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Researchers Identify Neurons in the Brain Circuit That Regulates Thirst


Image credit: Tarasyuk Igor / Image ID: 146471507 / Shutterstock

To stay alive, it is necessary for people to satisfy their aspiration for water. The benefits of drinking water include flushing the waste out of the body, cushioning joints, assisting the delivery of oxygen to cells, helping digestion, and making the brain act properly. Without water, fundamental physical processes would start to fail, so that people would die in a matter of days.

According to the paper published in the latest edition of Nature, some researchers from Columbia University have discovered two obvious distinct set of neurons in the brain that regulate thirst: one set is involved in triggering the need to drink, and the other give signals to the body at which moment it should stop. The neurons are indentified in the subfornical organ, SFO for short term, of the brain,

In order to examine how such neurons function in the brains of mice, lead author Yuki Oka and his colleagues have applied optogenetics to control specific sets of neurons. As you could get from the name itself, optogenetics is sort of technology combining genetics and optics into one so as to control cell function within the brain by the means of light. By doing so, scientists have inserted the light-activated molecules into specific SFO neurons. When a laser shines light on molecules, nerve impulses would be carried out in the positions of being turned “on” or “off.”

In the new finding, it was found that activation of CAMKII neurons triggered thirst, but VGAT neurons suppressed it. Although Joseph Verbalis of Georgetown University did not participated in the study, he was quite sure that it was a very important research targeted at application of optogenetics for identification of separate cell populations, which obviously served in opposite ways on thirst.


CAMKII neurons are in red, VGAT neurons in green. Credit: Charles Zukar Lab.

Located outside the blood-brain barrier, the SFO is only one of a few neurological structures being exposed to bodily fluids. As Charles Zuker, one of the researchers participating in this study said, these cells could have the chance to sense electrolyte balance in body fluids in a direct way.

In the future, more research like this could be helpful to those people with weakened sense of thirst, for example, the elderly who are always dehydrated. It is said that the ideal position of SFO’ near the blood-brain barrier would make it possible to develop drugs for conditions linked with thirst.

Journal reference: Oka, Yuki, Mingyu Ye, and Charles S. Zuker. “Thirst driving and suppressing signals encoded by distinct neural populations in the brain.” Nature (2015).