Changes in the expression of steroid metabolism-related genes in rat adrenal glands during selective REM sleep deprivation

The Role of Sleep Deprivation in Arrhythmias

Sleep is essential to the normal psychological and physiological activities of the human body. Increasing evidence indicates that sleep deprivation is associated with the occurrence, development, and poor treatment effects of various arrhythmias. Sleep deprivation affects not only the peripheral nervous system but also the central nervous system, which regulates the occurrence of arrhythmias. In addition, sleep deprivation is associated with apoptotic pathways, mitochondrial energy metabolism disorders, and immune system dysfunction. Although studies increasingly suggest that pathological sleep patterns are associated with various atrial and ventricular arrhythmias, further research is needed to identify specific mechanisms and recommend therapeutic interventions. This review summarizes the findings of sleep deprivation in animal experiments and clinical studies, current challenges, and future research directions in the field of arrhythmias.

Sleep deprivation and gene expression

Sleep occurs in a wide range of animal species as a vital process for the maintenance of homeostasis, metabolic restoration, physiological regulation, and adaptive cognitive functions in the central nervous system. Long-term perturbations induced by the lack of sleep are mostly mediated by changes at the level of transcription and translation. This chapter reviews studies in humans, rodents, and flies to address the various ways by which sleep deprivation affects gene expression in the nervous system, with a focus on genes related to neuronal plasticity, brain function, and cognition. However, the effects of sleep deprivation on gene expression and the functional consequences of sleep loss are clearly not restricted to the cognitive domain but may include increased inflammation, expression of stress-related genes, general impairment of protein translation, metabolic imbalance, and thermal deregulation.

Adrenocortical dysregulation as a major player in insulin resistance and onset of obesity

The aim of this review is to explore the dysregulation of adrenocortical secretions as a major contributor in the development of obesity and insulin resistance. Disturbance of adipose tissue physiology is one of the primary events in the development of pathologies associated with the metabolic syndrome, such as obesity and type 2 diabetes. Several studies indicate that alterations in metabolism of glucocorticoids (GC) and androgens, as well as aldosterone in excess, are involved in the emergence of metabolic syndrome. Cross talk among adipose tissue, the hypothalamo-pituitary complex, and adrenal gland activity plays a major role in the control of food intake, glucose metabolism, lipid storage, and energy balance. Perturbation of this cross talk induces alterations in the regulatory mechanisms of adrenocortical steroid synthesis, secretion, degradation, and/or recycling, at the level of the zonae glomerulosa (aldosterone), fasciculata (GC and GC metabolites), and reticularis (androgens and androgen precursors DHEA and DHEAS). As a whole, these adrenocortical perturbations contribute to the development of metabolic syndrome at both the paracrine and systemic level by favoring the physiological dysregulation of organs responsive to aldosterone, GC, and/or androgens, including adipose tissue.

Toluene inhalation-induced adrenocortical hypertrophy and endocrinological changes in rat

Rats were exposed to toluene (1,500 ppm for 4 hr per day) for 7 days. The body weight of the rats was significantly lower and the weight of the adrenal gland was significantly higher in the toluene inhalation group compared to the controls. Microscopically, there was no obvious change in the medulla, but hypertrophy of the cortex was observed in the toluene inhalation group. And, the size of adrenocortical cells in treated-rats was also significantly enlarged than the control. Immunohistochemical staining did not show a clear difference in localization of aldosterone-positive cells between the control and inhalation groups. Expansion of the corticosterone-positive area consistent with the cortical hypertrophy was recognized in the inhalation group. Enhancement of 72 kD-heat-shock protein (HSP70)-expression in the toluene inhalation group was not observed. Neither stress nor damage to cortical cells due directly to toluene exposure was observed in the cortex. Also, there was no obvious difference in the anti-proliferating cell nucleus antigen (PCNA)-immunostaining between control and inhalation groups. Thus, it is suspected that cortical hypertrophy was the result of cell enlargement due to the stimulation of the cortical cells. Corticotropin-releasing factor (CRF) immunoreactivity in the paraventricular nucleus (PVN) was increased in the inhalation group. Concentration of plasma ACTH was elevated significantly by toluene exposure. The amounts of mRNA of adrenocortical steroid metabolism gene, cytochrome side-chain cleavage (P450scc), was also increased by toluene inhalation. Toluene exposure might induce adrenocortical hypertrophy via the hypothalamus-pituitary-adrenal gland (HPA) axis.