Useful Pain
"Pain neurons" directly protect the intestines from damage
Tatiana Matveeva, "Scientific Russia"
Experiments on mice have shown that "pain neurons" encourage the cells lining the intestinal walls to secrete more mucus, which protects the intestine from damage, reports Harvard Medical School (USA). The results of the study are published in the journal Cell (Yang et al., Nociceptor neurons direct goblet cells via a CGRP-RAMP1 axis to drive mucus production and gut barrier protection).
Our intestines and airways are dotted with goblet-shaped cells. These cells produce a gel-like mucus consisting of proteins and sugars, which acts as a protective coating that protects the surface of organs from damage. A new study has shown that goblet-shaped intestinal cells secrete protective mucus in direct interaction with pain-sensitive neurons in the intestine.
In a number of experiments, scientists observed that mice deprived of pain neurons produced less protective mucus. Also, the composition of the microbiome in the intestine changed in rodents — there was a dysbiosis, an imbalance of beneficial and harmful microbes.
It turned out that pain neurons (marked in gray in the photo) communicate with goblet cells of the intestine (red in the photo) through RAMP1 receptors on the surface of goblet cells. These receptors bind to the chemical CGRP, which is released by neighboring pain neurons when they are stimulated – microbial signals, substances from food, as well as mechanical pressure, chemical irritation or sudden changes in temperature. The researchers found that RAMP1 receptors are found in goblet cells in both mice and humans.
Experiments have also shown that CGRP is released not only in acute inflammation, but also in response to the presence of certain intestinal microbes – to maintain intestinal homeostasis. That is, a feedback loop is formed: microbes send signals to neurons, neurons regulate mucus, and mucus supports the health of intestinal microbes.
Pain receptors also react to certain components of food. When the researchers gave the mice capsaicin, the main ingredient of chili pepper, known for its ability to cause intense, acute pain, the mice's pain neurons quickly activated, causing the goblet cells to secrete copious amounts of protective mucus.
The same mice that had either pain neurons or goblet cell receptors for CGRP removed had a higher risk of developing colitis, a form of inflammation of the intestinal mucosa. This finding may explain why people with intestinal dysbiosis may be more prone to this disease.
When the mice that had no pain neurons were returned with CGRP signaling pain, they began to produce protective mucus better. The treatment protected the mice from colitis even in the absence of pain neurons.
The results of experiments show that pain not only allows you to detect the place of inflammation in the intestine, but also directly protects against inflammation.
Portal "Eternal youth" http://vechnayamolodost.ru