Related Experiment Video

Updated: Jul 18, 2026

In Vivo Monitoring of Circadian Clock Gene Expression in the Mouse Suprachiasmatic Nucleus Using Fluorescence Reporters
07:44

In Vivo Monitoring of Circadian Clock Gene Expression in the Mouse Suprachiasmatic Nucleus Using Fluorescence Reporters

Published on: July 4, 2018

Loss of responsiveness to melatonin in the aging mouse suprachiasmatic nucleus

Charlotte von Gall1, David R Weaver

  • 1Department of Neurobiology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01605, USA. vongall@med.uni-frankfurt.de

Neurobiology of Aging
|November 25, 2006
PubMed

Insights

Aging reduces the effectiveness of melatonin signaling in the brain's circadian clock. Melatonin loses its ability to inhibit CREB phosphorylation in aged mice, impacting sleep regulation in older humans.

Area of Science:

  • Neuroscience
  • Chronobiology

Background:

  • Melatonin is a key hormone regulating circadian rhythms.
  • The suprachiasmatic nucleus (SCN) is central to melatonin's action.
  • PACAP-induced CREB phosphorylation is a marker for SCN melatonin receptor activity.

Purpose of the Study:

  • To investigate the impact of aging on melatonin responsiveness in the mouse SCN.
  • To determine if melatonin's inhibitory effect on CREB phosphorylation diminishes with age.

Main Methods:

  • Prepared SCN slices from young and aged mice.
  • Treated slices with PACAP alone or PACAP plus melatonin.
  • Assessed CREB phosphorylation using immunohistochemistry.

Main Results:

  • Melatonin dose-dependently inhibited PACAP-induced CREB phosphorylation in young mice.
  • PACAP induced similar CREB phosphorylation levels in aged mice.
  • Melatonin failed to inhibit CREB phosphorylation in aged mice SCN slices.

Conclusions:

  • There is an age-related decline in melatonin sensitivity within the SCN.
  • This loss of sensitivity may contribute to sleep disturbances in the elderly.
  • Findings highlight potential mechanisms for age-related changes in circadian regulation.

Related Concept Videos

Circadian Rhythms and Gene Regulation02:19

Circadian Rhythms and Gene Regulation

The biological clock is involved in many aspects of regulating complex physiology in all animals. It was in 1935 when German zoologists, Hans Kalmus and Erwin Bünning, discovered the existence of circadian rhythm in Drosophila melanogaster. However, the internal molecular mechanisms behind the circadian clock remained a mystery until 1984, when Jeffrey C. Hall, Michael Rosbash, and Michael W. Young discovered the expression of the Per gene oscillating over a 24-hour cycle. In subsequent years,...
Management of Insomnia01:19

Management of Insomnia

The sleep cycle, an integral part of human health, consists of several stages with distinct characteristics and functions. It begins with a transition from wakefulness to sleep, known as the light sleep phase, followed by the restorative deep sleep phase, essential for physical recovery and growth. The cycle concludes with the Rapid Eye Movement (REM) phase, characterized by high brain activity and vivid dreaming. Insomnia, a prevalent sleep disorder, involves difficulty falling asleep, staying...
The Pineal Gland01:02

The Pineal Gland

The pineal gland, a diminutive endocrine structure named for its pinecone-shaped appearance, is situated atop the third ventricle within the diencephalon region of the forebrain. This gland, composed of secretory cells known as pinealocytes arranged in compact cords and clusters around dense particles of calcium salts, plays a pivotal role in hormonal regulation.
The primary secretion of the pineal gland is the hormone melatonin, derived from serotonin. The concentration of melatonin in the...
Biological Clocks and Seasonal Responses02:45

Biological Clocks and Seasonal Responses

The circadian—or biological—clock is an intrinsic, timekeeping, molecular mechanism that allows plants to coordinate physiological activities over 24-hour cycles called circadian rhythms. Photoperiodism is a collective term for the biological responses of plants to variations in the relative lengths of dark and light periods. The period of light-exposure is called the photoperiod.