary function varied across the day in the ambulatory setting, and both laboratory protocols revealed significant circadian rhythms, with lowest function during the biological night, around 4:00 AM, uncovering a nocturnal exacerbation of asthma usually unnoticed or hidden by the presence of sleep. We also discovered a circadian rhythm in symptom-based rescue bronchodilator use (β2-adrenergic agonist inhaler) whereby inhaler use was four times more likely during the circadian night than day. There were additive influences on asthma from the circadian system plus sleep and other behavioral or environmental effects. Individuals with the lowest average pulmonary function tended to have the largest daily circadian variations and the largest behavioral cycle effects on asthma. When sleep was modeled to occur at night, the summed circadian, behavioral/environmental cycle effects almost perfectly matched the ambulatory data. Thus, the circadian system contributes to the common nocturnal worsening of asthma, implying that internal biological time should be considered for optimal therapy.

scholarly journals Separate and interacting effects of the endogenous circadian system and behaviors on plasma aldosterone in humans

2019 ◽  
Vol 316 (2) ◽  
pp. R157-R164 ◽  
Author(s):  
Saurabh S. Thosar ◽  
Jose F. Rueda ◽  
Alec M. Berman ◽  
Michael R. Lasarev ◽  
Maya X. Herzig ◽  
...  
Keyword(s):  
Circadian System ◽  
Plasma Aldosterone ◽  
Jet Lag ◽  
Circadian Cycle ◽  
Circadian Period ◽  
Nocturnal Sleep ◽  
Circadian Phase ◽  
Dim Light ◽  
And Behaviors ◽  
Healthy Participants

Measurements of aldosterone for diagnosis of primary aldosteronism are usually made from blood sampled in the morning when aldosterone typically peaks. We tested the relative contributions and interacting influences of the circadian system, ongoing behaviors, and prior sleep to this morning peak in aldosterone. To determine circadian rhythmicity and separate effects of behaviors on aldosterone, 16 healthy participants completed a 5-day protocol in dim light while all behaviors ranging from sleep to exercise were standardized and scheduled evenly across the 24-h circadian period. In another experiment, to test the separate effects of prior nocturnal sleep or the inactivity that accompanies sleep on aldosterone, 10 healthy participants were studied across 2 nights: 1 with sleep and 1 with maintained wakefulness (randomized order). Plasma aldosterone was measured repeatedly in each experiment. Aldosterone had a significant endogenous rhythm ( P < 0.001), rising across the circadian night and peaking in the morning (~8 AM). Activity, including exercise, increased aldosterone, and different behaviors modulated aldosterone differently across the circadian cycle (circadian phase × behavior interaction; P < 0.001). In the second experiment, prior nocturnal sleep and prior rested wakefulness both increased plasma aldosterone ( P < 0.001) in the morning, to the same extent as the change in circadian phases between evening and morning. The morning increase in aldosterone is due to effects of the circadian system plus increased morning activities and not prior sleep or the inactivity accompanying sleep. These findings have implications for the time of and behaviors preceding measurement of aldosterone, especially under conditions of shift work and jet lag.

The Importance of Light in Our Lives

2021 ◽  
pp. 239-256
Author(s):  
David Baeza Moyano ◽  
Roberto Alonso González Lezcano
Keyword(s):  
Visual System ◽  
Biological Function ◽  
Circadian System ◽  
New Findings ◽  
The Common ◽  
Indoor Lighting ◽  
Illuminance Uniformity

The light that enters through our eyes is not only for vision. The human circadian system responds to light differently than the visual system. The timing of each biological function in mammals is directed by the main clock located in the Supraquiasmic Nucleus, which is regulated by light. However, until now, only the interaction of light with our visual system has been taken into account when choosing the parameters of indoor lighting sources, including those in the classroom. In the publications about school lighting, the first concern was the common parameters of indoor lighting such as horizontal workplane illuminance, illuminance uniformity, and avoiding reflections on different surfaces. In this chapter, the authors show publications about new findings on the effects of light on people, studies carried out in different countries aimed at improving classroom lighting, current regulations on lighting related to classroom lighting, and new parameters that are being considered, along with those already used for new and better lighting.

Response of hamster circadian system to transitions between light and darkness

1986 ◽  
Vol 250 (4) ◽  
pp. R708-R711 ◽  
Author(s):  
H. E. Albers
Keyword(s):  
Activity Rhythm ◽  
Phase Shifts ◽  
Circadian System ◽  
Circadian Cycle ◽  
Circadian Activity ◽  
Syrian Hamsters ◽  
Circadian Activity Rhythm ◽  
Free Running ◽  
Activity Onset

The effects of exposure to sudden transitions from dark to light (DL) and light to dark (LD) were determined on the free-running circadian activity rhythm of Syrian hamsters. The activity rhythm was phase delayed by 1-2 h by DL transitions provided during the 12-h interval before activity onset (subjective day). In contrast, DL transitions produced phase advances of approximately 1 h 2-12 h after activity onset. LD transitions tended to produce phase advances throughout the circadian cycle. During the subjective day, LD transitions resulted in phase advances of up to 4 h. After the onset of activity, LD transitions produced phase advances of a lesser magnitude than during the subjective day. In addition, some phase delays were also observed. When the phase shifts produced by DL and LD transitions were combined additively these transitions could account for the phase shifts previously reported for brief pulses of light.

scholarly journals Effect of Long-Term Exposure to Constant Dim Light on the Circadian System of Rats

Neurosignals ◽  
2005 ◽  
Vol 14 (3) ◽  
pp. 117-125 ◽  
Author(s):  
Chiaki Fukuhara ◽  
Jacopo Aguzzi ◽  
Nicole Bullock ◽  
Gianluca Tosini
Keyword(s):  
Circadian System ◽  
Dim Light

scholarly journals Large variation among photoreceptors as the basis of visual flexibility in the common backswimmer

2014 ◽  
Vol 281 (1795) ◽  
pp. 20141177 ◽  
Author(s):  
Esa-Ville Immonen ◽  
Irina Ignatova ◽  
Anna Gislen ◽  
Eric Warrant ◽  
Mikko Vähäsöyrinki ◽  
...  
Keyword(s):  
Microscopic Analysis ◽  
Physiological Mechanisms ◽  
Absolute Sensitivity ◽  
Prey Animal ◽  
The Common ◽  
Dim Light ◽  
Retinal Structure ◽  
Open Rhabdom ◽  
Better Than ◽  
New Habitats

The common backswimmer, Notonecta glauca , uses vision by day and night for functions such as underwater prey animal capture and flight in search of new habitats. Although previous studies have identified some of the physiological mechanisms facilitating such flexibility in the animal's vision, neither the biophysics of Notonecta photoreceptors nor possible cellular adaptations are known. Here, we studied Notonecta photoreceptors using patch-clamp and intracellular recording methods. Photoreceptor size (approximated by capacitance) was positively correlated with absolute sensitivity and acceptance angles. Information rate measurements indicated that large and more sensitive photoreceptors performed better than small ones. Our results suggest that backswimmers are adapted for vision in both dim and well-illuminated environments by having open-rhabdom eyes with large intrinsic variation in absolute sensitivity among photoreceptors, exceeding those found in purely diurnal or nocturnal species. Both electrophysiology and microscopic analysis of retinal structure suggest two retinal subsystems: the largest peripheral photoreceptors provide vision in dim light and the smaller peripheral and central photoreceptors function primarily in sunlight, with light-dependent pigment screening further contributing to adaptation in this system by dynamically recruiting photoreceptors with varying sensitivity into the operational pool.

scholarly journals A Natural History Study of VCP Associated Vacuolar Myopathy in a Patient with the Common R155H Mutation

2020 ◽  
pp. 1-7
Author(s):  
Virginia Kimonis ◽  
David Sweetman ◽  
Jake Plewa ◽  
Minh Nguyen ◽  
Virginia Kimonis
Keyword(s):  
Natural History ◽  
Pulmonary Function ◽  
Inclusion Body ◽  
Rating Scale ◽  
Gene Mutations ◽  
Inherited Disease ◽  
History Data ◽  
Inclusion Body Myopathy ◽  
The Common

Background: IBMPFD (Inclusion Body Myopathy associated with Paget disease of the bone and Frontotemporal Dementia) is an autosomal dominant inherited disease caused by VCP gene mutations. Very little natural history data exists on this disease. We report a patient with a significant family history of IBMPFD associated with the common R155H mutation in the VCP gene. Objective: This study will address the lack of long-term data for muscle strength, and respiratory function in IBMPFD. The hypothesis is that detailed analysis in a single patient will provide meaningful natural history data in IBMPFD, a progressive neurodegenerative disease. Method: Regression analysis was performed across multiple parameters related to myopathy including dynamometry, MRC scale, IBM functional rating scale, pulmonary function studies and sleep quality. Results: Measurements of this patient highlight progressive generalized weakness in proximal and distal regions, decline in pulmonary function, and asymmetrical strength differences of the upper extremities. Measurements over five years revealed an overall deterioration with a slope of -1.13 and R2 value of 0.77. Conclusion: This unique data derived from long-term evaluations in a patient provides the first report of the rate of progression of muscle weakness and pulmonary function deterioration in VCP associated inclusion body myopathy.

Effect of ovariectomy and estradiol on unity of female rat circadian rhythms

1989 ◽  
Vol 257 (5) ◽  
pp. R1241-R1250 ◽  
Author(s):  
E. M. Thomas ◽  
S. M. Armstrong
Keyword(s):  
Circadian Rhythms ◽  
Circadian System ◽  
Illumination Level ◽  
Single Band ◽  
Ovariectomized Rats ◽  
Female Rat ◽  
Activity Rhythms ◽  
Running Activity ◽  
Free Running ◽  
Dim Light

Sixteen rats were ovariectomized and given either a 1-cm implant of crystalline estradiol-17 beta (eight rats) or an empty implant (eight rats). A further six rats were sham ovariectomized and given empty implants, and eight rats were left unoperated. The rats were exposed to 70 days of constant dim light (LL) with a maximum illumination level of 20 lx, and circadian running and drinking rhythms were monitored. In LL, both the running and drinking activity rhythms of the ovariectomized, blank-implanted rats became markedly disrupted, whereas unoperated and sham-operated rats maintained unified rhythms. Estradiol-implanted rats developed fewer rhythm desynchronies, and the majority displayed a single band of free-running activity. Rather than being arrhythmic, the activity of the LL-exposed ovariectomized rats appeared to contain several free-running components. Thus these data are consistent with the concept of a multioscillatory basis to the circadian system and support a role for the ovary and its hormone estradiol in the maintenance of coherence between component oscillators.

scholarly journals Enhanced Circadian Entrainment in Mice and Its Utility under Human Shiftwork Schedules

2019 ◽  
Vol 1 (3) ◽  
pp. 394-413
Author(s):  
Thijs J. Walbeek ◽  
Elizabeth M. Harrison ◽  
Robert R. Soler ◽  
Michael R. Gorman
Keyword(s):  
Circadian System ◽  
Day Length ◽  
Work Demands ◽  
Proof Of Concept ◽  
Light At Night ◽  
Experimental Conditions ◽  
Rapid Changes ◽  
Experimental Protocols ◽  
Flexible Adaptation ◽  
Dim Light

The circadian system is generally considered to be incapable of adjusting to rapid changes in sleep/work demands. In shiftworkers this leads to chronic circadian disruption and sleep loss, which together predict underperformance at work and negative health consequences. Two distinct experimental protocols have been proposed to increase circadian flexibility in rodents using dim light at night: rhythm bifurcation and T-cycle (i.e., day length) entrainment. Successful translation of such protocols to human shiftworkers could facilitate alignment of internal time with external demands. To assess entrainment flexibility following bifurcation and exposure to T-cycles, mice in Study 1 were repeatedly phase-shifted. Mice from experimental conditions rapidly phase-shifted their activity, while control mice showed expected transient misalignment. In Study 2 and 3, mice followed a several weeks-long intervention designed to model a modified DuPont or Continental shiftwork schedule, respectively. For both schedules, bifurcation and nocturnal dim lighting reduced circadian misalignment. Together, these studies demonstrate proof of concept that mammalian circadian systems can be rendered sufficiently flexible to adapt to multiple, rapidly changing shiftwork schedules. Flexible adaptation to exotic light-dark cycles likely relies on entrainment mechanisms that are distinct from traditional entrainment.

Insights into the activation mechanism of the visual receptor rhodopsin

2012 ◽  
Vol 40 (2) ◽  
pp. 389-393 ◽  
Author(s):  
Steven O. Smith
Keyword(s):  
Structural Biology ◽  
G Protein Coupled Receptors ◽  
Activation Mechanism ◽  
Class A ◽  
Highly Sensitive ◽  
The Common ◽  
Dim Light ◽  
And Function ◽  
G Protein Coupled ◽  
Visual Receptor

Recent advances in the structural biology of GPCRs (G-protein-coupled receptors) have provided insights into their structure and function. Comparisons of the visual and ligand-activated receptors highlight the unique elements of rhodopsin that allow it to function as a highly sensitive dim-light photoreceptor in vertebrates, as well as the common elements that it shares with the large class A GPCR family. However, despite progress, a number of questions remain unanswered about how these receptors are activated.

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