Changes in gene expression of Ntrk2/Pi3k pathway following vital stress in rats with compulsive overeating

Background: Compulsive overeating, also known as paroxysmal overeating, differs from other eating disorders such as bulimia or anorexia nervosa because it is not associated with compensatory behaviors. Vital psychogenic stress has been demonstrated to be a contributing factor to the development of post-traumatic stress disorders. Despite the available data on the involvement of mediator and cell signaling systems in the effects of post-traumatic stress disorders, there has been a paucity of studies investigating changes in the gene expression following vital stress. This phenomenon is particularly evident in the genes of the NTRK2/PI3K signaling pathway, which is induced by Bdnf and is a component of the neurotrophic mechanism.

Aim: To assess the effect of stress on the brain expression of Ntrk2 and Pi3k genes in response to predator presentation.

Methods: The experimental study comprised of 86 male Wistar rats, weighing between 200 and 250 g. A high-carbohydrate diet was made available to the experimental groups for one hour, in addition to the standard food granules. Male Wistar rats that exhibited compulsive overeating received a high-carbohydrate diet (a chocolate spread mix) for one hour every third day. Fifteen minutes prior to feeding, the animal was placed at a 5-cm distance from the food, with visual contact maintained throughout the experiment. After becoming food addicted, the rats were placed in a terrarium with an Indian python, where one of them was consumed by the predator. The animals that remained alive after the death of their fellow were subsequently confined within a terrarium, with a transparent partition separating them from the python.

Results: Polymerase chain reaction demonstrated the hypothalamic gene expression in the Ntrk2/Pi3k signaling pathway. The gene expression levels were elevated in the group of rats following the predator presentation. However, the Ntrk2 expression demonstrated a 1.5-fold decrease following stress exposure. However, the Ntrk2 and Pi3k expression was found to be reduced by 2.8 and 5 times, respectively, as compared to non-stressed rats that received chocolate. The Pi3k expression increased twofold in stressed rats that did not receive chocolate.

Conclusion: The findings from this study offer new insights into the synthesis of pharmacological peptides, which have the potential to address food addiction caused by psychogenic stresses during ontogenesis.