Influence of photoperiod on hormones, behavior, and immune function

Walton, James C.; Weil, Zachary M.; Nelson, Randy J.

doi:10.1016/j.yfrne.2010.12.003

Cited by 173 publications

(142 citation statements)

References 341 publications

(410 reference statements)

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“…S easonal changes in the photoperiod of the Earth's temperate zones affect the behavior and physiology of many organisms (1). The central circadian clock, located in the suprachiasmatic nucleus (SCN) of the anterior hypothalamus, can adapt to changes in day length and displays a compressed circadian pattern of electrical activity in short winter days and a decompressed pattern in long summer days (2).…”

mentioning

confidence: 99%

Seasonal induction of GABAergic excitation in the central mammalian clock

Farajnia

Westering

Meijer

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

107

129

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The balance between excitation and inhibition is essential for the proper function of neuronal networks in the brain. The inhibitory neurotransmitter γ-aminobutyric acid (GABA) contributes to the network dynamics within the suprachiasmatic nucleus (SCN), which is involved in seasonal encoding. We investigated GABAergic activity and observed mainly inhibitory action in SCN neurons of mice exposed to a short-day photoperiod. Remarkably, the GABAergic activity in a long-day photoperiod shifts from inhibition toward excitation. The mechanistic basis for this appears to be a change in the equilibrium potential of GABA-evoked current. These results emphasize that environmental conditions can have substantial effects on the function of a key neurotransmitter in the central nervous system.S easonal changes in the photoperiod of the Earth's temperate zones affect the behavior and physiology of many organisms (1). The central circadian clock, located in the suprachiasmatic nucleus (SCN) of the anterior hypothalamus, can adapt to changes in day length and displays a compressed circadian pattern of electrical activity in short winter days and a decompressed pattern in long summer days (2). This pattern is based on a change in the phase distribution of the activity patterns of individual neurons, which becomes broad in the summer and narrow in the winter (3). The mechanisms that mediate and regulate photoperiod-induced phase distributions are currently not known.The neurotransmitter γ-aminobutyric acid (GABA) is believed to be involved in the phase adjustment and synchronization of the SCN neuronal network (4, 5). GABA and its receptors are expressed in most SCN neurons (6). GABAergic inhibition has been indicated to be important in normal physiological function within the brain. Alterations in this system (i.e., less inhibition) are shown to cause neurological disorders, such as epilepsy and autism (7,8). In addition to its classical inhibitory function within the SCN network, GABA has more recently been shown to also act as an excitatory transmitter, although its exact role is uncertain (4, 9-13). To understand the influence of photoperiod on GABAergic function, we studied synaptic activity, using patch clamp, and GABAergic responses, using Ca 2+ imaging techniques, in the SCN of mice adjusted to long-day and short-day photoperiods. We hypothesized that the narrow, synchronized phase distribution of active neurons during short-day photoperiods would result in increased synaptic activity during the day. Surprisingly, however, exposure to a short-day photoperiod decreased the frequency of spontaneous GABAergic synaptic events compared with the long-day photoperiod.Subsequently, we tested the effect of photoperiod on GABAinduced excitation in the SCN neuronal network. Ca 2+ transients were measured in response to GABA stimulation in long-day and short-day photoperiods. Interestingly, of all cells from the long-day photoperiod, 40% were excitatory and 36% were inhibitory. In contrast, in the short-day photoperiod, 28% of the c...

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mentioning

confidence: 99%

Seasonal induction of GABAergic excitation in the central mammalian clock

Farajnia

Westering

Meijer

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

107

129

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“…and libido, and changes in eating behaviour [10,6]. From a Neuroendocrinological perspective, median cortisol levels are lowest in the summer solstice quarter and over 8.5% higher in the winter solstice quarter [4].…”

Section: Resultsmentioning

confidence: 99%

Seasonal Variation in Collective Mood via Twitter Content and Medical Purchases

Dzogang

Goulding

Lightman

et al. 2017

Advances in Intelligent Data Analysis XVI

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Abstract. The analysis of sentiment contained in vast amounts of Twitter messages has reliably shown seasonal patterns of variation in multiple studies, a finding that can have great importance in the understanding of seasonal affective disorders, particularly if related with known seasonal variations in certain hormones. An important question, however, is that of directly linking the signals coming from Twitter with other sources of evidence about average mood changes. Specifically we compare Twitter signals relative to anxiety, sadness, anger, and fatigue with purchase of items related to anxiety, stress and fatigue at a major UK Health and Beauty retailer. Results show that all of these signals are highly correlated and strongly seasonal, being under-expressed in the summer and over-expressed in the other seasons, with interesting differences and similarities across them. Anxiety signals, extracted from both Twitter and from Health product purchases, peak in spring and autumn, and correlate also with the purchase of stress remedies, while Twitter sadness has a peak in the Winter, along with Twitter anger and remedies for fatigue. Surprisingly, purchase of remedies for fatigue do not match the Twitter fatigue, suggesting that perhaps the names we give to these indicators are only approximate indications of what they actually measure. This study contributes both to the clarification of the mood signals contained in social media, and more generally to our understanding of seasonal cycles in collective mood.

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“…One mechanism by which light may alter the response to stress is through changes in immunity: photoimmunomodulation (4,5,10,11,17,18,40). The neutrophil is a fundamental effector of organ injury during I/R, and inhibiting neutrophil influx or function during I/R markedly reduces organ injury (20)(21)(22).…”

Section: Discussionmentioning

confidence: 99%

“…Fish raised under light of blue/green spectrum exhibited reduced oxidative stress by comparison with environmental red light (13,14). And a novel paradigm posits that seasonal variation in environmental stress (e.g., thermal, starvation) evolutionarily selected animals expressing photoperiodism: the ability to interpret environmental day length (17,18). Responding to a progressively shorter photoperiod, energetic resources are concentrated in endogenous mechanisms (i.e., immune function) necessary for seasonally appropriate survival strategies.…”

mentioning

confidence: 99%

Blue light reduces organ injury from ischemia and reperfusion

Yuan

Collage

Huang

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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Evidence suggests that light and circadian rhythms profoundly influence the physiologic capacity with which an organism responds to stress. However, the ramifications of light spectrum on the course of critical illness remain to be determined. Here, we show that acute exposure to bright blue spectrum light reduces organ injury by comparison with bright red spectrum or ambient white fluorescent light in two murine models of sterile insult: warm liver ischemia/reperfusion (I/R) and unilateral renal I/R. Exposure to bright blue light before I/R reduced hepatocellular injury and necrosis and reduced acute kidney injury and necrosis. In both models, blue light reduced neutrophil influx, as evidenced by reduced myeloperoxidase (MPO) within each organ, and reduced the release of high-mobility group box 1 (HMGB1), a neutrophil chemotactant and key mediator in the pathogenesis of I/R injury. The protective mechanism appeared to involve an optic pathway and was mediated, in part, by a sympathetic (β3 adrenergic) pathway that functioned independent of significant alterations in melatonin or corticosterone concentrations to regulate neutrophil recruitment. These data suggest that modifying the spectrum of light may offer therapeutic utility in sterile forms of cellular injury.

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Influence of photoperiod on hormones, behavior, and immune function

Cited by 173 publications

References 341 publications

Seasonal induction of GABAergic excitation in the central mammalian clock

Seasonal induction of GABAergic excitation in the central mammalian clock

Seasonal Variation in Collective Mood via Twitter Content and Medical Purchases

Blue light reduces organ injury from ischemia and reperfusion

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