By now, you’ve probably heard about circadian rhythms, but how they work comes down to a question of sodium and potasium, according to a new study.
High sodium channel activity in the brain’s circadian neurons could be what wakes us up, while high potassium activity could allow us to sleep, according to the US-based research team.
Sodium and potassium channels transfer ions of the two elements from one side of a cell’s membrane to another.
They are found in many kinds of cells but this study applies to the channels found in the brain’s neurons.
So far, this alternating sodium-potassium activity has been demonstrated to control the sleep-wake cycle in both mice and fruit flies, which is encouraging as far as the possibility goes that it works the same way for humans.
“This oscillation mechanism appears to be conserved across several hundred million years of evolution,” says Dr Ravi Allada, a circadian rhythms expert at Northwestern University. “And if it’s in the mouse, it is likely in humans, too.”
With further research the discovery could lead to new solutions in the fight against insomnia caused by jet lag, shift work and other irregularities in daily schedules.
Allada and his colleagues, whose study was published in the journal Cell, believe that eventually it could be possible to reset the internal clock according to an individual’s situation.
Building on observations of a mutant fruit fly that was missing a sodium channel and whose circadian rhythms were off-kilter, Allada worked for 15 years to find the association.
Working with normal fruit flies, the team observed the neurons’ activity levels and found they fired off in the morning due to the high sodium current and were calmer at night while the potassium current was in full swing.
It’s that balance between the two currents that controls circadian rhythms in the insects and animals observed, according to the researchers.
The sodium and potassium currents act like pedals, say the researchers, conveying time information to the brain’s neurons.
“What is amazing is finding the same mechanism for sleep-wake cycle control in an insect and a mammal,” says lead author Matthieu Flourakis of Northwestern. “Mice are nocturnal, and flies are diurnal, or active during the day, but their sleep-wake cycles are controlled in the same way.”
Working with mice, the team studied the suprachiasmic nucleus – the region of the brain made up of 20,000 neurons that controls circadian rhythms – and sure enough, the mechanism was present, according to the study.