Diet-induced obesity: dopamine transporter function, impulsivity and motivation

Area of Science:

• Neuroscience
• Behavioral Science
• Obesity Research

Background:

• Diet-induced obesity (DIO) is a growing health concern.
• The roles of dopamine transporter (DAT) function, impulsivity, and motivation in DIO are not fully understood.
• Animal models are crucial for investigating the neurobiological underpinnings of obesity.

Purpose of the Study:

• To determine if dopamine transporter (DAT) function, impulsivity, and motivation predict diet-induced obesity (DIO) in a rat model.
• To investigate neurobehavioral alterations associated with DIO.
• To differentiate between causes and consequences of neurobehavioral changes in DIO.

Main Methods:

• A rat model of diet-induced obesity (DIO) was established using an 8-week high-fat (HF) diet.
• Neurobehavioral assessments included striatal D2-receptor density, DAT function and expression, extracellular dopamine levels, impulsivity, and motivation for food reinforcers.
• Predictors of DIO were evaluated before and after HF diet exposure.

Main Results:

• Obesity-prone (OP) rats showed increased body weight, lower D2-receptor density, reduced DAT expression and function, and higher extracellular dopamine compared to obesity-resistant (OR) rats.
• OP rats exhibited higher motivation for food but were less impulsive than OR rats.
• Motivation for high-fat reinforcers predicted DIO development, whereas impulsivity and DAT function did not predict DIO.

Conclusions:

• Motivation for high-fat foods, not impulsive behavior, predicts the development of DIO in this rat model.
• Decreased striatal DAT function is a consequence, not a predictor, of DIO.
• This study provides insights into the neurobehavioral mechanisms underlying obesity and informs future human research.