Feeling Stressed for a Long Time Could be Depressive

Chronic stress can impact our behavior, leading to problems like depression, reduced interest in things that previously pleased us, and even lead to Post-traumatic stress disorder (PTSD) is a known thing. But scientific evidence supporting this fact is lacking. Now scientists have evidence that a group of neurons in a bow-shaped portion of the brain become hyperactive after long-term exposure to stress. When these neurons become super active, all sorts of behavioral problems result and when scientists reduce their activity, it reduces the behaviors. These findings are reported in the journal Molecular Psychiatry.

Scientists looked in the hypothalamus, key to functions like releasing hormones and regulating hunger, thirst, mood, sex drive, and sleep, at a population of neurons called the proopiomelanocortin, or POMC, neurons, in response to 10 days of chronic, unpredictable stress.

Chronic unpredictable stress is widely used to study the impact of stress exposure in animal models, and in this case that included things like restraint, prolonged wet bedding in a tilted cage, and social isolation.

They found that stressors increased the spontaneous firing of these POMC neurons in male and female mice. When they directly activated the neurons, rather than letting stress increase their firing, it also resulted in the apparent inability to feel pleasure, called anhedonia, and behavioral despair, which is essentially depression.

Feel Like Nothing Is Interesting? Try To Avoid Stressors

In humans, indicators of anhedonia might include no longer interacting with good friends and a loss of libido. In mice, their usual love for sugar water wains, and male mice, who normally like to sniff the urine of females when they are in heat, lose some of their interest as well.

Conversely, when the MCG scientists inhibited the neurons’ firing, it reduced these types of stress-induced behavioral changes in both sexes. The results indicate POMC neurons are “both necessary and sufficient” to increase susceptibility to stress.

Excessive activity of neurons is also known to produce seizures and there are antiepileptic drugs given to open potassium channels and decrease that excessive firing. There is even some early clinical evidence that these drugs might also help treat depression and anhedonia.

Advertisement

Researchers have not looked yet, but they want to further explore the role of these channels to better understand how stress affects them in POMC neurons and how best to target the channels if their findings continue to indicate they play a key role in exciting POMC neurons.

Chronic stress affects all body systems, according to the American Psychological Association. Even muscles tense to keep our guard up against injury and pain. Stress can cause shortness of breath, particularly in those with pre-existing respiratory problems like asthma.

Advertisement

Longer term, it can increase the risk of hypertension, heart attack, and stroke, even altering the good bacteria in our gut that helps us digest food.



Source-Eurekalert