Psychic trauma causes increased impulsivity in a model of gambling addiction by altering dopamine and serotonin metabolism in the prefrontal cortex

Abstract

Relevance. Gambling addiction (gambling) involves frequent repeated episodes of gambling that dominate to the detriment of social, professional, material and family values. Gambling addiction is often combined with posttraumatic stress disorder (PTSD).
 Objective. To study the effect of predator presentation stress on the manifestations of gambling addiction in an animal model in a test of probability and magnitude of reinforcement in the IOWA Gambling task, and monoamine metabolism in the prefrontal cortex in rats.
 Methods. Rats were trained in a test of probability and magnitude of reinforcement, in the IOWA Gambling task. in a 3-beam maze. Each run in arm 1 of the maze was reinforced with 1 sunflower seed, each second run in arm 2 was reinforced with 2 seeds, and each third run in arm 3 was reinforced with 3 seeds. Correspondingly, half of the runs in arm 2 and 2/3 of the runs in arm 3 were left unreinforced. After training, the animals were placed in a terrarium with a tiger python, where one of them was victimized for its food requirements. On day 14 after predator presentation, dopamine and serotonin metabolism in the prefrontal cortex was determined using high-performance liquid chromatography with electrochemical detection.
 
 Results and Analysis. A decrease in the content of the dopamine metabolite dioxyphenylacetic acid and the ratio of dioxyphenylacetic acid to dopamine content in the prefrontal cortex was shown. A decrease in the content of serotonin, its metabolite 5-hydroxyindoleacetic acid and the ratio of 5-hydroxyindoleacetic acid to serotonin in the prefrontal cortex was also found in rats after exposure to a predator. At the same time, predator presentation induced significant behavioral changes in rats, increasing impulsivity in making choices in a test of probability and magnitude of reinforcement in the IOWA Gambling task. The acute vital stress of predator presentation increased the number of escapes to the third arm of the maze, suggesting that the animals exhibited more risky behavior observed in the situation of choosing reinforcements of different strength and probability.
 Conclusion. The animal model shows that depletion of dopaminergic and serotoninergic systems of the prefrontal cortex underlies pathological gambling addiction and inadequate decision making caused by PTSD.