Like many wild species, the European hamster (Cricetus cricetus) adapts to the marked seasonal changes in its environment, namely by hibernation and inhibition of sexual activity in winter. These annual functions are driven by the variation in the environmental factors (light, temperature) that are transmitted to the body through large variations in the duration and amplitude of the nocturnal m...

Small nectarivorous vertebrates face a quandary. When feeding, they must eliminate prodigious quantities of water; however, when they are not feeding, they are susceptible to dehydration. We examined the role of the kidney in the resolution of this osmoregulatory dilemma. Broad-tailed hummingbirds (Selasphorus platycercus) displayed diurnal variation in glomerular filtration rate (GFR). During ...

The aim of this study was to determine the chronobiological variations of cytokines (IFN-γ, TGF-β) and hormones (melatonin and cortisol). The sample was collected from 42 mothers at three stages of maturity-day 3 (colostrum), day 10 (transitional milk) and day 30 (mature milk) postpartum, at two times of day: diurnal (12:00 h) and nocturnal (24:00 h), resulting a total of 252 samples. Melatonin...

Plant respiration can theoretically be fueled by and dependent upon an array of central metabolism components; however, which ones are responsible for the quantitative variation found in respiratory rates is unknown. Here, large-scale screens revealed 2-fold variation in nighttime leaf respiration rate (RN) among mature leaves from an Arabidopsis (Arabidopsis thaliana) natural accession collect...

We studied the within-night variability of the maximum esophageal pressure deflection before apnea termination (DPmax) in nine patients with severe obstructive sleep apnea as an index of the arousal threshold and the mean electroencephalogram (EEG) delta power for each 30 s as an index of the timing of sleep cycles. Periodicity in the time variation of delta power and DPmax was analyzed by dete...