scholarly journals 111 Artificial Light-Triggered Sleep Deprivation May Lead to Allodynia in Rodent Model

SLEEP ◽  
2021 ◽  
Vol 44 (Supplement_2) ◽  
pp. A45-A46
Author(s):  
Skyler Kanegi ◽  
Armen Akopian
Keyword(s):  
Sleep Deprivation ◽  
Light Exposure ◽  
Light Stimulus ◽  
Continuous Light ◽  
Artificial Light ◽  
Light Cycle ◽  
Tissue Samples ◽  
Mechanical Threshold ◽  
Dim Light ◽  
Von Frey Filaments

Abstract Introduction The combination of artificial light and lack of exposure to natural light can delay the circadian clock, dysregulate the circadian cycle, and decrease alertness upon waking. This effect has been especially significant during the COVID-19 pandemic, where overexposure to artificial light at improper hours has contributed to increased rates of clinical insomnia. Artificial light may also contribute to concomitant neurological conditions such as primary headache, but the mechanisms by which light triggers sleep deprivation-induced headache are not well-understood. Methods To measure pain sensitivity, we habituated 13 wild-type male mice to von Frey filaments applied to the periorbital area until there was no response to 0.6g stimulus. We then applied 5 lux of continuous dim light to mice during their usual 12-hour dark cycle. The 12-hour light cycle remained unchanged with 200 lux continuous light. Three groups of mice experienced the dim light stimulus for one, three, or five consecutive days. Ambulation and rest activity were measured using SOF-812 Activity Monitor machines. After the experiment concluded, we waited 24 hours and measured mechanical threshold using von Frey filaments at 1, 3, 5, 8, and every 3 days subsequently until mice no longer responded to 0.6g stimulus. Results Artificial light triggered changes in circadian behavior including increased number of rest periods during 12-hour dark (dim light) cycle and shortened sleep duration during 12-hour light cycle. Following the artificial light stimulus, there was a significant decrease in mechanical threshold (P<0.05), representing allodynia. The one-day group displayed one day of significant allodynia. The three-day group displayed three days of significant allodynia. The five-day group displayed five days of significant allodynia. Conclusion Artificial light may trigger circadian dysregulation, and the duration of artificial light exposure seemed to be directly correlated to the duration of allodynia up to one week after the stimulus was removed. We will repeat these experiments and analyze CNS and PNS tissue samples to understand the underlying physiological and biochemical bases of how artificial light triggers sleep deprivation-induced headache. This knowledge could increase our understanding of the pathophysiology and comorbidity of sleep deprivation and headache. Support (if any) Funding was received from the National Institute of Health (NS104200).

Human circadian pacemaker is sensitive to light throughout subjective day without evidence of transients

1997 ◽  
Vol 273 (5) ◽  
pp. R1800-R1809 ◽  
Author(s):  
Megan E. Jewett ◽  
David W. Rimmer ◽  
Jeanne F. Duffy ◽  
Elizabeth B. Klerman ◽  
Richard E. Kronauer ◽  
...  
Keyword(s):  
Steady State ◽  
Response Curve ◽  
Phase Response Curve ◽  
Light Exposure ◽  
Light Stimulus ◽  
Dead Zone ◽  
Bright Light ◽  
Temperature Minimum ◽  
Circadian Pacemaker ◽  
Dim Light

Fifty-six resetting trials were conducted across the subjective day in 43 young men using a three-cycle bright-light (∼10,000 lx) stimulus against a background of very dim light (10–15 lx). The phase-response curve (PRC) to these trials was assessed for the presence of a “dead zone” of photic insensitivity and was compared with another three-cycle PRC that had used a background of ∼150 lx. To assess possible transients after the light stimulus, the trials were divided into 43 steady-state trials, which occurred after several baseline days, and 13 consecutive trials, which occurred immediately after a previous resetting trial. We found that 1) bright light induces phase shifts throughout subjective day with no apparent dead zone; 2) there is no evidence of transients in constant routine assessments of the fitted temperature minimum 1–2 days after completion of the resetting stimulus; and 3) the timing of background room light modulates the resetting response to bright light. These data indicate that the human circadian pacemaker is sensitive to light at virtually all circadian phases, implying that the entire 24-h pattern of light exposure contributes to entrainment.

156 Evening Light-Induced Circadian Phase Shift in Preschool-Aged Children

SLEEP ◽  
2021 ◽  
Vol 44 (Supplement_2) ◽  
pp. A63-A64
Author(s):  
Lauren Hartstein ◽  
Lameese Akacem ◽  
Cecilia Diniz Behn ◽  
Shelby Stowe ◽  
Kenneth Wright ◽  
...  
Keyword(s):  
Phase Shift ◽  
Light Exposure ◽  
Light Stimulus ◽  
Phase Delay ◽  
Healthy Children ◽  
Dependent Manner ◽  
Circadian Phase ◽  
Light Intensities ◽  
Dim Light ◽  
Dose Dependent

Abstract Introduction In adults, exposure to light at night delays the timing of the circadian clock in a dose-dependent manner with intensity. Although children’s melatonin levels are highly suppressed by evening bright light, the sensitivity of young children’s circadian timing to evening light is unknown. This research aimed to establish an illuminance response curve for phase delay in preschool children as a result of exposure to varying light intensities in the hour before bedtime. Methods Healthy children (n=36, 3.0 – 4.9 years, 39% males), participated in a 10-day protocol. For 7 days, children followed a strict parent-selected sleep schedule. On Days 8-10, an in-home dim-light assessment was performed. On Day 8, dim light melatonin onset (DLMO) was measured through saliva samples collected in 20-30-min intervals throughout the evening until 1-h past habitual bedtime. On Day 9, children were exposed to a white light stimulus (semi-randomly assigned from 5lx to 5000lx) for 1-h before their habitual bedtime, and saliva was collected before, during, and after the exposure. On Day 10, children provided saliva samples in the evening for 2.5-h past bedtime for a final DLMO assessment. Phase angle of entrainment (habitual bedtime – DLMObaseline) and circadian phase delay (DLMOfinal – DLMObaseline) were computed. Results Final DLMO (Day 10) shifted between -8 and 123 minutes (M = 56.1 +/- 33.6 min; negative value = phase advance, positive value = phase delay) compared with DLMO at baseline (Day 8). Raw phase shift did not demonstrate a dose-dependent relationship with light intensity. Rather, we observed a robust phase delay across all intensities. Conclusion These data suggest preschoolers’ circadian clocks are immensely sensitive to a large range of light intensities, which may be mechanistically influenced by less mature ophthalmologic features (e.g. clearer lenses, larger pupils). With young children’s ever-growing use of light-emitting devices and evening exposure to artificial lighting, as well as the prevalence of behavioral sleep problems, these findings may inform recommendations for parents on the effects of evening light exposure on sleep timing in early childhood. Support (if any) This research was supported with funds from the Eunice Kennedy Shriver National Institute of Child Health & Human Development (R01-HD087707).

scholarly journals The Effect on Rat Thymocytes of the Simultaneous In Vivo Exposure to 50-Hz Electric and Magnetic Field and to Continuous Light

2004 ◽  
Vol 4 ◽  
pp. 91-99 ◽  
Author(s):  
Daniela Quaglino ◽  
Miriam Capri ◽  
Luigi Zecca ◽  
Claudio Franceschi ◽  
Ivonne P. Ronchetti
Keyword(s):  
Light Exposure ◽  
Low Frequency ◽  
Continuous Light ◽  
Light Cycle ◽  
Sprague Dawley ◽  
Dark Light ◽  
Sprague Dawley Rats ◽  
Electric And Magnetic Fields

Thymus plays an important role in the immune system and can be modulated by numerous environmental factors, including electromagnetic fields (EMF). The present study has been undertaken with the aim to investigate the role of long-term exposure to extremely low frequency electric and magnetic fields (ELF-EMF) on thymocytes of rats housed in a regular dark/light cycle or under continuous light. Male Sprague-Dawley rats, 2 months old, were exposed or sham exposed for 8 months to 50-Hz sinusoidal EMF at two levels of field strength (1 kV/m, 5 μT and 5 kV/m, 100 μT, respectively). Thymus from adult animals exhibits signs of gradual atrophy mainly due to collagen deposition and fat substitution. This physiological involution may be accelerated by continuous light exposure that induces a massive death of thymocytes. The concurrent exposure to continuous light and to ELF-EMF did not change significantly the rate of mitoses compared to sham-exposed rats, whereas the amount of cell death was significantly increased, also in comparison with animals exposed to EMF in a 12-h dark-light cycle. In conclusion, long-term exposure to ELF-EMF, in animals housed under continuous light, may reinforce the alterations due to a photic stress, suggesting that,in vivo, stress and ELF-EMF exposure can act in synergy determining a more rapid involution of the thymus and might be responsible for an increased susceptibility to the potentially hazardous effects of ELF-EMF.

Diurnal variation in the b-wave implicit time of the human electroretinogram

1998 ◽  
Vol 15 (1) ◽  
pp. 55-67 ◽  
Author(s):  
M.W. HANKINS ◽  
R.J.M. JONES ◽  
K.H. RUDDOCK
Keyword(s):  
Diurnal Variation ◽  
Dark Adaptation ◽  
Light Exposure ◽  
Continuous Light ◽  
Implicit Time ◽  
Diurnal Changes ◽  
Light Cycle ◽  
Short Term ◽  
Rod System ◽  
Adaptation State

Photopic electroretinograms (ERGs) elicited by light flashes were recorded for three normal human subjects who were exposed, throughout, to natural ambient light cycles over 24-h day–night periods. ERGs were recorded either with the adaptation state of the eyes maintained at the level set by the natural ambient lighting, or after 10 min dark adaptation. The amplitudes and implicit times of both the a- and b-wave components of the ERG were examined and of these, only the b-wave implicit time exhibited significant diurnal variation, such that the nighttime values were 20–40% greater than those recorded during daytime. Such diurnal variations were observed under both recording conditions and cannot, therefore, be attributed to diurnal changes in the adaptation state of the cone photoreceptors. ERGs were recorded at midday and midnight during 24-h exposure to the natural light cycle, but during the recording period, the short-term adaptation state of the eye was controlled by exposure to rod saturating background field, so that visual sensitivity was the same at both recording times. The b-wave implicit times recorded at midnight were, nonetheless, greater than those recorded at midday. This difference is not, therefore, determined by the short-term state of retinal adaptation, but reflects long-term light history. Measurements performed under 24-h continuous light exposure showed no variation in the b-wave implicit time, whereas some measurements made during extended dark adaptation provided limited evidence for implicit time changes. By controlling the wavelengths to which the eye was exposed during the daylight phase of the diurnal cycle, it was shown that the shifts in b-wave implicit time associated with the change from dark to light are triggered by the rod system, although they are most clearly observed in the cone-dominant responses to long-wavelength light. The results demonstrate a diurnal variation in the temporal responses of the post-photoreceptoral cone pathways of the human retina, which is triggered by activation of the rod photoreceptors.

Nature of the light stimulus producing Aschoff's intensity effect and anovulation

1984 ◽  
Vol 247 (2) ◽  
pp. R296-R301 ◽  
Author(s):  
J. S. Ferraro ◽  
C. E. McCormack
Keyword(s):  
Wheel Running ◽  
Light Exposure ◽  
Light Stimulus ◽  
Continuous Light ◽  
Albino Rats ◽  
Circadian Cycle ◽  
Intensity Effect ◽  
Running Activity ◽  
Wheel Running Activity ◽  
Feedback Circuits

Using feedback circuits, light exposure was linked to wheel-running activity in female albino rats. Because the photosensitive portions of the circadian cycle are known to coincide with wheel-running activity, the feedback circuits concentrated light on the photosensitive portions of the cycle. In this type of lighting, the free-running period of locomotor activity was directly proportional to the light intensity (i.e., the Aschoff effect), and at an intensity of 100 1x, cyclic ovulation caused. Both these effects, which were previously thought to result only from exposure to continuous light (LL), occurred even though these rats were exposed to only 4 h of light per circadian cycle. These results indicate that the consequences of LL are not due to the continuity of the light per se but represent the effects of light falling on discrete photosensitive portions of the circadian cycle.

scholarly journals Continuous Light Does Not Affect Atherosclerosis in APOE*3-Leiden.CETP Mice

2020 ◽  
Vol 35 (6) ◽  
pp. 598-611
Author(s):  
Maaike Schilperoort ◽  
Rosa van den Berg ◽  
Claudia P. Coomans ◽  
Padmini P. S. J. Khedoe ◽  
Ashna Ramkisoensing ◽  
...  
Keyword(s):  
Cardiovascular Disease ◽  
Disease Risk ◽  
Light Exposure ◽  
Continuous Light ◽  
Bright Light ◽  
Hdl Cholesterol ◽  
Constant Light ◽  
Artificial Light ◽  
Atherosclerotic Cardiovascular Disease ◽  
Cell Counts

Artificial light exposure is associated with dyslipidemia in humans, which is a major risk factor for the development of atherosclerotic cardiovascular disease. However, it remains unclear whether artificial light at night can exacerbate atherosclerosis. In this study, we exposed female APOE*3-Leiden.CETP mice, a well-established model for human-like lipid metabolism and atherosclerosis, to either a regular light-dark cycle or to constant bright light for 14 weeks. Mice exposed to constant light demonstrated a minor reduction in food intake, without any effect on body weight, body composition, or the weight of metabolic organs. Constant light increased the plasma levels of proatherogenic non–high-density lipoprotein (HDL) cholesterol but did not increase the size or severity of atherosclerotic lesions in the aortic root. Mice exposed to constant light did show lower immune cell counts, which could explain the absence of an effect of atherosclerosis despite increased non–HDL cholesterol levels. Behavioral analysis demonstrated variability in the response of mice to the light intervention. Constant light completely blunted behavioral rhythms in some mice, while others extended their behavioral period. However, rhythm strength was not an important determinant of atherosclerosis. Altogether, these results demonstrate that constant bright light does not affect atherosclerosis in APOE*3-Leiden.CETP mice. Whether artificial light exposure contributes to cardiovascular disease risk in humans remains to be investigated.

Effects of a two-hour early awakening and of bright light exposure on plasma patterns of cortisol, melatonin, prolactin and testosterone in man

1992 ◽  
Vol 126 (3) ◽  
pp. 201-205 ◽  
Author(s):  
Y Touitou ◽  
O Benoit ◽  
J Foret ◽  
A Aguirre ◽  
A Bogdan ◽  
...  
Keyword(s):  
Light Exposure ◽  
Light Stimulus ◽  
Bright Light ◽  
Male Students ◽  
Plasma Testosterone ◽  
Melatonin Concentration ◽  
Sleep Schedule ◽  
Dim Light ◽  
Bright Light Exposure ◽  
Neuroendocrine Functions

Bright light is a synchronizing agent that entrains human circadian rhythms and modifies various endocrine and neuroendocrine functions. The aim of the present study was to determine whether and how the exposure to a bright light stimulus during the 2 h following a 2 h earlier awakening could modify the disturbance induced by the the sleep deprivation on the plasma pattens of hormones whose secretion is sensitive to light and/or sleep, namely melatonin, prolactin, cortisol and testosterone. Six healthy and synchronized (lights on: 07.00–23.00) male students (22.5±1.1 years) with normal psychological profiles volunteered for the study in winter. The protocol consisted of a baseline control night (customary sleep schedule) followed by three shortened nights with a rising at 05.00 and a 2 h exposure to either dim light (50 lux; one week) or bright light (2000 lux: other week). Our study showed a phase advance of the circadian rhythm of plasma cortisol without significant modifications of the hormone mean or peak concentration. Plasma melatonin concentration decreased following bright light exposure, whereas no obvious modifications of plasma testosterone or prolactin patterns could be observed in this protocol.

The effects of intermittent light during the evening on sleepiness, sleep electroencephalographic spectral power and performance the next morning

2019 ◽  
Vol 51 (8) ◽  
pp. 1159-1177 ◽  
Author(s):  
MQ Yang ◽  
QW Chen ◽  
YY Zhu ◽  
Q Zhou ◽  
YG Geng ◽  
...  
Keyword(s):  
Cognitive Functioning ◽  
Light Exposure ◽  
Light Condition ◽  
Continuous Light ◽  
Bright Light ◽  
Beta Activity ◽  
Intermittent Light ◽  
Dim Light ◽  
And Performance ◽  
Electroencephalographic Activity

Most studies on the effects of light exposure have been conducted with continuous light. The present study investigated the effects of intermittent light exposure on sleepiness, mood, electroencephalographic activity during sleep and performance the next morning. Fifteen volunteers were scheduled to come to the sleep laboratory to experience different lighting conditions: intermittent bright light, continuous bright light and continuous dim light. Subjective sleepiness and mood were assessed during light exposure, with electroencephalographic recording during sleep. After waking the next morning, participants filled out questionnaires and went through two cognitive tasks. The results revealed significantly lower ratings of sleepiness after intermittent light exposure, which is not different from the ratings in the continuous bright light condition, and an increase in vitality during later part of the evening and more beta activity during the first 90 minutes of sleep in the intermittent light condition, in comparison with the continuous dim light condition. However, both intermittent and continuous bright light exposure showed no difference from the continuous dim light condition in subjects' mood and cognitive functioning the next morning. The data indicated intermittent light during evening decreased sleepiness, had only minimal impact on mood in the evening, increased beta electroencephalographic activity during sleep, but had no significant influence on cognitive functioning the next morning.

scholarly journals Antarctic krill (Euphausia superba) exhibit positive phototaxis to white LED light

Polar Biology ◽  
2021 ◽  
Vol 44 (3) ◽  
pp. 483-489
Author(s):  
Bjørn A. Krafft ◽  
Ludvig A. Krag
Keyword(s):  
Antarctic Krill ◽  
Light Exposure ◽  
Euphausia Superba ◽  
Marine Species ◽  
Artificial Light ◽  
White Led ◽  
Light Emitting ◽  
Positive Phototaxis ◽  
Led Light ◽  
Exposure Experiment

AbstractThe use of light-emitting diodes (LEDs) is increasingly used in fishing gears and its application is known to trigger negative or positive phototaxis (i.e., swimming away or toward the light source, respectively) for some marine species. However, our understanding of how artificial light influences behavior is poorly understood for many species and most studies can be characterized as trial and error experiments. In this study, we tested whether exposure to white LED light could initiate a phototactic response in Antarctic krill (Euphausia superba). Trawl-caught krill were used in a controlled artificial light exposure experiment conducted onboard a vessel in the Southern Ocean. The experiment was conducted in chambers with dark and light zones in which krill could move freely. Results showed that krill displayed a significant positive phototaxis. Understanding this behavioral response is relevant to development of krill fishing technology to improve scientific sampling gear, improve harvest efficiency, and reduce potential unwanted bycatch.

scholarly journals Critical Effects on Akt Signaling in Adult Zebrafish Brain Following Alterations in Light Exposure

Cells ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 637
Author(s):  
Nicholas S. Moore ◽  
Robert A. Mans ◽  
Mackenzee K. McCauley ◽  
Colton S. Allgood ◽  
Keri A. Barksdale
Keyword(s):  
Optic Tectum ◽  
Visual Processing ◽  
Environmental Enrichment ◽  
Glycogen Synthase ◽  
Light Exposure ◽  
Hsp70 Expression ◽  
Light Cycle ◽  
Adult Zebrafish ◽  
Sleep State ◽  
Zebrafish Brain

Evidence from human and animal studies indicate that disrupted light cycles leads to alterations of the sleep state, poor cognition, and the risk of developing neuroinflammatory and generalized health disorders. Zebrafish exhibit a diurnal circadian rhythm and are an increasingly popular model in studies of neurophysiology and neuropathophysiology. Here, we investigate the effect of alterations in light cycle on the adult zebrafish brain: we measured the effect of altered, unpredictable light exposure in adult zebrafish telencephalon, homologous to mammalian hippocampus, and the optic tectum, a significant visual processing center with extensive telencephalon connections. The expression of heat shock protein-70 (HSP70), an important cell stress mediator, was significantly decreased in optic tectum of adult zebrafish brain following four days of altered light exposure. Further, pSer473-Akt (protein kinase B) was significantly reduced in telencephalon following light cycle alteration, and pSer9-GSK3β (glycogen synthase kinase-3β) was significantly reduced in both the telencephalon and optic tectum of light-altered fish. Animals exposed to five minutes of environmental enrichment showed significant increase in pSer473Akt, which was significantly attenuated by four days of altered light exposure. These data show for the first time that unpredictable light exposure alters HSP70 expression and dysregulates Akt-GSK3β signaling in the adult zebrafish brain.

Sign in / Sign up

Export Citation Format

Share Document