Sodium found to regulate the biological clock of mice

Date:
July 9, 2020
Source:
McGill University
Summary:
A new study shows that increases in the concentrations of blood
sodium can have an influence on the biological clock of mice,
opening new research avenues for potentially treating the negative
effects associated with long distance travel or shift work.



FULL STORY ==========================================================================
A new study from McGill University shows that increases in the
concentrations of blood sodium can have an influence on the biological
clock of mice, opening new research avenues for potentially treating
the negative effects associated with long distance travel or shift work.


==========================================================================
The findings, published in Nature by former McGill PhD student Claire
Gizowski and Charles Bourque, a professor in McGill's Department of
Neurology- Neurosurgery, are the first to show that injecting mice with
a salt solution leads to the activation of neurons associated with the
brain's master circadian clock -- the suprachiasmatic nucleus (SCN).

Our biological clock -- or circadian rhythm -- adapts our body's cells
and organs to changing requirements at different times of day. Prolonged disruption of these rhythms because of jetlag or shift work can lead to
adverse health effects.

Though it is well established that light is the primary factor regulating
our body's biological clock, it was unknown if or how physiological
factors could regulate the SCN.

"Our study is the first to show that the SCN is listening to physiological signals and that such signals can in fact regulate clock time," says
Bourque.

Gizowski and Bourque were able to show that salt-sensitive neurons
found in a specific region of the brain -- the organum vasculosum of
the lamina terminalis -- are capable of activating the brain's master
circadian clock at a time of day when it is normally silent.

"This suggests that there could be ways by which we could speed up the
clock, which could be useful to adapt more quickly to the time change associated with long distance travel, or when our work schedule is
shifted by several hours," explains Gizowski.

The researchers now hope to establish if natural increases in blood
sodium levels -- through eating -- have the same effect and whether or
not these also occur in humans.

"One concern is that although ingestion of small amounts of salt is
pleasant and not dangerous, it can be toxic when consumed in large
amounts," Bourque adds. "Much more work is needed to examine if this
finding is applicable to humans in a safe and practical way."

========================================================================== Story Source: Materials provided by McGill_University. Note: Content
may be edited for style and length.


========================================================================== Journal Reference:
1. Claire Gizowski, Charles W. Bourque. Sodium regulates clock time and
output via an excitatory GABAergic pathway. Nature, 2020; DOI:
10.1038/ s41586-020-2471-x ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/07/200709113542.htm

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