Mouse study shows dopamine released in brain in response to hydration

Credit: Pixabay/CC0 Public Domain

A team of researchers with members from the University of California, San Francisco, and Howard Hughes Medical Institute, also in San Francisco, has found that a certain part of the brain releases dopamine in response to hydration. In their paper published in the journal Nature, the group describes experiments they conducted with thirsty mice.

Prior research has shown that certain parts of the release dopamine, a , as a means of providing pleasurable feedback to other parts of the brain. It is released during sex, for example, or when a person eats something they like, particularly foods that are sweet or fatty. In this new effort, the researchers have found that another part of the brain releases dopamine—this time when the brain is hydrated.

Noting that many animals have learned to determine which foods contain more water, the researchers wondered if there was a feedback mechanism in the brain prompting them to eat those foods that would provide more water, leading to more hydration in their brains. To find out, they turned to mice.

The experiments involved restricting water in and using technology that allowed them to focus on the (VTA) in the brain. In one experiment, thirsty mice were given unlimited access to water for five minutes while the researchers monitored brain waves emanating from the VTA—a means of measuring how much, if any, dopamine was being produced. As expected, dopamine production levels rose as soon as the mice began drinking. But the researchers were then surprised to find that 10 minutes later, the dopamine levels rose again—coinciding with the amount of time it took for the water they had been drinking to reach their brain. The researchers then repeated the experiment but added salt to the water—the second bump in dopamine was much smaller due to the dehydrating impact of the salt.

The researchers then looked to see if the second bump in dopamine production had a lasting impact on the mice. They gave the mice a choice of water bottles colored differently—both were pure water, but when the mice drank from the second bottle, the researchers injected a small amount of salt into their gut. After several , the researchers found the mice began to prefer the water that was not associated with a salt injection. They suggest this indicates that production in the mouse VTA helps the mice to learn which liquid to drink, or which food to eat, to ensure that they get enough water.

More information: James C. R. Grove et al, Dopamine subsystems that track internal states, Nature (2022). DOI: 10.1038/s41586-022-04954-0

Journal information: Nature

© 2022 Science X Network

Citation: Mouse study shows dopamine released in brain in response to hydration (2022, July 20) retrieved 29 September 2023 from
This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.

Explore further

Dopamine found to be an initiator of REM sleep


Feedback to editors