Can the gut communicate with the brain

 

The brain in the head and the one in the gut always exchange information. But how do they do this? Neuroscientist DiegoBohórquez tries to find the answer.

 

If you are asked where the body's nervous system is, you might answer "brain" or "spinal cord." But apart from the central nervous system consisting of these two organs, our body also contains the enteric nervous system, with two layers of lining and more than 100 million neurons spanning our gut from the esophagus to the rectum. The enteric nervous system is called the "second brain," and it always comes in contact with the one in our skull. This is why considering food alone can cause your stomach to begin to secretase, or why a speech can cause your feelings to be unstable.

 

Until recently, scientists thought the two systems communicate exclusively through hormones produced by enteroendocrine cells scattered throughout the gut lining. After sensing food or bacteria, the cells release molecular messengers that prompt the nervous system to regulate behavior. But it turns out that this process may be more direct. Interestingly, Diego Beohrquez, a gastrointestinal neuroscientist at Duke University and TED researcher, found that some enteroendocrine cells also make physical contact with the enteric nervous system and form synapses with nerves. This revelation opens the door to rethinking how we affect these signals - and may someday change how we treat obesity, anorexia, irritable bowel syndrome, autism and post-traumatic stress disorder.

 

His friend's gastric bypass surgery also contributed to his curiosity. "A friend is fighting obesity and, as a last resort, he has decided to have a gastric bypass surgery, and he has lost a lot of weight and solved her diabetes problem," he recalls. "But most notably, she's changed her taste, she's been kicked back by the sight of the runny nose, but after the surgery she's craving for it." This change of taste has been seen in some of those who have undergone bariatric surgery Of patients have been confirmed, but scientists are not sure how or Bohórquez said, and why this happens. "This is a new theme, but reconnecting the gut seems to have physically changed how we perceive the taste of food in the brain."

 

Although scientists know that enteroendocrine cells feel nutrients in the intestine, the exact pattern of this happening is bleak. They understand that when stimulated, enteroendocrine cells release hormones that enter the blood stream or activate nearby nerves to affect our diet. "My focus is figuring out how the sensory signals of nutrients translate into electrical signals that change behavior," Bohórquez said. He and his colleagues started a careful study of enteroendocrine cells using 3D electron microscopy. Imaging it this way reveals an entirely new structure that was never seen before. "It turns out that enteroendocrine cells have not only microvilli or tiny protrusions that are exposed to the intestine, but they also have a foot extension, which we call neurofelt," Bohórquez said. "Enteroendocrine cells have similar physical properties to neurons, so we wondered if they might also be attached to neurons."

 

Keep track of the secrets of synaptic connections: a special type of rabies. The key to illuminating the process is inserting a small amount of modified fluorescent rabies virus into the colon of mice. "Rabies, a virus that infects neurons and spreads through synaptic connections, is useful for tracking neural circuits when used in a modified form that allows only one neuron to beat once," explained Bohórquez. Seven days after this procedure, the gut endocrine cells in the mouse colon are green, providing evidence that the sensor cells do indeed behave as neurons. Then Bohórquez gave birth to a rat, allowing rabies to catch a jump. When he sends rabies into the colon of this new mouse, enterocytes and the nerves they connect light up, indicating that there is a physical synapse between sensor cells and their nervous system - and no physical connection has ever been seen before.

 

Developing communication between the gut and the brain may one day lead us to new treatments for diseases and conditions. Many diseases - autism, obesity, anorexia, irritable bowel syndrome, inflammatory bowel disease, post-traumatic stress disorder and chronic stress - have a symptom called altered visceral sensation, or gut irritation High sensitivity or low sensitivity. "For example, clinical observations suggest that some children with anorexia may be highly aware of what they had when they were young," Bohórquez said. "Under normal circumstances, there is no detailed spatial and temporal awareness of this process, but these children can feel what is going on there, which triggers anxiety." With this knowledge, scientists can better understand what others are perceived as Merely mental illness.

 

Can our gut endocrine cells smell, taste and touch? Bohórquez said they have the same molecular receptors that can be mechanically, chemically and thermally induced in the nose and mouth. "These mechanisms are just beginning to be researched and are exactly where research is going." He points out that organs outside the gut, including our lungs, prostate and vagina, have sensor cells that resemble enteroendocrine cells. "Future exploration will continue to reveal how the brain perceives signals from these organs and how they affect our feelings," he said.