Researchers from Harvard Medical School have found in experiments on mice that pain neurons in the mouse gut regulate the presence of protective mucus under normal conditions and stimulate intestinal cells to secrete more mucus during states of inflammation.
The research by scientists published in the journal Cell states that the intestine and respiratory tract contain bocalytic cells that secrete mucus composed of proteins and sugars. It acts as a protective coating that protects the surface of the organs from damage.
Scientists discovered that the surfaces of the bocalytic cells contain the RAMP1 receptor, which is responsible for the cell’s response to pain neurons, which are activated by dietary and microbial signals, mechanical pressure, chemical irritation or sudden changes in temperature.
These receptors are linked to the chemical substance CGRP, which is released by pain neurons. The researchers found that RAMP1 is also present in human and mouse bocalytic cells, making them sensitive to pain signals.
Mice lacking either pain neurons or CGRP were more susceptible to gut inflammation. When the researchers gave pain-signaling CGRP to animals without pain neurons, they saw rapid improvement in mucus production.
This discovery demonstrates that CGRP is a key initiator of the signaling cascade that leads to the secretion of protective mucus.