Reproductive hormones and sex chromosomes drive sex differences in the sleep-wake cycle.

There are well-documented gender differences in the risk and severity of sleep disorders and associated comorbidities. While fundamental sex differences in sleep regulatory mechanisms may contribute to gender disparities, biological responses to sleep loss and stress may underlie many of the risks for sleep disorders in women and men. Some of these sex differences appear to be dependent on sex chromosome complement (XX or XY) and the organizational effects of reproductive hormones.

Arginine-vasopressin-expressing neurons in the murine suprachiasmatic nucleus exhibit a circadian rhythm in network coherence in vivo.

The suprachiasmatic nucleus (SCN) is composed of functionally distinct subpopulations of GABAergic neurons which form a neural network responsible for synchronizing most physiological and behavioral circadian rhythms in mammals. To date, little is known regarding which aspects of SCN rhythmicity are generated by individual SCN neurons, and which aspects result from neuronal interaction within a network. Here, we utilize in vivo miniaturized microscopy to measure fluorescent GCaMP-reported calcium dynamics in arginine vasopressin (AVP)-expressing neurons in the intact SCN of awake, behaving mice.

Autonomic Dysfunction Impairs Baroreflex Function in an Alzheimer's Disease Animal Model.

Background: Alzheimer's disease (AD) patients frequently present with orthostatic hypotension. This inability to reflexively increase blood pressure on standing is a serious health concern and increases the risk of stroke and cardiovascular diseases.

Objective: Since there are no clear mechanisms for orthostatic hypotension in human AD, the present study assessed the autonomic changes that could explain this comorbidity in an AD animal model.

Non-rapid eye movement sleep determines resilience to social stress.

Resilience, the ability to overcome stressful conditions, is found in most mammals and varies significantly among individuals. A lack of resilience can lead to the development of neuropsychiatric and sleep disorders, often within the same individual. Despite extensive research into the brain mechanisms causing maladaptive behavioral-responses to stress, it is not clear why some individuals exhibit resilience.

"The ubiquitin ligase SIAH2 is a female-specific regulator of circadian rhythms and metabolism".

Circadian clocks enable organisms to predict and align their behaviors and physiologies to constant daily day-night environmental cycle. Because the ubiquitin ligase Siah2 has been identified as a potential regulator of circadian clock function in cultured cells, we have used SIAH2-deficient mice to examine its function in vivo. Our experiments demonstrate a striking and unexpected sexually dimorphic effect of SIAH2-deficiency on the regulation of rhythmically expressed genes in the liver.