In times of constant and chronic stress, many people turn to their coffee cups for comfort. Surprisingly, this may be a wise choice as caffeine, or increased caffeine consumption, appears to reduce some of the negative side effects of chronic stress. These include significant discomforts such as depression and memory loss. Scientists have recently conducted a study published in the Proceedings of the National Academy of Sciences (PNAS) that delves deeply into the effects of caffeine on the brain and identifies a protein that could be a potential treatment target against the symptoms of long-term stress.
Chronic and unpredictable stress directly affects the neural circuits in the hippocampus, leaving its mark. It lowers mood, reduces memory performance, and significantly increases susceptibility to depression. The scientists involved in the study observed the effects directly on laboratory mice. The animals were subjected to long periods of chronic and unpredictable stress: shaking of cages, sounds of predators, damp sawdust, relocation to empty cages, and sudden reversal of sleep cycles. Just like humans exposed to chronic stress, the symptoms in the mice were quickly noticeable. They lost weight, and their memory suffered significantly. The mice appeared quickly lost and helpless and no longer responded to stimuli, a sure sign of incipient depression.
However, when caffeine was mixed into their drinking water, the mice tolerated stress much better than usual. The depressive symptoms were weaker, and the memory performance of the animals, measured by tasks in mazes, was excellent. Caffeine docks onto a specific protein called the adenosine receptor, and that is why the researchers led by Manuella Kaster examined the changes in adenosine A1 and adenosine A2A due to chronic stress. It became clear that the A2A receptor is produced more under stress, triggering a chain reaction that ultimately causes the actual stress symptoms. Caffeine, on the other hand, docks onto this receptor and thus prevents the “stressful” reaction sequence.
In conclusion, caffeine consumption may have some positive effects on chronic stress. However, it also has negative effects on blood pressure and sleep patterns. Therefore, scientists have developed a chemical that works similarly to caffeine but has fewer side effects. This substance blocks only the A2A receptors and is much stronger than caffeine. Further studies will determine whether this substance is suitable for treating stress and its consequences in humans.
