You might not realize it, but every time you stand up, your body is working behind the scenes to stop you from fainting.
Due to the sudden drop in blood pressure, special neurons called baroreceptors swing into action to compensate – and scientists just figured out more about how they operate.
Considering the details of baroreceptors have puzzled researchers for nearly 100 years, this is quite an achievement.
Now the team from the Scripps Research Institute has pinpointed two proteins that sense blood pressure and control the baroreceptor response.
Once that happens, your body is told to increase its heart rate, pushing more blood to your brain to compensate, and ensuring you don't collapse just because you fancied getting up from the sofa to pick out something from the fridge.
"Our motivation for this study was rooted in basic science, yet these findings could have major translational implications by improving our understanding of human health," says microbiologist Ardem Patapoutian from the the Scripps Research Institute.
The two proteins in question, PIEZO1 and PIEZO2, were first discovered several years ago by Patapoutian. Since then, studies have shown these two proteins do a lot of useful work around the body.
Now we know that includes playing a part in the baroreceptor reflex (baroreflex).
In experiments with mice, those that were denied PIEZO proteins showed greater risk of hypertension and more variability in their blood pressure.
When the PIEZO proteins were introduced in mice using optogenetics, however, blood pressure and heart rate were increased, suggesting the baroreflex kicking into action. It seems that both PIEZO1 and PIEZO2 are needed for the baroreceptors to work.
It's not quite a closed case yet, the researchers note, because some as-yet-undiscovered mechanism could be at work behind the scenes, and these tests were only carried out on mice.
However, it does match what scientists have observed in humans where the baroreflex isn't working like it should.
Now that the functioning of the baroreceptors is becoming clearer, it might lead to better insights into ways to keep our bodies healthy – something blood pressure regulation is a crucial part of.
If your blood pressure gets too low, you can easily feel faint, which is what the baroreflex combats.
Too high, and you run the risk of that stress leading to a heart attack, a stroke, or heart failure – here are some ways, backed by science, to stop that from happening.
Hypertension that has previously been unresponsive to drug treatment could be targeted through the PIEZO proteins, for example.
Further studies might also look at how these proteins are affected by changes in our genetics.
"Knowing the identity of the sensors for blood pressure control gives us an idea of how to develop better therapies to treat patients who suffer from drug-resistant hypertension, or any other problems with blood pressure control," says one of the team, Kara Marshall.
The research has been published in Science.