Itching is an extremely common sensation in everyday life, and it can suddenly appear on a certain part of the body and make you want to reach out and scratch it. "Today we're going to talk about why you're itching?" This question may seem simple, but it has plagued mankind for a long time.

Charles Darwin, the proposer of the theory of evolution, had a unique point of view, he arguedItching is associated with a sense of humor。 Because when people are tickled, they tend to laugh involuntarily. At the time, this idea attracted a lot of attention. However, for a long time, it was generally believed that itching and pain were the same feeling, and that itching was just a mild pain. This perception is not unfounded, and there are indeed many similarities between itching and pain on a physiological level.

For example, both use the same type of nerve cells to transmit signals, and the areas of the brain that are activated when itch and pain are generated are very similar. Even some people who are born with a loss of pain do not feel the itch. Based on these phenomena, the idea that itching and pain are the same feeling is deeply ingrained in people's minds. But in reality, these perceptions are wrong.

With the deepening of scientific research, people's perception of itching has gradually changed. In 2007, researchers at Washington University in St. Louis conducted a significant experiment. They injected the mice with a drug called Gastrin-releasing peptideAs a result, the mice quickly developed scratching behavior. This phenomenon immediately piqued the researchers' interest, and in order to further explore the intrinsic link between gastrin and itching, they conducted follow-up experiments. The researchers knocked out the gene for the synthesis of gastrin-releasing peptide in the mice, making it impossible for the mice to synthesize the substance on their own. Miraculously, no matter how much the researchers stimulated the genetically modified mice, they no longer scratched. What's more, these mice are able to feel pain normally. The results of this experiment strongly suggest that itching and pain are essentially two completely different sensations that have their own independent paths when it comes to signaling in the nervous system.

This study is of great significance, as it demystifies itching at the cellular and molecular level, allowing people to truly understand the true face of itch for the first time. After knowing how itching is formed, the follow-up research on itching has a clear direction. Scratching may be the most common way for people to relieve itching, I believe many people have had such an experience, especially when the back is itchy to the point that it can't be done, scratching it with "don't ask for help" (a tickle tool) can make people feel extremely happy in an instant. But everyone often encounters the situation of scratching more and more itchy, and scratching more and more, what is going on behind this? In fact, this is mainly the hormone that is playing the trick.

A study in 2013 reveals some of the mysteries. Studies have shown that scratching can cause some mild pain, and when the nociceptors are activated, it inhibits the activity of nerve cells that sense itching, which in turn affects the transmission of itch signals. In this process, the brain mainly receives pain signals, so people can only feel pain, but not itch. However, the story doesn't end there.

In 2014 years, Japanese researchers have made new discoveries. They found that when a person tickles, the brain releases a substance called serotonin. The presence of serotonin relieves the slight pain caused by tickling, and as the pain subsides, the itch sensation regains the upper hand, and people continue to scratch. This cycle repeats itself, relieving itching through pain, and then producing new serotonin, and it falls into a cycle of tickling and itching.

However, serotonin is not only a "side effect" that makes people tickle more and more, it can also make people feel happy and joyful in addition to relieving pain. Therefore, when you tickle, you will get stuck in a cycle of scratching, but you will usually feel good and comfortable, and this is probably the only comforting thing in the whole process.

However, it should be noted that if you can't control the force when tickling, you may scratch the skin if you use too much force. Once the skin is damaged, microorganisms such as bacteria from the outside world can easily invade and cause infection, which will outweigh the losses. And when the itch is difficult to relieve, it's not just a simple itch, it can be a sign from some other disease.

Skin diseases such as eczema, neurodermatitis, and fungal infections can cause unbearable itching on the skin. More severely, diseases of some internal organs, such as liver or kidney disease, may also manifest as itching on the skin. Therefore, when there is an itch that is difficult to relieve, it is necessary to seek medical attention in time, clarify the cause through professional examination, and then prescribe the right medicine, so as to solve the problem fundamentally.

Itching, this seemingly simple feeling, hides such a complex scientific principle behind it. With the continuous progress of scientific research, I believe that in the future, we will have a deeper and more comprehensive understanding of itching, and we can also find better ways to deal with various itching problems.