High Trait Impulsivity Predicts Food Addiction-Like Behavior in the Rat

Abstract

Impulsivity is a behavioral trait frequently seen not only in drug-addicted individuals but also in individuals who pathologically overeat. However, whether impulsivity predates the development of uncontrollable feeding is unknown. In this study, we hypothesized that a high impulsivity trait precedes and confers vulnerability for food addiction-like behavior. For this purpose, we trained ad libitum-fed male Wistar rats in a differential reinforcement of low rates of responding (DRL) task to select Low- and High-impulsive rats. Then, we allowed Low- and High-impulsive rats to self-administer a highly palatable diet (Palatable group) or a regular chow diet (Chow group) in 1-h daily sessions, under fixed ratio (FR) 1, FR3, FR5, and under a progressive ratio (PR) schedules of reinforcement. In addition, we tested the compulsiveness for food in Low- and High-impulsive rats by measuring the food eaten in the aversive, open compartment of a light/dark conflict test. Finally, we measured the expression of the transcription factor ΔFosB in the shell and the core of the nucleus accumbens, which is a marker for neuroadaptive changes following addictive drug exposure. The data we obtained demonstrate that impulsivity is a trait that predicts the development of food addiction-like behaviors, including: (i) excessive intake, (ii) heightened motivation for food, and (iii) compulsive-like eating, when rats are given access to highly palatable food. In addition, we show that the food addiction phenotype in high impulsive subjects is characterized by an increased expression of the transcription factor ΔFosB in the nucleus accumbens shell. These results reveal that impulsivity confers an increased propensity to develop uncontrollable overeating of palatable food.

The Uncompetitive N-methyl-D-Aspartate Antagonist Memantine Reduces Binge-Like Eating, Food-Seeking Behavior, and Compulsive Eating: Role of the Nucleus Accumbens Shell

“…As previously shown Velazquez-Sanchez et al, 2014), bingeing rats exhibited compulsive-eating behavior, as measured by highly palatable food consumption that was resistant to disruption by aversive conditions. Indeed, rats with a history of daily 1 h access to the highly palatable diet, consumed B173 times more food than Chow control rats, when food was placed in the bright, aversive compartment of a light/dark box.…”

“…Rats were habituated to the home-cage AIN-76A-based diet, hereafter referred to as 'Chow A/I' (5TUM diet formulated as 4-5 g extruded pellets, 65.5% (kcal) carbohydrate, 10.4% fat, 24.1% protein, 330 cal/100 g; TestDiet, Richmond, IN). As previously described (Blasio et al, 2014;Cottone et al, 2012;Velazquez-Sanchez et al, 2014), animals were trained to self-administer food pellets (45-mg precision food pellets (Chow A/I)) and water (100 ml) for 1 h a day, under a fixed-ratio 1 (FR1) schedule of reinforcement in the operant chambers. During instrumental training, food pellets were 45-mg precision pellets, identical in composition to the diet that rats received in the home cage as B5 g extruded pellets, to ensure that food intake during operant sessions was not influenced by any hedonic factors, only by homeostatic needs.…”

“…On the test day, rats were placed into the light compartment, facing both the food cup and the doorway. Under normal, control conditions, eating behavior is typically suppressed when a rat is in the aversive, bright compartment; a significant increase in food intake in spite of the adverse conditions, as compared with control conditions, was operationalized as a construct of 'compulsive-like eating' Dore et al, 2014;Velazquez-Sanchez et al, 2014). The apparatus was cleaned with a water-dampened cloth after each subject.…”

“…The aim of this study was, therefore, to systematically characterize the neuropsychopharmacological effects of memantine using a battery of tasks developed to evaluate different features of maladaptive feeding behavior induced by limiting access to highly palatable food in rats (Blasio et al, 2014;Cottone et al, 2012;Velazquez-Sanchez et al, 2014). In addition, this study was aimed at evaluating which area of the brain mediates the effects of memantine on excessive intake of palatable food.…”

Identifying the Relationship of Food Addiction, Impulsiveness and Loneliness with Different Variables in University Students

“…There is plenty of evidence of impulsivity and addiction has a relationship. Velazquez-Sanchez et al (2014) conducted a study in order to find out if high trait impulsivity predicts addiction-like behavior in rats. High impulsive rats was compared with low impulsive rats and high impulsive rats shown some addiction-like behaviors such as excessive intake of food, increased motivation for food and compulsive-like eating.…”