Exposure to Artificial Light at Night Alters Ultradian Rhythms in Endothelial Function

Area of Science:

• Chronobiology
• Physiology
• Cardiovascular Research

Background:

• Circadian clocks regulate physiology and behavior, synchronized by light.
• Artificial light at night (ALAN) disrupts these biological rhythms, impacting health.
• Ultradian rhythms, occurring more frequently than circadian rhythms, are less understood.

Purpose of the Study:

• To investigate the effects of long-term ALAN exposure on cardiovascular function.
• To identify and characterize ultradian rhythms in isolated aortic tissue.
• To determine if ALAN exposure affects these ultradian rhythms.

Main Methods:

• Isolated mouse aortic tissue was studied under controlled light conditions.
• Endothelial-dependent relaxation was measured to assess vascular function.
• Mice were exposed to either dark nights or nights with artificial light at night (ALAN).

Main Results:

• Ultradian rhythms in muscarinic receptor-dependent aortic relaxation were detected in mice with dark nights.
• These ultradian patterns exhibited an antiphase relationship between male and female mice.
• ALAN exposure abolished the ultradian rhythmic patterns in both sexes.

Conclusions:

• ALAN exposure can significantly disrupt physiological ultradian rhythms.
• This disruption affects endothelial-dependent vascular function.
• ALAN poses a potential threat to biological timing and cardiovascular health.