University of São Paulo Researchers Identify Brainstem Breathing Mechanism Driving Treatment-Resistant Neurogenic Hypertension

University of São Paulo researchers link active exhalation neurons to blood pressure spikes, offering a new target for treatment-resistant hypertension.

By: AXL Media

Published: Mar 17, 2026, 5:29 AM EDT

Source: Information for this report was sourced from São Paulo Research Foundation (FAPESP)

The Neurological Link Between Exhalation and Blood Pressure

A significant portion of the global hypertensive population remains unable to control their blood pressure despite consistent pharmacological intervention. Researchers at the University of São Paulo in Brazil have identified a previously unknown brain mechanism that may explain this resistance, focusing on how the central nervous system coordinates breathing and cardiovascular function. The study demonstrates that specific neurons in the lateral parafacial region of the brainstem, which control active exhalation, also modulate sympathetic activity. When these neurons become overactive, they trigger strong abdominal muscle contractions and simultaneously signal blood vessels to constrict, resulting in persistent spikes in blood pressure known as neurogenic hypertension.

Mapping the Lateral Parafacial Region's Regulatory Role

The lateral parafacial region is located within the medulla oblongata, the lowest portion of the brainstem that serves as the critical junction between the brain and the spinal cord. Using advanced rat models, the investigative team from USP found that this area does more than simply manage the mechanics of breathing out. According to the research published in Circulation Research, these neurons act as a dual-purpose control center that directly impacts the diameter of blood vessels. This discovery marks the first time science has proven that the neurons generating expiratory activity are in direct communication with the sympathetic circuits responsible for maintaining cardiovascular stability.

Advanced Methodologies in Neuronal Manipulation

To confirm the role of these specific brainstem cells, the scientists employed viral transfection and optogenetic techniques to introduce light-sensitive genes into the target neurons. This allowed the researchers to excite or inhibit the lateral parafacial region with extreme precision while recording real-time changes in blood pressure and respiratory activity. When the researchers manually activated these neurons, they observed immediate active exhalation followed by a sharp rise in blood pressure. Conversely, using pharmacogenetic modulation to quiet these same cells effectively eliminated the sympathetic excitation and returned the blood pressure of hypertensive subjects to normal, healthy levels.