Dopamine D1 receptor gene expression decreases in the nucleus accumbens upon long-term exposure to palatable food and differs depending on diet-induced obesity phenotype in rats.

摘要: The nucleus accumbens (NAcc) mediates feeding reward; its activity reflects tastants' hedonic value. NAcc dopamine guides immediate responses to reward, however, involvement in establishing long-term after a period of exposure palatable foods has not been defined. Furthermore, reward-driven overeating propels weight increase, but the scale gain depends on animals' obesity-prone (OP) or -resistant (OR) phenotype. It is unclear whether response food obesity susceptibility. We investigated effect unrestricted extended access high-fat high-sugar (HFHS) diet expression genes encoding receptors OP and OR rats. examined persistence HFHS diet-induced changes D(1) D(2) gene rats subjected withdrawal (bland chow for 18 days). Effects restricted by pair-feeding were also studied. Using reverse transcriptase PCR (RT-PCR), we found that mRNA was downregulated vs. animals. observed days withdrawal. led downregulation as well levels compared chow-fed controls. A difference mu opioid receptor detected between during conclude diets lasting consequences system, perhaps modifying motivation search reward. fact animals this extends into reward discontinuation phase, implicates propensity overeat and, effect, prone individuals.