Scientists have discovered that the lateral parafacial area in the brain causes constriction of blood vessels, which helps explain why some patients continue to have high blood pressure despite medication.
A recently published in Circulation Research identified a little-known brain mechanism which may contribute to hypertension.
Researchers from Brazil and New Zealand discovered that a small region of the brain stem, known as lateral parafacial areaplays a dual role in regulating breathing and blood pressure. Although it is already known that this region controls vigorous exhalations, such as those that occur during exercise or coughing, the study reveals that it can also trigger constriction of blood vesselsleading to increased blood pressure.
The discovery may help explain why about 40% of patients continue to have uncontrolled hypertension, even with the use of medication. Scientists suggest that the brain region may link subtle changes in breathing patterns to increased activity in the body’s “fight or flight” response, responsible for regulating cardiovascular functions.
To investigate this, researchers performed experiments on mice, using genetic techniques to activate and deactivate region-specific neurons. They monitored nervous signals related to breathing, sympathetic nervous system activity and blood pressure levels. When the neurons were activated, the animals showed an increase in blood pressure due to the stimulation of other neural circuits. On the other hand, when the region was deactivated in hypertensive rats, blood pressure levels returned to normal.
The findings also provide insight into the well-established relationship between sleep apnea and hypertension. During sleep apnea, oxygen levels drop and carbon dioxide levels increase, which also activates the same brain region identified in the study. This suggests that nocturnal breathing disorders may indirectly contribute to sustained hypertension.
Despite the promising results, the researchers warn that the study was carried out in animal modelsmeaning more research is needed to confirm whether the same mechanisms operate in humans. However, the implications are significant, especially considering that hypertension affects around a third of the world’s population and is an important risk factor for heart disease, stroke and even dementia.
Encouragingly, the team has already begun exploring possible treatment approaches. Instead of attacking the brain directly, which can be challenging, researchers are focus on the carotid bodieswhich are small sensory structures in the neck that can influence the brain region in question.
