Related Experiment Video
Updated: Sep 11, 2026

A Chronic Sleep Fragmentation Model using Vibrating Orbital Rotor to Induce Cognitive Deficit and Anxiety-Like Behavior in Young Wild-Type Mice
Published on: September 22, 2020
Melatonin rhythmicity: effect of age and Alzheimer's disease
1School of Biomedical and Life Sciences, University of Surrey, Guildford GU2 7XH, UK. d.skene@surrey.ac.uk
Abstract:
The circadian rhythm of the pineal gland hormone, melatonin is generated within the hypothalamic suprachiasmatic nuclei (SCN), site of the circadian clock. The circadian clock and its output melatonin rhythm is synchronized to the 24h day by environmental light which is transmitted from the retina to the SCN primarily via the retinohypothalamic tract. Changes in both the amplitude and timing of the melatonin rhythm have been reported with aging in humans. Whether these age-related changes (reduced melatonin amplitude, earlier timing of melatonin rhythm) are a result of aging of the retina, the SCN clock, the pineal gland, their neural connections or a combination of some or all of these is not known. The fragmented sleep/wake patterns observed in the elderly and to a greater extent in patients with Alzheimer's disease have been shown to be partly related to an altered retina-SCN-pineal axis. Therapies designed to reinforce the circadian axis (for example, administration of melatonin or light) have been reported to alleviate the disturbed circadian rhythms and disrupted sleep. Future research needs to pinpoint the site(s) of age-related dysfunction so that therapies can be specifically tailored to correct the abnormality in addition to reinforcing any of the intact processes.
More Related Videos
05:59High-Throughput Small Molecule Drug Screening For Age-Related Sleep Disorders Using Drosophila melanogaster
Published on: October 20, 2023
12:06Transmission Electron Microscopy as the Visualization Technique for Analysis of Circadian Synaptic Plasticity in the Mouse Barrel Cortex
Published on: August 19, 2025
Related Concept Videos
Circadian Rhythms and Gene Regulation
Alzheimer's Disease: Overview
The clinical diagnosis of AD hinges on the presence of memory and other cognitive impairments. Biomarkers, such as changes in Aβ and tau...
Management of Insomnia
Chronopharmacokinetics: Circadian Rhythms and Influence on Drug Response
The time of drug administration is an important factor to consider, as it can influence the toxic dose of a drug. For example, a study conducted by Prins et al. in 1997 examined the effects of the timing of...
Alzheimer Disease l: Introduction
Alzheimer Disease ll: Pathophysiology