Suprachiasmatic nucleus

…(LL) during EDS on the clock in the suprachiasmatic nucleus (SCN) of male and female mice naturally deficient in melatonin. We used PER2::LUC knock-in mice, which allows monitoring of clock function in organotypic explants ex vivo. First, we showed that the SC

The suprachiasmatic nucleus (SCN) is the central circadian clock, governing physiological processes through its output to the subparaventricular zone (SPZ). We investigated functional synaptic connectivity between the SCN and the SPZ neurons in mouse brain slices and we studied the effects of peptides expressed in the SCN on the SPZ neurons. Photostimulation of SCN neuromedin-S (NMS) neurons or the vasoactive intestinal peptide (VIP) neurons induced opto-evoked inhibitory post-synaptic currents (oIPSCs) in 60% and 50% of recorded SPZ neurons, respectively. These responses were mediated by GABA

…circadian system centered around the suprachiasmatic nucleus, while fish present a more distributed system with tissues directly responding to sunlight. Through mRNA-sequencing and promoter analysis, we explored the cellular transcriptional response to sunlight in zebrafish (D. rerio) and blind cavefish (P. andruzzii), the latter servin

Vasopressin (VP) production in the Suprachiasmatic Nucleus (SCN) is influenced by the rhythm of clock genes and the light-dark cycle. The circadian production and release of VP from SCN terminals is one of the core signals via which the biological clock imposes its rhythm on its target structures. It is a critical element in the circadian regulation of corticosterone secretion, reproductive cycle, and metabolism in rodents. All these circadian variables are regulated within very narrow boundaries at a specific time of the day, indicating the need for an elaborate feedback system to inform the

…The suprachiasmatic nucleus (SCN) governs biological rhythms and receives direct retinal input via melanopsin-expressing retinal ganglion cells (mRGCs) to synchronize with environmental light cycles. The anatomical and functional basis for circadian disruption in AD remains unclear. Here, we explore the relationships between non-visual photoreception, SCN connectome evolution, and sleep regulation in the APP/PS1 mouse model.We measured mRGCs' light-in

The circadian release of endogenous glucocorticoids is essential in preparing and synchronizing the body’s daily physiological needs. Disruption in the rhythmic activity of glucocorticoids has been observed in individuals with a variety of cancer types, and blunting of this rhythm has been shown to predict cancer mortality and declines in quality of life. This suggests that a disrupted glucocorticoid rhythm is potentially a shared phenotype across cancers. However, where this phenomenon is driven by the cancer itself, and the causal mechanisms that link glucocorticoid rhythm dysfunction and c

Circadian clocks dominate our lives. By creating and distributing an internal representation of 24-hour solar time, they prepare us, and thereby adapt us, to the daily and seasonal world. Jet-lag is an obvious indicator of what can go wrong when such adaptation is disrupted acutely. More seriously, the growing prevalence of rotational shift-work which runs counter to our circadian life, is a significant chronic challenge to health, presenting as increased incidence of systemic conditions such as metabolic and cardiovascular disease. Added to this, circadian and sleep disturbances are a recogni

Neurons in the suprachiasmatic nucleus (SCN, the brain’s master circadian clock) display a 24 hour cycle in the their rate of action potential discharge whereby firing rates are high during the light phase and lower during the dark phase. Although it is generally agreed that this cycle of activity is a key mediator of the clock’s neural and humoral output, surprisingly little is known about how changes in clock electrical activity can mediate scheduled physiological changes at different times of day. Using opto- and chemogenetic approaches in mice we have shown that the onset of electrical act

…24 hour world are controlled by the suprachiasmatic nucleus (SCN), the brain's central circadian clock. And yet, the SCN consists of only 20,000 neurons and astrocytes, so what makes it such a powerful clock, able to set the tempo to our lives? Professor Hastings will consider the cell-autonomus and neural circuit-level mechanisms that sustain the SCN clock and how it regulates rest, activity and sleep.