High-salt Diet May Disrupt Body Clock

Mice fed a high-salt diet showed abnormal activity in brain region that controls circadian rhythm

Rockville, Md. (October 4, 2021)—Although health experts have long known a high-salt diet (HSD) is harmful to the cardiovascular system, new research finds that it may also disrupt the body’s internal rhythms directly. The research will be presented virtually at the Seventeenth International Conference on Endothelin (ET-17), hosted and organized by the American Physiological Society (APS).

Disruption of the body’s circadian rhythm is associated with increased risk of metabolic syndrome, inflammation, mood disorders, cancer and even premature death. With an estimated 90% of the U.S. population over 2 years old consuming too much salt, these new findings could have widespread implications.

The region of the brain called the suprachiasmatic nucleus (SCN) synchronizes all the clocks throughout our body. The SCN contains a type of receptor called endothelin B receptors. Elsewhere in the body endothelin B receptors play a key role in managing sodium. In fact, medications that block endothelin B receptors are prescribed to manage pulmonary hypertension.

Researchers at the University of Alabama at Birmingham fed mice an HSD and measured their movement throughout the day as well as their neuronal activity. Although their total activity was similar to control mice, HSD mice did not follow sleep-wake patterns established as normal by previous studies.

A hallmark trait of the SCN is to have higher neural activity during the day and less at night. However, HSD mice exhibited significantly elevated neuronal excitability at night as compared to control mice. “Neuronal excitability at night could lead to decline or mistiming of sleep-wake, hormonal and physiological rhythms,” researchers wrote.

Nighttime neural activity abated when the mice were treated with an endothelin B receptor blocker. This abatement demonstrates both that the endothelin system may affect circadian rhythms and that endothelin B receptor medications could have unexpected impacts on the body clocks of people taking them.

NOTE TO JOURNALISTS: The Seventeenth International Conference on Endothelin (ET-17), hosted and organized by APS, will be held October 4–7 on a virtual platform. To schedule an interview with the conference organizers or presenters, contact APS Media Relations or call 301.634.7314. Find more research highlights in the APS Newsroom.

Physiology is a broad area of scientific inquiry that focuses on how molecules, cells, tissues and organs function in health and disease. The American Physiological Society connects a global, multidisciplinary community of more than 10,000 biomedical scientists and educators as part of its mission to advance scientific discovery, understand life and improve health. The Society drives collaboration and spotlights scientific discoveries through its 16 scholarly journals and programming that support researchers and educators in their work.