One of the most surprising things that can happen to anyone at any time is vomiting. You may have seen a lot of people puke on Earth, but did you realise that it also happens in space? Gherman Titov, a Soviet astronaut, was the first person to vomit in space in August 1961, And oddly, just before he was going to become the second person to ever orbit Earth, his body demanded him to vomit.
Although scientists only consider vomiting to be a natural method of removing poisonous or indigestible material from our gut, a recent study shows that there is much more to it than that. The brains of mice were recently mapped by a team of scientists from China’s National Institute of Biological Sciences (NIBS) when the mice were experiencing the urge to vomit.
The researchers believe that by better understanding what happens inside the brain during vomiting, they will be able to produce better anti-nausea drugs for cancer patients undergoing chemotherapy.
You can control vomiting by manipulating neurons.
Mice, unlike humans, have long food and air pipelines in comparison to their body size. Furthermore, their body muscles are too weak to sustain the tension caused by puking, therefore mice (and other rodents) can never vomit. They do, however, have the urge to vomit, so they barf or retch.
“Retching’s neurological process is similar to that of vomiting.” “In this experiment, we effectively built a paradigm for investigating toxin-induced retching in mice, with which we can delve into the brain’s defensive reactions to toxins at the molecular & cellular levels,” stated Peng Cao, one of the authors and an assistant investigator at NIBS.
The researchers watched two groups of mice during their research. Members of the first group were exposed to staphylococcal enterotoxin A (SEA), a bacterial toxin that causes various gut-related issues in humans, including enteritis, bowel illness, and diarrhoea, in an effort to cause retching. The second group of mice subjected to saline water.
The bodies of SEA-exposed mice reacted in the same way that a dog’s body reacts when it vomits. Their body muscles & diaphragm contracted at the same time, and they opened their mouths far wider than the mice that-had saline water. Several neurotransmitters were also activated and released, according to the study.
They found that during gags, the mice’s brains commanded the release of serotonin from enterochromaffin cells in the gut. In the gut there are neural receptors that send signals directly to the brain. The released serotonin also interacts with brain receptors and this interaction leads to the activation of Tac1+DVC neurons (dorsal vagal complex) located in the dorsal vagal region of the mouse brain.
It’s interesting to note that the mice’s retching habit decreased when the Tac1+DVC neurons were deactivated by the researchers.
Why is it important to cancer patients?
They discovered that a cancer patient’s body’s defensive mechanism during chemotherapy also results in behaviours like nausea & vomiting. The lives of cancer patients are made more uncomfortable by these unwelcome side effects. Cao and his team thought that perhaps by inactivating Tac1+DVC neurons, they could also reduce the nausea that develops as a result of chemotherapy.
To test this theory, they exposed mice to a chemotherapy drug called doxorubicin, and unsurprisingly, this experiment resulted in the mice gagging. The researchers then deactivated the Tac+DVC neurons and it worked! They found that after the neurons were deactivated, gag behavior was greatly reduced.
These discoveries also shed insight on why and how some anti-nausea medications that are already on the market successfully blocking serotonin receptors. With the help of this study, we can now better understand the cellular and molecular causes of nausea & vomiting, which can aid in the creation of more effective treatments.
The study is published in the journal Cell.