Salt-Dependent Hypertension May Reduce Blood Flow to the Brain

Investigators from Georgia State University analyzed the neuron activity and found that salt consumption can play a role in blood flow to the brain, study results show.

When neurons are activated, it typically produces a rapid increase of blood flow to that area, but studies have been limited to superficial areas of the brain, such as the cerebral cortex, and examined how blood flow changes in response to sensory stimuli from the environment.

Investigators focused on the hypothalamus, a deep brain region involved in critical body functions, such as body temperature regulation, drinking, eating, and reproduction, to see if deeper regions of the brain can respond to stimuli created by the body.

"We chose salt because the body needs to control sodium levels very precisely. We even have specific cells that detect how much salt is in your blood," Javier Stern, MD, PhD, professor of neuroscience at Georgia State and director of the university's center for neuroinflammation and cardiometabolic diseases, said in a statement. "When you ingest salty food, the brain senses it and activates a series of compensatory mechanisms to bring sodium levels back down.”

Investigators found that the blood flow decreased as the neurons became activated in the hypothalamus, which is the opposite of how the cortex response to sensory stimuli, Stern said, adding that salt triggers a decrease in blood flow that produces hypoxia, which is a mechanism that investigators think strengthens the neurons’ ability to respond to the sustained salt simulation.

They call this “inverse neurovascular coupling.”

This could cause tissue damage in the brain and raises questions about how hypertension, which is triggered by salt, could affect the brain.

Investigators plan to study this process in animal models to determine if it contributes to the pathology of salt-dependent hypertension. They also hope to study other brain regions and diseases with this approach.

The findings were published in Cell Reports.

Reference

Surprising findings on how salt affects blood flow in the brain. News release. November 11, 2021. Accessed November 24, 2021. https://www.sciencedaily.com/releases/2021/11/211111154256.htm