Melanocortin-3 receptors in the limbic system mediate feeding-related motivational responses during weight loss
| Autor: | Clemence Girardet, Heather Macarthur, Andrew A. Butler, Alicia Faruzzi Brantley, Daniel L. Marks, Maria Mavrikaki, Courtney A. Miller, Andras Kern |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
0301 basic medicine
medicine.medical_specialty lcsh:Internal medicine media_common.quotation_subject Dopamine Caloric restriction Appetite Nucleus accumbens Biology 03 medical and health sciences 0302 clinical medicine Limbic system Weight loss Internal medicine medicine Receptor lcsh:RC31-1245 Molecular Biology Melanocortin-3 receptors media_common Motivation Cell Biology Melanocortins 030104 developmental biology medicine.anatomical_structure Endocrinology Knockout mouse Original Article medicine.symptom Melanocortin 030217 neurology & neurosurgery medicine.drug |
| Zdroj: | Molecular Metabolism Molecular Metabolism, Vol 5, Iss 7, Pp 566-579 (2016) |
| ISSN: | 2212-8778 |
| Popis: | Objective Appetitive responses to weight loss are mediated by a nutrient-sensing neural network comprised of melanocortin neurons. The role of neural melanocortin-3 receptors (MC3R) in mediating these responses is enigmatic. Mc3r knockout mice exhibit a paradoxical phenotype of obesity and reduced feeding-related behaviors in situations of nutrient scarcity. Here we examined whether MC3Rs expressed in mesolimbic neurons regulate feeding-related motivational responses. Methods Interactions between Mc3r genotype, cognitive function and energy balance on food self-administration were assessed using operant conditioning with fixed- and progressive ratio (FR1/PR1) settings. Inhibition of Mc3r transcription by a loxP-flanked transcriptional blocker (TB) in C57BL/6JN mice (Mc3rTB/TB) was reversed in mesolimbic neurons using DAT-Cre (DAT-MC3R). Results Caloric restriction (CR) caused 10–15% weight loss and increased motivation to acquire food rewards during training sessions. c-Fos-expression in the nucleus accumbens was increased 1 h following food presentation. While exhibiting weight loss, total food self-administration, enhanced motivation to self-administer food rewards in training sessions held during CR and c-Fos-activation in the nucleus accumbens following re-feeding were all markedly attenuated in Mc3rTB/TB mice. In contrast, cognitive abilities were normal in Mc3rTB/TB mice. Total food self-administration during FR1 sessions was not rescued in DAT-MC3R mice, however enhanced motivational responses to self-administer food rewards in PR1 conditions were restored. The nutrient-partitioning phenotype observed with Mc3r-deficiency was not rescued in DAT-MC3R mice. Conclusions Mesolimbic MC3Rs mediate enhanced motivational responses during CR. However, they are insufficient to restore normal caloric loading when food is presented during CR and do not affect metabolic conditions altering nutrient partitioning. Graphical abstract Highlights • Food-related motivational responses in mice increase with caloric restriction (CR). • Melanocortin-3 receptors (MC3R) are required for food-related motivational responses. • MC3Rs role in food-related motivational responses depends on metabolic condition. • Mesolimbic MC3Rs increase food-related motivational responses during CR. |
| Databáze: | OpenAIRE |
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