“There is only one cut of things that are so important for your body that there is a completely innate will to obtain it if you fall into deficiency,” said Knight. “Oxygen, food, water and sodium.”
However, animals as we do not feel the desire for salt as a powerful and controlling power as we do with oxygen, food and water. The sensors report salt levels in the brain; In addition to the OVLT and the SFO, the senses of the heart detect the stretching of earplugs and ventricles. But there is no pang of similar salt when we need it, the way a stomach turns for food or a rough throat shouts for water. Instead, the need to consume salt is mediated by taste and brain rewards. “The taste of salt is bimodal,” said Knight. “He has a good taste at low doses; high doses, he has a disgusting taste, like drinking Seewater.”
Imagine the desire to eat a big bag of potato crust. If the body needs salt, these shavings will cause a wave of dopamine pleasant to flood the brain. If the body does not need salt, this drop of dopamine disappears. “It is roughly learning to strengthen,” said Yuki OkaNeurobiologist at the California Institute of Technology which studies how the body maintains homeostasis. “More dopamine means in repeated behavior.”
Everyone thirsts differently
Scientists supervising in the river collect data, then have the choice to contract to act on their results. Likewise, it is not because the brain measures blood sodium levels.
Take Elena Gratcheva’s terrestrial squirrels. GracevaAs a neurophysiologist of the Yale School of Medicine, studies these rodents, from North American meadows, to understand how specific brain regions control thirst. The terrestrial squirrel of thirteen layers is an ideal model for this, she said, because he hibernates for more than half of the year, without eating or drinking. “They are like monks,” said Graccheva. “They don’t die outside for eight months. They have no water in their underground burrow.” How do they know thirst?
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It’s not that squirrels don’t need water. They do it. Their bodies scream for that. But according to graccheva research, during hibernation, their brain ignores the signals of the body.
In mammals, a drop in blood water levels (which means a simultaneous increase in salt concentration, all things being equal) triggers two coupled processes. The hypothalamus pumps the hormone of the vasopressin, which tells the kidneys to keep the water rather than let it come out like urine, and the SFO launches the thirst for membership to order the animal to drink. However, while the Hibernate earth squirrels, their Vasopressin levels jumpBut the animal still does not drink. “The vasopressin circuit was normal, but the thirsty neurons were regulated downwards,” said Graccheva. “These two ways are decoupled.” The body tries to keep the water it has but does not act to consume more.
The logic of disturbed circuits is extremely powerful. “Even if you wake them up in the middle of hibernation, they don’t drink,” said Graccheva.
The underlying network that Gracheva studies in squirrels is universal in mammals, up to and including humans. But this same neurological logic does not lead to the same behaviors. Humans drink in glass of water when they are thirsty. Cats and rabbits mainly get water from the food they eat. The camels can burn their water fat reserves (which produces carbon dioxide and water), but they also consume gallons and store it in their stomachs when they need it later. Sea otters can drink ocean water and excrete urine which is More salty than the water in which they swim; They are the only marine mammals to do it actively.
The way each animal manages water and salt specializes in its ecosystem, its lifestyle and its selective pressures. The question “What does this mean being the game?” has no answer. We are each thirsty in our own way.
Original story Reprint with the permission of How many magazinean independent editorial publication of Simons Foundation Whose mission is to improve the public participation of science by covering the developments of research and the trends of mathematics and physical sciences and life.
