Chemical Neuroanatomy of the Mammalian Circadian System

1997 ◽  
pp. 79-93 ◽  
Author(s):  
R. Y. Moore
Keyword(s):  
Circadian System ◽  
Chemical Neuroanatomy

scholarly journals Genome-wide correlation analysis to identify amplitude regulators of circadian transcriptome output

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Evan S. Littleton ◽  
Madison L. Childress ◽  
Michaela L. Gosting ◽  
Ayana N. Jackson ◽  
Shihoko Kojima
Keyword(s):  
Clock Genes ◽  
Circadian System ◽  
Average Level ◽  
Relative Amplitude ◽  
Critical Component ◽  
Period 2 ◽  
Genome Wide ◽  
Mouse Tissues ◽  
Rhythmic Gene ◽  
Insight Into

AbstractCell-autonomous circadian system, consisting of core clock genes, generates near 24-h rhythms and regulates the downstream rhythmic gene expression. While it has become clear that the percentage of rhythmic genes varies among mouse tissues, it remains unclear how this variation can be generated, particularly when the clock machinery is nearly identical in all tissues. In this study, we sought to characterize circadian transcriptome datasets that are publicly available and identify the critical component(s) involved in creating this variation. We found that the relative amplitude of 13 genes and the average level of 197 genes correlated with the percentage of cycling genes. Of those, the correlation of Rorc in both relative amplitude and the average level was one of the strongest. In addition, the level of Per2AS, a novel non-coding transcript that is expressed at the Period 2 locus, was also linearly correlated, although with a much lesser degree compared to Rorc. Overall, our study provides insight into how the variation in the percentage of clock-controlled genes can be generated in mouse tissues and suggests that Rorc and potentially Per2AS are involved in regulating the amplitude of circadian transcriptome output.

Photic Regulation of Circadian Rhythms and Voluntary Ethanol Intake: Role of Melanopsin-expressing Intrinsically Photosensitive Retinal Ganglion Cells

2020 ◽  
pp. 074873042098122
Author(s):  
Matthew C. Hartmann ◽  
Walter D. McCulley ◽  
Samuel T. Johnson ◽  
Corey S. Salisbury ◽  
Nikhil Vaidya ◽  
...  
Keyword(s):  
Retinal Ganglion Cells ◽  
Ganglion Cells ◽  
Circadian System ◽  
Genetically Engineered ◽  
Ethanol Intake ◽  
Constant Darkness ◽  
Retinal Ganglion ◽  
Retinal Photoreceptors ◽  
Genetically Engineered Mouse Model ◽  
Lighting Regimen

“Non-image-forming” (NIF) effects of light are mediated primarily by a subset of intrinsically photosensitive retinal ganglion cells (ipRGCs) expressing the photopigment, melanopsin (OPN4). These NIF functions include circadian entrainment, pupillary reflexes, and photic effects on sleep, mood, and cognition. We recently reported that mice of multiple genotypes exhibit reduced voluntary ethanol intake under both constant darkness (DD) and constant light (LL) relative to standard light-dark (LD) conditions. In the present study, we sought to determine whether these effects are mediated by melanopsin-expressing ipRGCs and their potential relationship to photic effects on the circadian system. To this end, we examined the effects of environmental lighting regimen on both ethanol intake and circadian activity rhythms in a genetically engineered mouse model ( Opn4aDTA/aDTA) in which melanopsin expression is completely blocked while ipRGCs are progressively ablated due to activation of attenuated diphtheria toxin A (aDTA) transgene under the control of the Opn4 promoter. As expected from previous studies, Opn4aDTA/aDTA mice displayed dramatic attenuation of circadian photosensitivity, but surprisingly, showed identical suppression of ethanol intake under both DD and LL as that seen in controls. These results demonstrate that the effects of lighting regimen on voluntary ethanol intake are independent of melanopsin-expressing ipRGCs and ipRGC-mediated photic effects on the circadian system. Rather, these effects are likely mediated by classical retinal photoreceptors and central pathways.

Organization of the circadian system in the subterranean mole rat, Cryptomys hottentotus (Bathyergidae)

2003 ◽  
Vol 967 (1-2) ◽  
pp. 48-62 ◽  
Author(s):  
Julia Negroni ◽  
Nickel C Bennett ◽  
Howard M Cooper
Keyword(s):  
Circadian System ◽  
Mole Rat ◽  
Subterranean Mole Rat

scholarly journals Oxidative Dysregulation in Early Life Stress and Posttraumatic Stress Disorder: A Comprehensive Review

2021 ◽  
Vol 11 (6) ◽  
pp. 723
Author(s):  
Evangelos Karanikas ◽  
Nikolaos P. Daskalakis ◽  
Agorastos Agorastos
Keyword(s):  
Traumatic Stress ◽  
Life Stress ◽  
Redox State ◽  
Stress Disorder ◽  
Early Life Stress ◽  
Circadian System ◽  
Clinical Genetic ◽  
Knowledge Growth ◽  
Substantial Heterogeneity ◽  
Pituitary Adrenal Axis

Traumatic stress may chronically affect master homeostatic systems at the crossroads of peripheral and central susceptibility pathways and lead to the biological embedment of trauma-related allostatic trajectories through neurobiological alterations even decades later. Lately, there has been an exponential knowledge growth concerning the effect of traumatic stress on oxidative components and redox-state homeostasis. This extensive review encompasses a detailed description of the oxidative cascade components along with their physiological and pathophysiological functions and a systematic presentation of both preclinical and clinical, genetic and epigenetic human findings on trauma-related oxidative stress (OXS), followed by a substantial synthesis of the involved oxidative cascades into specific and functional, trauma-related pathways. The bulk of the evidence suggests an imbalance of pro-/anti-oxidative mechanisms under conditions of traumatic stress, respectively leading to a systemic oxidative dysregulation accompanied by toxic oxidation byproducts. Yet, there is substantial heterogeneity in findings probably relative to confounding, trauma-related parameters, as well as to the equivocal directionality of not only the involved oxidative mechanisms but other homeostatic ones. Accordingly, we also discuss the trauma-related OXS findings within the broader spectrum of systemic interactions with other major influencing systems, such as inflammation, the hypothalamic-pituitary-adrenal axis, and the circadian system. We intend to demonstrate the inherent complexity of all the systems involved, but also put forth associated caveats in the implementation and interpretation of OXS findings in trauma-related research and promote their comprehension within a broader context.

scholarly journals The circadian clock uses different environmental time cues to synchronize emergence and locomotion of the solitary bee Osmia bicornis

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Katharina Beer ◽  
Mariela Schenk ◽  
Charlotte Helfrich-Förster ◽  
Andrea Holzschuh
Keyword(s):  
Circadian Clock ◽  
Circadian System ◽  
Evolutionary Adaptation ◽  
Solitary Bee ◽  
Daily Rhythms ◽  
Osmia Bicornis ◽  
Cavity Nesting ◽  
Impact On Survival ◽  
Life On Earth ◽  
And Behavior

AbstractLife on earth adapted to the daily reoccurring changes in environment by evolving an endogenous circadian clock. Although the circadian clock has a crucial impact on survival and behavior of solitary bees, many aspects of solitary bee clock mechanisms remain unknown. Our study is the first to show that the circadian clock governs emergence in Osmia bicornis, a bee species which overwinters as adult inside its cocoon. Therefore, its eclosion from the pupal case is separated by an interjacent diapause from its emergence in spring. We show that this bee species synchronizes its emergence to the morning. The daily rhythms of emergence are triggered by temperature cycles but not by light cycles. In contrast to this, the bee’s daily rhythms in locomotion are synchronized by light cycles. Thus, we show that the circadian clock of O. bicornis is set by either temperature or light, depending on what activity is timed. Light is a valuable cue for setting the circadian clock when bees have left the nest. However, for pre-emerged bees, temperature is the most important cue, which may represent an evolutionary adaptation of the circadian system to the cavity-nesting life style of O. bicornis.

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