The main characteristic of clinical depression is anhedonia, a lack of pleasure in things and activities that were previously beneficial. A study of new mice has revealed important biological factors that contribute to this disease.
The World Health Organization (WHO) states that more than 300 million people of all ages live with depression throughout the world. In addition, according to the WHO, this disease is the “main cause of disability” in the world.
According to the American Anxiety and Depression Association, more than 16.1 million adults have been officially diagnosed with major depression in the United States.
Living with depression can seriously affect a person’s quality of life. This is partly because the main features of depression are anhedonia – the inability to enjoy pleasant experiences, such as: Good food, hobbies or sexual relations.
Approved and approved medicines are available to treat symptoms of depression. The most common are selective serotonin reuptake inhibitors or SSRIs.
However, it might take some time for the SSRI to take effect, and many people with depression cannot see improvement after taking this antidepressant.
Now, a research team from the Department of Physiology at the Faculty of Medicine at the University of Malaga in Spain has identified a new mechanism that seems to make a significant contribution to anhedonia.
The results of this study, conducted by researchers in mice, appeared in the Journal of Psychopharmacology. The authors believe that their findings in the future could lead to new therapies for depression.
Potential for “endless therapeutic strategies”
In the study, scientists have focused on a role called neuronal signaling molecules (neuropeptides) called galanin in emotional regulation.
According to previous animal studies, the team found that galanin contributes to the mechanism of anxiety and the mechanism that causes depression.
For the new study, the researchers wanted to find out whether galanin also plays a role in facilitating anhedonia. In particular, they focus on specific galanin fragments: GAL (1-15).
“We experimentally tested how animals change their response to stimuli of high-intensity appetite such as saccharin or sexual attraction after galanin fragments,” said co-author Carmelo Milon.
The team found that administration of GAL (1-15) at 3 nanomolar concentrations produced strong anhedonia behavior and symptoms. For example, they no longer want to pair or appreciate saccharine which they usually respond well to.
The researchers identified the relationship between these changes and changes in the brain system responsible for the release of dopamine, hormones, and neurotransmitters, which are key components of the brain’s response. This “brain program” encourages people to engage in behaviors that improve survival such as diet and sex.
GAL (1-15) seems to reduce the rat reward scheme activity, making these animals less responsive to ordinary food and promising mating.
Although this may be a relatively small finding, researchers believe that having a good understanding of the function of galanin in the brain can not only lead to new therapies for depression but also for addictive disorders. A wrong gift scheme also identifies this condition.