Short-term stress impairs memory and learning ability

Experts have long known that severe stress lasting for several weeks or months can disrupt the interaction between the cells of the brain regions responsible for learning and memory. Scientists at the University of California, working under the guidance of Dr. Tallie Z. Baram, for the first time found that short-term stress has a similar effect.

Stress is an integral part of our lives, so the discovery can play an important role in the development of new drugs to prevent the undesirable effects of stress, in addition, it explains the forgetfulness and difficulty in remembering information experienced by some people in stressful situations.

Scientists have identified a previously unknown process leading to the development of harmful effects of stress. They found that acute stress activates the synthesis of corticoliberins – neurohormones that contribute to the production of adrenocorticotropic hormone by neurons of the anterior pituitary gland, which stimulates the synthesis and secretion of hormones of the adrenal cortex, including the main "stress hormone" – cortisol. This activates the body's defense systems, helping it cope with stress, but the action of corticoliberins disrupts the process of memorizing and storing information in the brain.

Learning and memorization occurs due to the functioning of synapses, which are contacts between specialized processes of neurons – dendritic spines.

In experiments on rats and mice, researchers have shown that the release of corticoliberins by the hippocampus – the main center of memory and learning – leads to the rapid destruction of these dendritic spines, which impairs the ability to memorize and store information.

At the same time, blocking interactions between corticoliberins and their receptors eliminates stress-induced damage to the dendritic spikes of hippocampal cells that provide learning and memorization processes.

In addition, scientists were able to reproduce the effects of stress on dendritic spikes using small doses of synthetic corticoliberin, the introduction of which into the culture within a few minutes led to the disappearance of dendritic spikes, which were restored when corticoliberin was eliminated.

The authors also note that drugs blocking corticoliberin receptors are currently under development, which may eventually form the basis of new methods of treating memory disorders and stress-related learning problems.

Portal "Eternal youth" www.vechnayamolodost.ru based on the materials of ScienceDaily

17.03.2008