| Records |
| Author |
Madahi, P.-G.; Ivan, O.; Adriana, B.; Diana, O.; Carolina, E. |
| Title |
Constant light during lactation programs circadian and metabolic systems |
Type  |
Journal Article |
| Year |
2018 |
Publication |
Chronobiology International |
Abbreviated Journal |
Chronobiol Int |
| Volume |
35 |
Issue |
8 |
Pages |
1153-1167 |
| Keywords |
Animals |
| Abstract |
Exposure to light at night is a disruptive condition for the adult circadian system, leading to arrhythmicity in nocturnal rodents. Circadian disruption is a risk factor for developing physiological and behavioral alterations, including weight gain and metabolic disease. During early stages of development, the circadian system undergoes a critical period of adjustment, and it is especially vulnerable to altered lighting conditions that may program its function, leading to long-term effects. We hypothesized that during lactation a disrupted light-dark cycle due to light at night may disrupt the circadian system and in the long term induce metabolic disorders. Here we explored in pups, short- and long-term effects of constant light (LL) during lactation. In the short term, LL caused a loss of rhythmicity and a reduction in the immunopositive cells of VIP, AVP, and PER1 in the suprachiasmatic nucleus (SCN). In the short term, the affection on the circadian clock in the pups resulted in body weight gain, loss of daily rhythms in general activity, plasma glucose and triglycerides (TG). Importantly, the DD conditions during development also induced altered daily rhythms in general activity and in the SCN. Exposure to LD conditions after lactation did not restore rhythmicity in the SCN, and the number of immunopositve cells to VIP, AVP, and PER1 remained reduced. In the long term, daily rhythmicity in general activity was restored; however, daily rhythms in glucose and TG remained disrupted, and daily mean levels of TG were significantly increased. Present results point out the programming role played by the LD cycle during early development in the function of the circadian system and on metabolism. This study points out the risk represented by exposure to an altered light-dark cycle during early stages of development. ABBREVIATIONS: AVP: arginine vasopressin peptide; CRY: cryptochrome; DD: constant darkness; DM: dorsomedial; LD: light-dark cycle; LL: constant light; NICUs: neonatal intensive care units; P: postnatal days; PER: period; S.E.M.: standard error of the mean; SCN: suprachiasmatic nucleus; TG: triglycerides; VIP: vasointestinal peptide; VL: ventrolateral; ZT: zeitgeber time. |
| Address |
a Facultad de Medicina , Universidad Nacional Autonoma de Mexico, UNAM , Mexico City , Mexico |
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English |
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| ISSN |
0742-0528 |
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| Notes |
PMID:29688088 |
Approved |
no |
| Call Number |
GFZ @ kyba @ |
Serial |
1884 |
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| Author |
Rahman, S.A.; St Hilaire, M.A.; Gronfier, C.; Chang, A.-M.; Santhi, N.; Czeisler, C.A.; Klerman, E.B.; Lockley, S.W. |
| Title |
Functional decoupling of melatonin suppression and circadian phase resetting in humans |
Type |
Journal Article |
| Year |
2018 |
Publication |
The Journal of Physiology |
Abbreviated Journal |
J Physiol |
| Volume |
596 |
Issue |
11 |
Pages |
2147-2157 |
| Keywords |
Human Health |
| Abstract |
KEY POINTS: There is assumed to be a monotonic association between melatonin suppression and circadian phase resetting induced by light exposure. We tested the association between melatonin suppression and phase resetting in humans. Sixteen young healthy participants received nocturnal bright light ( approximately 9500 lux) exposure of continuous or intermittent patterns, and different durations ranging from 12 min to 6.5 h. Intermittent exposure patterns showed significant phase shifts with disproportionately less melatonin suppression. Each and every bright light stimulus in an intermittent exposure pattern induced a similar degree of melatonin suppression, but did not appear to cause an equal magnitude of phase shift. These results suggest that phase shifts and melatonin suppression are functionally independent such that one cannot be used as a proxy measure of the other. ABSTRACT: Continuous experimental light exposures show that, in general, the conditions that produce greater melatonin suppression also produce greater phase shift, leading to the assumption that one can be used as a proxy for the other. We tested this association in 16 healthy individuals who participated in a 9-day inpatient protocol by assessing melatonin suppression and phase resetting in response to a nocturnal light exposure (LE) of different patterns: (i) dim-light control (<3 lux; n = 6) or (ii) two 12-min intermittent bright light pulses (IBL) separated by 36 min of darkness ( approximately 9500 lux; n = 10). We compared these results with historical data from additional LE patterns: (i) dim-light control (<3 lux; n = 11); (ii) single continuous bright light exposure of 12 min (n = 9), 1.0 h (n = 10) or 6.5 h (n = 6); or (iii) an IBL light pattern consisting of six 15-min pulses with 1.0 h dim-light recovery intervals between them during a total of 6.5 h (n = 7). All light exposure groups had significantly greater phase-delay shifts than the dim-light control condition (P < 0.0001). While a monotonic association between melatonin suppression and circadian phase shift was observed, intermittent exposure patterns showed significant phase shifts with disproportionately less melatonin suppression. Each and every IBL stimulus induced a similar degree of melatonin suppression, but did not appear to cause an equal magnitude of phase shift. These results suggest unique specificities in how light-induced phase shifts and melatonin suppression are mediated such that one cannot be used as a proxy measure of the other. |
| Address |
Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA |
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English |
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0022-3751 |
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| Notes |
PMID:29707782 |
Approved |
no |
| Call Number |
GFZ @ kyba @ |
Serial |
1887 |
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| Author |
Dimovski, A.M.; Robert, K.A. |
| Title |
Artificial light pollution: Shifting spectral wavelengths to mitigate physiological and health consequences in a nocturnal marsupial mammal |
Type |
Journal Article |
| Year |
2018 |
Publication |
Journal of Experimental Zoology. Part A, Ecological and Integrative Physiology |
Abbreviated Journal |
J Exp Zool A Ecol Integr Physiol |
| Volume |
329 |
Issue |
8-9 |
Pages |
497-505 |
| Keywords |
Animals; Lighting |
| Abstract |
The focus of sustainable lighting tends to be on reduced CO2 emissions and cost savings, but not on the wider environmental effects. Ironically, the introduction of energy-efficient lighting, such as light emitting diodes (LEDs), may be having a great impact on the health of wildlife. These white LEDs are generated with a high content of short-wavelength 'blue' light. While light of any kind can suppress melatonin and the physiological processes it regulates, these short wavelengths are potent suppressors of melatonin. Here, we manipulated the spectral composition of LED lights and tested their capacity to mitigate the physiological and health consequences associated with their use. We experimentally investigated the impact of white LEDs (peak wavelength 448 nm; mean irradiance 2.87 W/m(2) ), long-wavelength shifted amber LEDs (peak wavelength 605 nm; mean irradiance 2.00 W/m(2) ), and no lighting (irradiance from sky glow < 0.37 x 10(-3) W/m(2) ), on melatonin production, lipid peroxidation, and circulating antioxidant capacity in the tammar wallaby (Macropus eugenii). Night-time melatonin and oxidative status were determined at baseline and again following 10 weeks exposure to light treatments. White LED exposed wallabies had significantly suppressed nocturnal melatonin compared to no light and amber LED exposed wallabies, while there was no difference in lipid peroxidation. Antioxidant capacity declined from baseline to week 10 under all treatments. These results provide further evidence that short-wavelength light at night is a potent suppressor of nocturnal melatonin. Importantly, we also illustrate that shifting the spectral output to longer wavelengths could mitigate these negative physiological impacts. |
| Address |
Department of Ecology, Environment and Evolution, La Trobe University, Melbourne, Australia |
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English |
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2471-5638 |
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| Notes |
PMID:29722167 |
Approved |
no |
| Call Number |
GFZ @ kyba @ |
Serial |
1888 |
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| Author |
McLay, L.K.; Nagarajan-Radha, V.; Green, M.P.; Jones, T.M. |
| Title |
Dim artificial light at night affects mating, reproductive output, and reactive oxygen species in Drosophila melanogaster |
Type |
Journal Article |
| Year |
2018 |
Publication |
Journal of Experimental Zoology. Part A, Ecological and Integrative Physiology |
Abbreviated Journal |
J Exp Zool A Ecol Integr Physiol |
| Volume |
329 |
Issue |
8-9 |
Pages |
419-428 |
| Keywords |
Animals |
| Abstract |
Humans are lighting the night-time environment with ever increasing extent and intensity, resulting in a variety of negative ecological effects in individuals and populations. Effects of light at night on reproductive fitness traits are demonstrated across taxa however, the mechanisms underlying these effects are largely untested. One possible mechanism is that light at night may result in perturbed reactive oxygen species (ROS) and oxidative stress levels. Here, we reared Drosophila melanogaster under either dim (10 lx) light or no light (0 lx) at night for three generations and then compared mating and lifetime oviposition patterns. In a second experiment, we explored whether exposure to light at night treatments resulted in variation in ROS levels in the heads and ovaries of six, 23- and 36-day-old females. We demonstrate that dim light at night affects mating and reproductive output: 10 lx flies courted for longer prior to mating, and female oviposition patterns differed to 0 lx females. ROS levels were lower in the ovaries but not heads, of 10 lx compared with 0 lx females. We suggest that reduced ROS levels may reflect changes in ovarian physiology and cell signaling, which may be related to the differences observed in oviposition patterns. Taken together, our results indicate negative consequences for invertebrates under more stressful, urban, lit conditions and further investigation into the mechanisms driving these changes is warranted to manage invertebrate communities in a brighter future. |
| Address |
School of BioSciences, Faculty of Science, The University of Melbourne, Melbourne, Victoria, Australia |
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English |
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2471-5638 |
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| Notes |
PMID:29733537 |
Approved |
no |
| Call Number |
GFZ @ kyba @ |
Serial |
1889 |
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| Author |
Guetté, A.; Godet, L.; Juigner, M.; Robin, M. |
| Title |
Worldwide increase in Artificial Light At Night around protected areas and within biodiversity hotspots |
Type |
Journal Article |
| Year |
2018 |
Publication |
Biological Conservation |
Abbreviated Journal |
Biological Conservation |
| Volume |
223 |
Issue |
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Pages |
97-103 |
| Keywords |
Remote Sensing; Ecology; Conservation |
| Abstract |
Artificial Light At Night (ALAN) has several adverse impacts on biodiversity, and it has been recently used as a proxy to monitor human encroachment on landscapes at large spatial scales. The extent to which ALAN affects protected areas (PAs) and biodiversity hotspots (BHs) remains however untested at large spatial scales. We used this proxy to assess the spatial and temporal trends in the anthropization at a global scale within and around PAs and BHs. We found that ALAN is low and stable over time within PAs, but is the highest in a first outer belt (<25 km) around PAs, and tends to increase in a second outer belt (25–75 km). In the meantime, ALAN is higher within BHs than outside, and is even the highest and increasing over time in an inner belt, close to their periphery. Our results suggest that although PAs are creating safety zones in terms of ALAN, they tend to be more and more isolated from each other by a concentric human encroachment. In contrast, BHs are submitted to an increasing human pressure, especially in their inner periphery. Overall, we suggest integrating ALAN in large-scale conservation policies. |
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0006-3207 |
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Approved |
no |
| Call Number |
GFZ @ kyba @ |
Serial |
1890 |
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