Scientists discover surprising brain trigger behind high blood pressure

This area, called the lateral parafacial region, is located in the brainstem, the oldest part of the brain responsible for automatic functions like breathing, digestion, and heart rate.

"The lateral parafacial region is recruited into action causing us to exhale during a laugh, exercise or coughing," says lead researcher Professor Julian Paton, director of Manaaki Manawa, Centre for Heart Research at Waipapa Taumata Rau, University of Auckland.

"These exhalations are what we call 'forced' and driven by our powerful abdominal muscles.

"In contrast, a normal exhalation does not need these muscles to contract, it happens because the lungs are elastic."

How Breathing and Blood Pressure Are Connected

The team found that this brain region is also linked to nerves that constrict blood vessels, which increases blood pressure.

"We've unearthed a new region of the brain that is causing high blood pressure. Yes, the brain is to blame for hypertension!" says Paton.

"We discovered that, in conditions of high blood pressure, the lateral parafacial region is activated and, when our team inactivated this region, blood pressure fell to normal levels."

These findings suggest that certain breathing patterns, particularly those involving strong abdominal muscle use, can contribute to elevated blood pressure. Identifying abdominal breathing in people with hypertension may help pinpoint the cause and guide more targeted treatment.

The study was recently published in the journal Circulation Research.

A Potential New Treatment Target

'Can we target this brainstem region?'

The researchers then explored whether this part of the brain could be treated with medication.

"Targeting the brain with drugs is tricky because they act on the entire brain and not a selected region such as the parafacial nucleus," says Paton.

A key breakthrough came when the team discovered that this region is activated by signals originating outside the brain. These signals come from the carotid bodies, small clusters of cells in the neck near the carotid artery that monitor oxygen levels in the blood.

Because the carotid bodies can be safely targeted with medication, they offer a promising alternative approach.

"Our goal is to target the carotid bodies, and we are importing a new drug that is being repurposed by us to quench carotid body activity and inactivate 'remotely' the lateral parafacial region safely, i.e., without needing to use a drug that penetrates the brain."

This discovery could lead to new ways to treat high blood pressure, especially in people with sleep apnoea, where carotid body activity increases when breathing stops during sleep.