A recent study was able to identify neurons that drive and quench salt cravings in the brains of mice. The findings have a potential of regulating sodium cravings in humans. The paper carrying this research appeared online ahead of publication in the journal Nature.
Consuming more salt is often linked to cardiovascular and cognitive disorders. Sodium is found in table salt and plays an extremely important role in various body functions, such as cardiovascular activity, fluid balance, and nerve signaling. In all animal species, the body strictly regulates and maintains sodium levels.
Animals cannot create sodium metabolically on their own, hence the sodium ions have to be in ingested from external food sources. The brain triggers specific appetite signals when the body is low on sodium to drive the consumption of sodium. However, the workings behind these appetite signals are still not understood completely. A team of researchers has now discovered a small population of neurons in the mouse hindbrain that controls the drive to consume sodium.
Graduate student Sangjun Lee lead this team, they used genetic tools to manipulate the activity of these neurons so that they could be stimulated with light.
The team observed that manipulate the activity of these neurons so that they could be stimulated with light.
The researchers then measured the activity of these neurons while mice consumed sodium. Within a few seconds of sodium hitting the animal’s tongue, the activity of sodium-appetite neurons was inhibited. The direct infusion of sodium in their stomachs didn’t suppress the neural activity.
Taken together, the research shows that oral sodium signals, likely mediated by the taste system, are necessary to inhibit the sodium-appetite neurons.
"The desire to eat salt is the body's way of telling you that your body is low on sodium. Once sodium is consumed, it takes some time for the body to fully absorb it,” said Oka.
He added that just the taste of sodium is sufficient to quiet down the activity of the salt-appetite neurons which proves that sensory system like taste is important in regulating the body's functions than simply conveying external information to the brain
A lot of species including humans show that consuming sodium can also drive one’s desire to eat more. In the future, the research team would like to see the applications of this research on how sodium-appetite neurons are modulated over time.
This may bring up avenues to help patients with health issues to consume less sodium in their diets.