Reduced phasic dopamine release and slowed dopamine uptake occur in the nucleus accumbens after a diet high in saturated but not unsaturated fat

ABSTRACT

High-fat diets are linked with obesity and changes in dopamine neurotransmission. Mounting evidence shows that saturated fat impacts dopamine neurons and their terminal fields, but little is known about the effect a diet high in unsaturated fat has on the dopamine system. This study sought to determine whether fat type, saturated vs. unsaturated, differentially affected body weight, blood glucose regulation, locomotor behavior, and control of dopamine release and uptake at dopamine neuron terminals in the nucleus accumbens (NAc). C57BL/6 mice were fed a control diet or a nutrient-matched diet high in saturated fat (SF), unsaturated flaxseed oil (Flax) or a blend of the two fats. After 6-weeks, mice from each high-fat diet group gained significantly more weight than Controls, but the group fed Flax gained less weight than the SF group and had fasting blood glucose levels similar to Controls. Ex-vivo fast scan cyclic voltammetry revealed the SF group also had significantly slower synaptic dopamine clearance and a reduced capacity for phasic dopamine release in the nucleus accumbens (NAc), but the Flax and Blend groups resembled Controls. These data show that different types of dietary fat have substantially different effects on metabolic phenotype and influence how dopamine terminals in the NAc regulate dopamine neurotransmission. Our data also suggests that a diet high in unsaturated fat may preserve normal metabolic and behavioral parameters as well as dopamine signaling in the NAc.

KEYWORDS:

• Saturated fat
• unsaturated fat
• dopamine
• voltammetry
• flax
• nucleus accumbens
• obesity
• neurochemistry

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

HHS Research Excellence Grant (SCF) (R15DK119897); National Institute of Diabetes and Digestive and Kidney Diseases.

Notes on contributors

Cherie N. Barnes

Cherie N. Barnes Graduated with her M.S. in Nutrition from UNC Greensboro, and is currently a registered dietitian.

Conner W. Wallace

Conner W. Wallace is currently a Ph.D. candidate in the Nutrition Department at UNC Greensboro.

Brielle S. Jacobowitz

Brielle S. Jacobowitz is currently an Undergraduate student in Nutrition and Dietetics at UNC Greensboro.

Steve C. Fordahl

Steve C. Fordahl has a Ph.D. in Nutrition and is currently an Assistant Professor at UNC Greensboro where he examines how diet alters dopamine neurochemistry. Dr Fordahl completed his postdoctoral work at Wake Forest School of Medicine examining models of addiction under the mentorship of Dr Sara Jones.