2024-03-24 23:47:31
Research has discovered that a nerve pathway between the heart and brain can cause fainting. (Shutterstock)
[The Epoch Times, March 25, 2024](Reported by Epoch Times reporter Linda) Scientists have discovered a channel (NPY2R VSN) between the heart and brain of mice, which seems to be related to loss of consciousness (syncope). Part of the answer to a scientific puzzle that has persisted for years. It may lead to better prevention and treatment of cardiovascular disease and fainting.
If you have ever fainted, you may remember that before you fainted, you suddenly felt dizzy and nauseous, or had ringing in your ears, blurred vision, and then fell unconscious. After you woke up, you would ask yourself: What happened?
For years, researchers attributed syncope to a sudden obstruction of blood flow to the brain. But the actual reasons and mechanisms by which this phenomenon occurs remain a mystery.
November 1 last year “natureA study published in the journal Nature describes a heart-brain pathway in mice that can cause fainting when neurons within it are activated.
“This is a first step,” study co-author Vineet Augustine, a neurobiologist at the University of California, San Diego (UCSD), told NBC. “The cause of syncope is not just reduced blood flow, although that does occur. “It plays a role, but there are other brain circuits at play, and it’s not as simple as what the cardiology textbooks say.”
new research methods
To better understand syncope, the team focused on mice, studying a group of neurons in the vagus nerve, which connects the brain to the heart’s digestive system. The vagus nerve contributes to a variety of body functions, including digestion, heart rate, coughing, sneezing, swallowing, and vomiting. It also helps the body terminate its fight-or-flight stress response.
The researchers identified specific neurons in the channel, which connects the heart’s lower chambers to the brainstem. These neurons have a receptor associated with vasoconstriction.
The researchers used ultrasound imaging and optogenetics, a method of controlling neurons using light, to trigger the NPY2R VSN to see what happens. Within seconds, the previously roaming rat lost consciousness, and a few seconds later regained consciousness and began walking once more.
“Honestly, we’re not 100 percent sure what’s going to happen,” Jonathan Lovelace, a neuroscientist at the University of California, San Diego and co-author of the paper, told “scienceScience magazine, “But I don’t think knocking him out is the first possible outcome.”
Upon activation of the NPY2R VSN, mice also exhibited symptoms typical of human syncope, including rapid pupil dilation, eye movements, decreased blood pressure, decreased heart rate, depressed respiratory rate, and reduced blood flow to the brain. More tests showed that when the researchers removed the NPY2R VSN, the syncope disappeared, according to a statement from UC San Diego.
Additionally, the team found that when mice passed out, neuronal activity decreased in all areas of the brain except the periventricular region, a region of the hypothalamus. When the researchers blocked activity in this area, the mice took longer to regain consciousness. And when this area was stimulated, the mice woke up. According to Nature News, this suggests that syncope and recovery are regulated to some extent by neural networks including the NPY2R VSN and periventricular regions.
Future applications are expected
“From a clinical perspective, this is all very exciting,” said Richard Sutton, a clinical cardiologist at Imperial College London who was not involved in the study. This work “doesn’t answer every question right away, but I think with further study it might answer almost all of them.”
By further understanding the human heart, the study may help treat cardiovascular disease, the leading cause of death worldwide, the study authors wrote in the paper.
Additionally, the research might inspire new ways to prevent syncope, which occurs in regarding 40 percent of people at some point in their lives. To prevent and treat syncope, doctors might replace or remove genes related to the vagus nerve, NBC News reported.
“You can expect some treatments to be on the horizon,” Zachary Goldberger, a cardiologist at the University of Wisconsin-Madison School of Medicine and Public Health who was not involved in the study, told Natural News. ◇
Editor in charge: Lin Yan#
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