No abstract

Cortisol modulates brain functions in humans. This principal endogenous glucocorticoid in humans decreases rapid-eye-movement (REM) sleep and increases slow-wave sleep (SWS). Because cortisol exerts its effect on brain functions via mineralocorticoid receptors (MR) and glucocorticoid receptors (GR), we were interested in which type of corticosteroid receptor mediates these steroid effects on sleep. Healthy men were tested in two double-blind experiments. In experiment I (n = 8), the subject's sleep was tested during four nights: 1) after pretreatment with dexamethasone (Dex, 4 mg/day) for 4 or 6 days and after additional infusion of placebo or cortisol (10 mg/h) during the experimental night, 2) after pretreatment with placebo for 4 or 6 days and after infusion of placebo or cortisol (10 mg/h) during the experimental night. In experiment II, subjects (n = 10) slept after intravenous administration of potassium canrenoate (200 mg, at 0800 and 1700 h before experimental nights) or placebo. Cortisol infusion moderately increased the percentage of SWS (P less than 0.05) and markedly decreased REM sleep (P less than 0.01); influence of cortisol on SWS did not depend on pretreatment with Dex. Dex reduced both SWS and REM sleep (P less than 0.05). Canrenoate markedly diminished SWS (P less than 0.01) but left REM sleep unaffected. The results suggest that corticosteroid-induced changes in SWS are mediated via MR-like central receptors in humans, whereas changes in REM sleep involve GR.

Our observations have important implications with respect to the potential weight-reducing actions of nesfatin-1/NUCB-2 treatment. Future research should seek to clarify whether nesfatin-1/NUCB-2 would be beneficial in the management of obesity.

Ibuprofen pharmacokinetics showed a large interindividual variation in premature infants during treatment for patent ductus arteriosus, and significant changes may occur between day 3 and day 5 after birth in those infants with a closing ductus. These findings may have implications for the treatment schedule with ibuprofen in patients with patent ductus arteriosus.