The researchers have uncovered a direct, molecular-level explanation of how the microbiome conspires with the kidneys and the blood vessels to manipulate the flow of blood.
Bacteria are therefore the only meaningful source of what activates Olfr78 – which, further experiments showed, is involved in the regulation of blood pressure.
Our bodies must maintain a delicate balance with blood pressure, as with electricity surging through a wire, where too much means an explosion and too little means a power outage.
If blood pressure is too low, an organism loses consciousness; if it’s too high, the strain on the heart and blood vessels can be deadly. One of the ways the body exerts this control is with a hormone called renin, which makes blood vessels narrower when the pressure needs to be kept up.
In a paper last year, Pluznick’s first graduate student, Niranjana Natarajan, now a postdoctoral fellow at Harvard University, revealed the role of Gpr41, which she found on the inner walls of blood vessels.
Like Olfr78, Gpr41 is known to respond to acetate and propionate – but it lowers blood pressure rather than raising it.