Cytokines are protein molecules. Produced by cells of the thymus gland, immune system, spleen, blood. 90% of cytokines are secreted by B and T lymphocytes. Cytokines perform various functions in the human body, but their main task is to ensure interaction between cells. More than 200 cytokines have been discovered so far. According to the mechanism of action, they are divided into:
- pro-inflammatory cytokines (interleukin 1,2, 6, 8, interferon);
- anti-inflammatory cytokines (interleukin 4.10).
Cytokines are essential for the normal development and functioning of the brain. They affect neurotransmitters – serotonin, dopamine, GABA. The introduction of proinflammatory cytokines or the activation of immune cells activate the adaptive capabilities of humans against viruses and bacteria. Promote recovery from traumatic brain injury.
But the constant stimulation of proinflammatory cytokines leads to long-term changes in the level of neurotransmitters , which leads to mental disorders, including depression.
The effect of cytokines on behavior is associated with the activation of inflammatory processes in the brain, which contributes to the imbalance of monoamines, glutamate, neuropeptides, and a decrease in the production of growth factor – a neurotrophic factor in the brain. In addition, pro-inflammatory cytokines are produced during obesity, childhood mental trauma, stress, poor sleep, which also causes depression.