High multivitamin intake during pregnancy leads to dopamine dysregulation in the nucleus accumbens of Wistar rat dams post‐weaning (47.6)

Abstract

Diet‐induced obesity is known to alter dopamine neurochemistry within central reward circuitry essential for coding the rewarding properties of palatable foods. Our objective was to investigate whether high multivitamin (10‐fold, HV) intake during pregnancy alone, which increases post‐weaning (PW) weight gain in Wistar rat dams, affects their dopamine (DA) metabolism and related gene expression in the nucleus accumbens (NAc) when exposed to an obesogenic environment. Pregnant Wistar rats were fed an AIN‐93G diet with either the recommended vitamin (1‐fold, RV) or HV mix (n=15/group). During lactation, dams were fed a RV diet until weaning and then a high fat (RV with 60% fat) diet for 16 weeks. Dams fed the HV diet gained 30% (p<0.05) more weight after weaning than RV dams. Although differences in food intake were not detected, HV dams had a 10% (p<0.05) reduced preference for sucrose when exposed to a two‐bottle preference test (4% sucrose vs. water) at 12 weeks PW suggesting a state of reward hypofunction. Total DA, DA receptor 1a/2, catechol‐O‐methyl transferase and monoamine‐oxidase A mRNA expression in the NAc was unaffected by diets. However, turnover rate of homovanillic acid, but not di‐hydroxypheneylactic acid, was significantly lower in HV dams (p<0.05). In conclusion, HV diet during pregnancy in Wistar rat dams induces DA dysregulation in the NAc later in life and is consistent with PW weight gain.Grant Funding Source: Supported by Canadian Institutes of Health Research, Institue of Nutrition, Metabolism and Diabetes