Lithium affects the circadian clock in the choroid plexus - A new role for an old mechanism.

Lithium is an effective mood stabilizer, but the mechanism of its therapeutic action is not well understood. We investigated the effect of lithium on the circadian clock located in the ventricle barrier complex containing the choroid plexus (CP), a part of the glymphatic system that influences gross brain function via the production of cerebrospinal fluid. The mPer2 mice were injected with lithium chloride (LiCl) or vehicle, and their effects on the clock gene Nr1d1 in CP were detected by RT qPCR.

High Sensitivity of the Circadian Clock in the Hippocampal Dentate Gyrus to Glucocorticoid- and GSK3-Beta-Dependent Signals.

Aims: Circadian clocks in the hippocampus (HPC) align memory processing with appropriate time of day. Our study was aimed at ascertaining the specificity of glycogen synthase kinase 3-beta (GSK3β)- and glucocorticoid (GC)-dependent pathways in the entrainment of clocks in individual HPC regions, CA1-3, and dentate gyrus (DG).

Methods: The role of GCs was addressed in vivo by comparing the effects of adrenalectomy (ADX) and subsequent dexamethasone (DEX) supplementation on clock gene expression profiles (Per1, Per2, Nr1d1, and Bmal1).

Hormonal fine-tuning of clock in decidual region of mouse placenta by dopamine, melatonin, insulin, leptin and ghrelin.

Introduction: The maternal part of the rodent placenta harbors a circadian clock which robustly responds to glucocorticoids, however, its sensitivity to other hormones has not been elucidated. In this study, we tested five selected hormones (dopamine, melatonin, insulin, leptin and ghrelin) for their effectiveness to affect the clock in decidual region of mouse placenta in vitro.

Methods: We administered the hormones or corresponding vehicles at various time points over 24 h to organotypic placental explants of mPer2 mice containing the decidua basalis (DB) region and monitored their effects on amplitude, period, median expression level (mesor) and phase of PER2-driven bioluminescence rhythms.

Challenging the Integrity of Rhythmic Maternal Signals Revealed Gene-Specific Responses in the Fetal Suprachiasmatic Nuclei.

During fetal stage, maternal circadian system sets the phase of the developing clock in the suprachiasmatic nuclei (SCN) via complex pathways. We addressed the issue of how impaired maternal signaling due to a disturbed environmental light/dark (LD) cycle affects the fetal SCN. We exposed pregnant Wistar rats to two different challenges - a 6-h phase shift in the LD cycle on gestational day 14, or exposure to constant light (LL) throughout pregnancy - and detected the impact on gene expression profiles in 19-day-old fetuses.