Researchers have found that a mouse in pain has a lower desire to eat. A similar brain circuit may also be present in humans.
It may be possible to finally understand the link between chronic discomfort and loss of appetite – at least in mice.
Zhi from the University of Science and Technology of China, Hefei, and colleagues injected mice with bacteria that cause chronic pain. These mice ate less often and for shorter durations compared to control mice who had been injected with saline. Researchers reported in Nature Metabolism that when the first group was given pain medication later, they ate normally.
Researchers analyzed the neurons in the first group of mice while they were experiencing chronic pain. The researchers found significant neuronal signaling in the anterior cingulate cortical region, which is a part of the brain that processes pain in the prefrontal lobe.
Researchers induced chronic pain in another mouse group to determine if that signaling is related to appetite loss. These mice ate less. The researchers then administered a substance that inhibits neuronal signals in the anterior cortex, and the appetite of the mice improved.
The prefrontal cortex does not control appetite. The team wanted to understand better the role of neurons in the anterior cortex in controlling appetite. They injected traceable substances into these neurons.