title: Melanocortin 4 Receptor and Dopamine D2 Receptor Expression in Brain Areas Involved in Food Intake.
abstract: BACKGROUND
  The melanocortin 4 receptor (MC4R) is involved in the regulation of homeostatic energy balance by the hypothalamus. Recent reports showed that MC4R can also control the motivation for food in association with a brain reward system, such as dopamine. We investigated the expression levels of MC4R and the dopamine D2 receptor (D2R), which is known to be related to food rewards, in both the hypothalamus and brain regions involved in food rewards.
  
  
  METHODS
  We examined the expression levels of D2R and MC4R by dual immunofluorescence histochemistry in hypothalamic regions and in the bed nucleus of the stria terminalis (BNST), the central amygdala, and the ventral tegmental area of transgenic mice expressing enhanced green fluorescent protein under the control of the D2R gene.
  
  
  RESULTS
  In the hypothalamic area, significant coexpression of MC4R and D2R was observed in the arcuate nucleus. We observed a significant coexpression of D2R and MC4R in the BNST, which has been suggested to be an important site for food reward.
  
  
  CONCLUSIONS
  We suggest that MC4R and D2R function in the hypothalamus for control of energy homeostasis and that within the brain regions related with rewards, such as the BNST, the melanocortin system works synergistically with dopamine for the integration of food motivation in the control of feeding behaviors.
authors.affiliation: Molecular Neurobiology Laboratory, Department of Life Sciences, Korea University College of Life Sciences and Biotechnology, Seoul, Korea.
authors.forename: Ye Ran
authors.initials: YR
authors.lastname: Yoon
authors.affiliation: Molecular Neurobiology Laboratory, Department of Life Sciences, Korea University College of Life Sciences and Biotechnology, Seoul, Korea. jahyunb@korea.ac.kr.
authors.forename: Ja Hyun
authors.initials: JH
authors.lastname: Baik
keywords: Bed nucleus of the stria terminalis; Central amygdala; Feeding behavior; Food reward; Hypothalamus; Obesity