Imagine you are exercising outdoors on a hot day.You are sweaty, and the thirst starts to rise.You take out the water bottle and take the first big sip - and your body is immediately filled with a sense of relief and excitement.
"There is a pleasure reaction to it," Patrica Di Lorenzo, an honorary professor of psychology at Binghamton University in New York (USA), told Live Science."When you are really thirsty and you drink water, it tastes very delicious."
But why does drinking water feel so excited when you are thirsty?
We are thirsty when exercising high intensity, because when we sweat, our blood will decrease.Most areas of the brain are separated by the brain barrier, a layer of cells that prevent harmful toxins and pathogens from entering the brain.But some parts of the brain are outside this fence, allowing quickly detecting changes in our blood.When we lose blood volume due to exercise or eat salty food, nerve cells in these brain parts will send signals to activate thirst.
"This fast reaction is very important for survival," said Yuki Oka, a biological professor at the California Institute of Technology (Caltech) in the United States, telling Live Science."If it takes too much time, you may be dehydrated."
The three parts of the brain handle thirst: The subcutaneous organs (SFO), Lamina Terminalis (OVLT) blood vessels and the front market (MNPO).Both SFO and OVLT are outside the bloody barrier.In a 2018 study in the mouse, OKA found that while all three regions had nerve cells that control drinking water when those nerve cells were stimulated, MNPO was in the middle of this process.It transmits thirst from SFO and OVLT to other parts of the brain to promote drinking water.
OKA said it takes about 30 minutes after you swallow water to be absorbed and circulated in the body.But your body starts sending signals to the brain that you are receiving water before you are completely rehydrated.With only the first sip, your brain will release a large amount of dopamine neurotransmitters.Most scientists agree that Dopamine is related to the search for rewards (sensation of refreshing), motion and motivation.It is important that Dopamine promotes animals to use energy into actions that give us rewards or help us survive, including eating and drinking.
If dopamine is released when they perform a specific behavior, "animals tend to repeat that behavior," OKA said."It is a positive signal."
It is still unclear exactly how to drink water to release dopamine.But in a 2019 study published in Neuron magazine (USA), OKA and colleagues discovered that mice thirsty drinking water to release dopamine, while thirsty mice were brought water to water.Directly into the intestine does not.This shows the action of drinking water - not the satisfaction of thirst - releasing neurotransmitters.OKA said this explains why dehydrated patients with intravenous infusion do not feel the same reward as when drinking a cup of cold water.
In a separate process, the action of swallowing water also sends a message to the nerve cells in MNPO that the body is receiving water, according to research.After that, MNPO disabled the thirsty nerve cells in SFO, creating a full feeling.
However, swallowing water is not the only mechanism to prevent thirst.After the water goes down to the intestines, the body detects a decrease in the rate of salt - water in the blood.This leads to an increase in the concentration of a hormone called peptide peptide (VIP).This hormone, instead of the water itself, helps activate nerve cells to signal the brain that the body is full.Many things about how this process is still a mystery;The researchers still do not know where VIP comes from or how to release it.
Source and photo: Live Science