Timed daily exercise remodels circadian rhythms in mice

Area of Science:

• Neuroscience
• Chronobiology
• Exercise Physiology

Background:

• Circadian rhythms, regulated by the suprachiasmatic nuclei (SCN), are crucial for health.
• The impact of regular exercise on SCN clock cell coordination is not well understood.
• Disrupted circadian rhythms are common in aging and mental illness.

Purpose of the Study:

• To investigate the long-lasting effects of scheduled voluntary exercise (SVE) on SCN clock cell function and behavioral rhythms.
• To determine if SVE can restore circadian function in models with impaired SCN signaling.
• To explore the neurochemical mechanisms underlying exercise's effects on the SCN.

Main Methods:

• Utilized mouse models with intact and impaired SCN intercellular neuropeptide signaling.
• Administered daily scheduled voluntary exercise (SVE).
• Assessed behavioral rhythms, SCN molecular clock activity, and neuronal signaling (including GABAergic).

Main Results:

• SVE promoted SCN clock cell synchrony and robust 24-hour behavioral rhythms in mice with disrupted neuropeptide signaling.
• In both intact and deficient signaling models, SVE reduced SCN neural activity.
• SVE altered GABAergic signaling within the SCN.

Conclusions:

• Regular exercise can enhance SCN clock cell synchrony and improve circadian behavior, even with compromised signaling.
• Exercise modulates SCN neural activity and neurotransmission.
• Exercise shows potential as a non-invasive intervention for blunted or misaligned circadian rhythms in aging and mental illness.