抑郁,破坏大脑,精神病学 z-bo 2020-11-25 341

　　A new study in biological psychiatry reports that daily rhythm disturbances in the body’s main internal clock can cause depression and anxiety-like behavior in mice. These findings provide insights into the role of the brain’s internal timing system in the development of mood disorders such as bipolar disorder and major depression, which are related to daily (circadian) rhythm disturbances.

　　Dr. Dominic Landgraf, the first author of the University of California, San Diego, said: "Our data show that perturbing the circadian rhythm in completely undisturbed animals is enough to cause behaviors similar to human depression."

　　The inner circadian clock can tell us when to fall asleep, wake up and eat, and synchronize our body processes, thereby helping us to operate throughout the day. Dr. Landgraf added: “It may not be surprising that the destruction of natural synchronization can have a significant impact on our physical and mental health.”

　　However, until now, researchers have not known whether circadian rhythm disturbance is the cause or consequence of mood disorders. In this new study, a team led by David K. Welsh demonstrated for the first time the causal relationship between a functioning biological clock and emotional regulation.

　　Researchers have developed a new genetic mouse model by inhibiting Bmal1, one of the main genes driving the circadian rhythm in the suprachiasmatic nucleus (SCN). The reduced expression of Bmal1 reduces the strength of the clock signal generated by SCN by approximately 80%. For this specific brain area, researchers can focus on the specific role of the SCN circadian rhythm and avoid other changes that confuse the brain area previously studied.

　　In behavioral tests, mice with reduced circadian rhythms lack the motivation to get rid of discomfort compared to control mice. This situation is usually interpreted as despair or despair of the animal. Mice also showed aversion to bright areas, which is considered an indicator of anxiety-like behavior.

　　In addition to behavioral changes, mice with reduced circadian rhythm gained weight compared to normal mice, even though they consumed the same amount of food. This finding suggests that SCN circadian rhythm disorders may lead to metabolic abnormalities observed in many patients with depression.

　　"Importantly, the research results show that even if SCN cannot directly regulate emotions, the changes in the circadian rhythm in SCN are sufficient to cause depression and anxiety-like behavior in mice.