When mice don't get enough potassium, their kidney transporter becomes more active and blood pressure rises, but a common blood pressure drug can lower it again.

Even though high potassium lowers a kidney transporter in mice, this doesn't explain the blood pressure changes, suggesting other mechanisms are at play.

Long-term high potassium makes a kidney channel more active, and blocking that channel with a drug lowers blood pressure in mice.

Whether mice get extra potassium for a few days or weeks, a key kidney transporter becomes less active.

When mice eat a lot of salt, adding a moderate amount of potassium lowers their blood pressure, showing that potassium's main benefit might be fighting high blood pressure caused by salt.

When mice eat a lot of potassium for three weeks, their blood pressure goes up mostly at night, no matter how much salt they eat or what form of potassium they consume.