A team of researchers from Columbia University Medical Center led by Yuki Oka discovered two groups of neurons in the hypothalamus that control the feeling of thirst in mice. In an attempt to understand how the brain controls the desire for water, the team used optogenetic experiments to stimulate specific neurons with a laser. When the ETV-1-positive neurons were stimulated, mice that were not thirsty lapped up water greedily, and when the laser was turned off, they lost interest in water. The neurons elicited only the feeling of thirst and not hunger. An opposite response was observed when researchers activated another set of neurons in the subfornical organ; the mice stopped drinking water even if they were dehydrated. Although the results are promising, the researchers are unclear about whether the same response can be observed in other mammals. Moreover, further research is required to know whether any other regions of brain are associated with the set of neurons the researchers have identified in controlling thirst.
Read more in The Scientist.