A pilot study of the phase angle between cortisol and melatonin in major depression - a potential biomarker?

Introduction: Hypothalamic-pituitary-adrenal (HPA) axis and melatonin rhythm alterations have been independently reported in major depression (MDD) as well as in insomnia. In this pilot study, we link cortisol and melatonin rhythms and propose that the phase angle between cortisol acrophase (CA) and dim-light melatonin onset (20 pg/ml) (DLMO-20) may yield a useful state specific biomarker for MDD.

Methods: Six healthy (HC) and six depressed (MDD) psychotropic free subjects were admitted to the General Clinical Research Center.

The acute effects of a mineralocorticoid receptor (MR) agonist on nocturnal hypothalamic-adrenal-pituitary (HPA) axis activity in healthy controls.

Introduction: Both glucocorticoid and mineralocorticoid receptors (GRs and MRs) help modulate cortisol feedback on the hypothalamic-adrenal-pituitary (HPA) axis. In brain, MRs inhibit the HPA axis and are thought to be fully occupied. Thus, prior studies of the effects of an MR agonist on HPA axis activity have first used metyrapone to inhibit cortisol production and to consequently deplete the receptors.

Aging and the role of the HPA axis and rhythm in sleep and memory-consolidation.

Changes in the hypothalamo-pituitary-adrenal (HPA) axis and its rhythm with aging have interesting implications for sleep. Herein, the authors review sleep and HPA changes associated with normal aging and point out the similarities in how they change over time. The authors also discuss the effects of sleep on declarative memory consolidation, in particular.

On the interactions of the hypothalamic-pituitary-adrenal (HPA) axis and sleep: normal HPA axis activity and circadian rhythm, exemplary sleep disorders.

The hypothalamic-pituitary-adrenal (HPA) axis plays important roles in maintaining alertness and modulating sleep. Dysfunction of this axis at any level (CRH receptor, glucocorticoid receptor, or mineralocorticoid receptor) can disrupt sleep. Herein, we review normal sleep, normal HPA axis physiology and circadian rhythm, the effects of the HPA axis on sleep, as well as the effects of sleep on the HPA axis.

Human cutaneous vascular responses to whole-body tilting, Gz centrifugation, and LBNP.

We hypothesized that gravitational stimuli elicit cardiovascular responses in the following order with gravitational stress equalized at the level of the feet, from lowest to highest response: short-(SAC) and long-arm centrifugation (LAC), tilt, and lower body negative pressure (LBNP). Up to 15 healthy subjects underwent graded application of the four stimuli. Laser-Doppler flowmetry measured regional skin blood flow.