AsianScientist (Oct. 23, 2019) – Researchers at Hokkaido University, Japan, have identified the brain mechanism linking chronic pain and depression in rats. Their research, published in the Journal of Neuroscience, could lead to the development of new treatments for chronic pain and depression.
Clinicians have known for a long time that chronic pain often leads to depression. However, the mechanism responsible for this association remained unclear.
In the present study, researchers led by Professor Masabumi Minami at Hokkaido University, Japan, investigated how neuronal pathways were affected by chronic pain in rats. They used an electrophysiological technique to measure the activities of neurons after four weeks of chronic pain.
The researchers found that persistent pain caused changes in the neuronal pathway projecting from the brain region called the bed nucleus of the stria terminalis, to another region, called the ventral tegmental area.
Specifically, they observed enhanced signaling mediated by corticotropin-releasing factor (CRF), which is a neuropeptide known to be involved in negative emotions such as anxiety and fear. They also showed that this enhanced CRF signaling leads to suppression of the brain’s reward system, which leads to decreased pleasure and motivation.
“By clarifying the mechanism by which the brain reward system is continuously suppressed, we found the missing link between chronic pain and depression,” said Minami.
The researchers noted that when they treated rats with a drug that blocked the excessive CRF signals, the activity of dopaminergic neurons, which play an important role in the brain reward system, was increased. This suggests that drugs targeting neuropeptides such as CRF could be developed in order to treat chronic pain and depression in the future.
“These findings could not only lead to improved treatment of the emotional aspect of chronic pain, but also to new therapeutics for depressive disorders,” said Minami.
The article can be found at: Takahashi et al. (2019) Tonic Suppression of the Mesolimbic Dopaminergic System by Enhanced Corticotropin-releasing Factor Signaling Within the Bed Nucleus of the Stria Terminalis in Chronic Pain Model Rats.
Source: Hokkaido University; Photo: Pexels.
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