Research shows that the same hormone that generates hunger improves memory
We are talking about ghrelin, a small protein that regulates food intake, increased levels of anxiety and, as findings at the National University of Cordoba (UNC) also optimizes memory. This evidence now opens a route to finding drugs able to modify those processes.
Seven years ago it was discovered that the ghrelin, also called “the hunger hormone”, is closely related to the start of food intake, and it was confirmed that before meals high levels of this peptide (small protein)are present. Many scientific studies were conducted on the topic, especially those intended to find the function and the possible role of this substance in the origin and treatment of obesity and anorexia.
By having the certainty that ghrelin modulates hunger, a group of researchers from the School of Chemical Sciences, led by Susana Rubiales, Professor of Human Physiology, Department of Pharmacology of the academic unit, decided to investigate the relationship between food intake , anxiety and memory.
For this reason, subsequent experiments performed consisted of injecting the substance in the central nervous system of laboratory rats and measuring the three processes. What was the outcome? As expected, they found that when they enter the body, both ghrelin increased hunger of the animals as their levels of anxiety.
“The surprise was discovering the improvement of memory,” says project manager and explains that to assess the phenomenon, it was necessary to perform various tests that showed an “evident increase” in withholding information from the past.
Rubiales emphasizes that their work is “basic research” and that they are trying to explain how the central nervous system modulates substance intake, anxiety and memory from models with behavioral experiments in laboratory rats and different biochemical determinations. However, she stresses that, although the research is missing several steps for it to have a theurapeutic utility in humas, thanks to rapid advances in the production of drugs they will soon be able to “stimulate or inhibit the receptors of ghrelin and, somehow, modular behavior”.
In this regard, the scientist says that finding new drugs for the treatment of obesity, anorexia, bulimia and other eating disorders is a priority among the different research areas of the pharmaceutical industry.
Why link food intake with memory?
The habit of eating and drinking is an important space in the daily lives of people. Therefore, there are many opportunities for information related to time spent eating to be processed and then be able to influence decisions about what, when and how much you eat food.
Rubiales so argues the importance of linking the two behaviors, which adds: “We hypothesize that the representation in memory of the information related to meals eaten in the recent past is a factor that influences the consumption retrospectively, so that manipulating the memory of an episode of intake would be obtained on the effect of reducing the subsequent consumption. ”
Meanwhile, according to the professor, the possibility that ghrelin or its antagonists can be used as potential therapeutic agents in some disorders associated with food intake (obesity, anorexia or bulimia), derives from the assumption that these drugs could modify “not only intake but also some of the emotional turmoil that accompany certain diseases.”
The “hunger hormone” in action
Ghrelin is synthesized in the stomach and the central nervous system. In the first case, the route that it follows within the body is simply going via the blood to a structure called the hypothalamus, where the main nerve cells that regulate intake are located. For its part, the central nervous system also releases the substance when there is a feeling of hunger.
Apart from the evidence that this small protein acts at the hypothalamus and modulates the intake, the university scientists found out that ghrelin also operates in other central nervous system structures (amygdala, hippocampus and dorsal raphe nucleus) that are related with intake, anxiety and memory.
“By injecting the drug in these three structures, we saw that in addition to increasing the food intake and anxiety, it also improved memory,” says Rubiales.
Currently, researchers are continuing the project by analyzing the mechanisms that justify why ghrelin produces certain changes in behavior.