Dynamics of ACTH and Cortisol Secretion and Implications for Disease

Endocrine Reviews, Год журнала: 2020, Номер 41(3)

Опубликована: Фев. 15, 2020

Abstract The past decade has seen several critical advances in our understanding of hypothalamic–pituitary–adrenal (HPA) axis regulation. Homeostatic physiological circuits need to integrate multiple internal and external stimuli provide a dynamic output appropriate for the response parameters their target tissues. HPA is an example such homeostatic system. Recent studies have shown that circadian rhythmicity major this system—the adrenal glucocorticoid hormones corticosterone rodent predominately cortisol man—comprises varying amplitude pulses exist due subhypothalamic pulse generator. Oscillating endogenous signals interact with regulatory systems within individual parts including gland itself, where network can further modify pulsatile release hormone. form oscillating signal needs be decoded at cellular level. If abolished by administration long-acting synthetic glucocorticoid, resulting disruption regulation potential negatively impact many glucocorticoid-dependent bodily systems. Even subtle alterations dynamics system, during chronic stress or certain disease states, potentially result changes functional cells tissues throughout body, altering metabolic processes, behavior, affective state, cognitive function susceptible individuals. recent development novel chronotherapy, which deliver both ultradian patterns, provides great promise patients on treatment.

Язык: Английский

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Melanopsin and the Intrinsically Photosensitive Retinal Ganglion Cells: Biophysics to Behavior

Neuron, Год журнала: 2019, Номер 104(2), С. 205 - 226

Опубликована: Окт. 1, 2019

Язык: Английский

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Light and Cognition: Roles for Circadian Rhythms, Sleep, and Arousal

Frontiers in Neurology, Год журнала: 2018, Номер 9

Опубликована: Фев. 8, 2018

Light exerts a wide range of effects on mammalian physiology and behaviour. As well as synchronising circadian rhythms to the external environment, light has been shown modulate autonomic neuroendocrine responses regulating sleep influencing cognitive processes such attention, arousal performance. The last two decades have seen major advances in our understanding retinal photoreceptors that mediate these non-image forming light, neural pathways molecular mechanisms by which are generated entrained light/dark (LD) cycle. By contrast, lighting influences more equivocal. different complex. direct indirect may also occur due disrupted entrainment. Despite widespread use LD cycles study role cognition, experimental protocols used subtly function not comparable. Moreover, will disrupt alter physiological arousal, both known cognition. Studies behavioural assays dependent upon sensory processes, contribute their variable findings. Here we propose studies addressing conditions must account for rhythms, if fully understand basis effects.

Язык: Английский

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New Insights Into the Circadian Rhythm and Its Related Diseases

Frontiers in Physiology, Год журнала: 2019, Номер 10

Опубликована: Июнь 25, 2019

Circadian rhythms (CR) are a series of endogenous autonomous oscillators generated by the molecular circadian clock which acting on coordinating internal time with external environment in 24-h daily cycle. The system is major regulatory factor for nearly all physiological activities and its disorder has severe consequences human health. CR disruption common issue modern society, researches about people jet lag or shift works have revealed that can cause cognitive impairment, psychiatric illness, metabolic syndrome, dysplasia, cancer. In this review, we summarized synchronizers synchronization methods used experimental research, introduced monitoring detection methods. Moreover, evaluated conventional databases, analyzed experiments characterized underlying causes disorder. Finally, further discussed latest developments understanding disruption, how it may be relevant to health disease. Briefly, review aimed synthesize previous studies aid future CR-related diseases.

Язык: Английский

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Light and the laboratory mouse

Journal of Neuroscience Methods, Год журнала: 2017, Номер 300, С. 26 - 36

Опубликована: Апрель 14, 2017

Light exerts widespread effects on physiology and behaviour. As well as the widely-appreciated role of light in vision, also plays a critical many non-visual responses, including regulating circadian rhythms, sleep, pupil constriction, heart rate, hormone release learning memory. In mammals, responses to are all mediated via retinal photoreceptors, classical rods cones involved vision recently identified melanopsin-expressing photoreceptive ganglion cells (pRGCs). Understanding laboratory mouse therefore depends upon an appreciation these their differing sens itivities absolute levels wavelengths. The signals from photoreceptors often integrated, with different involving distinct projections, making generalisations challenging. Furthermore, commonly used strains carry mutations that affect visual or physiology, ranging inherited degeneration genetic differences sleep rhythms. Here we provide overview systems before discussing practical considerations for use researchers animal facility staff working mice.

Язык: Английский

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The cognitive impact of light: illuminating ipRGC circuit mechanisms

Nature reviews. Neuroscience, Год журнала: 2024, Номер 25(3), С. 159 - 175

Опубликована: Янв. 26, 2024

Язык: Английский

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Light, Alertness, and Alerting Effects of White Light: A Literature Overview

Journal of Biological Rhythms, Год журнала: 2018, Номер 33(6), С. 589 - 601

Опубликована: Сен. 7, 2018

Light is known to elicit non-image-forming responses, such as effects on alertness. This has been reported especially during light exposure at night. Nighttime results might not be translatable the day. article aims provide an overview of (1) neural mechanisms regulating alertness, (2) ways measuring and quantifying (3) current literature specifically regarding different intensities white various measures correlates alertness daytime. In general, present provides inconclusive alerting intensity daytime, particularly for objective However, research paradigms employed in earlier studies differed substantially, most tested only a limited set lighting conditions. Therefore, potential more intense should investigated systematic, dose-dependent manner with multiple within one experimental paradigm over course

Язык: Английский

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Assessing mouse behaviour throughout the light/dark cycle using automated in-cage analysis tools

Journal of Neuroscience Methods, Год журнала: 2017, Номер 300, С. 37 - 47

Опубликована: Апрель 26, 2017

An important factor in reducing variability mouse test outcomes has been to develop assays that can be used for continuous automated home cage assessment. Our experience shown this most evidenced long-term assessment of wheel-running activity mice. Historically, mice and other rodents have as a robust assay determine, with precision, the inherent period circadian rhythms Furthermore, instrumental dissecting molecular genetic basis mammalian rhythms. In teasing out elements determined its robustness – an unforced behaviour over long time intervals we others investigating whether similar apparatus could accurately discriminate differences distinct behavioural parameters Firstly, using these systems, explored behaviours number inbred strains determine extract biologically meaningful differences. Secondly, tested relevant mutant lines how discriminative were. findings show that, when compared conventional out-of-cage phenotyping, far deeper understanding phenotype established by monitoring one or more light:dark cycles.

Язык: Английский

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Unconventional Roles of Opsins

Annual Review of Cell and Developmental Biology, Год журнала: 2017, Номер 33(1), С. 241 - 264

Опубликована: Июнь 9, 2017

Rhodopsin is the classical light sensor. Although rhodopsin has long been known to be important for image formation in eye, requirements opsins non–image and extraocular sensation were revealed much later. Most recent demonstration that an opsin fruit fly, Drosophila melanogaster, expressed pacemaker neurons brain functions entrainment of circadian rhythms. However, biggest surprise have light-independent roles, countering more than a century dogma they function exclusively as sensors. Through studies Drosophila, roles emerged temperature hearing. these findings uncovered there are hints wide array animals, including mammals. Thus, despite decades focus on detectors, represent new class polymodal sensory receptor.

Язык: Английский

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Circadian Photoentrainment in Mice and Humans

Biology, Год журнала: 2020, Номер 9(7), С. 180 - 180

Опубликована: Июль 21, 2020

Light around twilight provides the primary entrainment signal for circadian rhythms. Here we review mechanisms and responses of mouse human systems to light. Both utilize a network photosensitive retinal ganglion cells (pRGCs) expressing photopigment melanopsin (OPN4). In both species action spectra functional expression OPN4 in vitro show that has λmax close 480 nm. Anatomical findings demonstrate there are multiple pRGC sub-types, with some evidence mice, but little humans, regarding their roles regulating physiology behavior. Studies non-human primates rods cones project can modulate light pRGCs. Such an integration signals enables detect dim light, higher intensities intermittent exposure, whilst measures bright over extended periods time. Although photoreceptor similar, sensitivity thresholds differ markedly between mice humans. Mice entrain at approximately 1 lux few minutes, humans require high irradiance (>100's lux) long duration (>30 min). The basis this difference remains unclear. As our exposure is highly dynamic, because interactions complex difficult model, attempts develop evidence-based lighting enhance very challenging. A way forward will be define artificial natural "real world" where intensity, duration, spectral quality, time day, history age each assessed.

Язык: Английский

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