Operant behavior to obtain palatable food modifies neuronal plasticity in the brain reward circuit

• Published in: European neuropsychopharmacology Vol. 23; no. 2; pp. 146 - 159
• Main Authors: Guegan, Thomas, Cutando, Laura, Ayuso, Eduard, Santini, Emanuela, Fisone, Gilberto, Bosch, Fatima, Martinez, Albert, Valjent, Emmanuel, Maldonado, Rafael, Martin, Miquel
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01-02-2013; Elsevier
• Subjects: Adenoviridae; Aliments; Animals; Body weight; Brain; Brain - drug effects; Brain - physiology; Cannabinoid CB1 receptors; Cannabinoid Receptor Antagonists - pharmacology; CB1 cannabinoid receptor; Cervell; Circuits; Conditioning, Operant - drug effects; Conditioning, Operant - physiology; Conducta operant; Cortex (prefrontal); Dendritic spines; Dendritic Spines - ultrastructure; Drug abuse; Feeding behavior; Food; Food intake; Food-seeking; Genetic Vectors; Internal Medicine; Male; Medicin och hälsovetenskap; Medicinska och farmaceutiska grundvetenskaper; Mesocorticolimbic; Mice; Mice, Knockout; Neural Pathways - physiology; Neuronal Plasticity - drug effects; Neuronal Plasticity - physiology; Neurons; Neuroplasticitat; Neurovetenskaper; Nucleus accumbens; Nucleus Accumbens - drug effects; Nucleus Accumbens - physiology; Obesity; Operant conditioning; Palatability; Piperidines - administration & dosage; Piperidines - pharmacology; Plasticity (behavioral); Plasticity (dendritic); Plasticity (neural); Prefrontal Cortex - drug effects; Prefrontal Cortex - physiology; Psychiatry; Pyrazoles - administration & dosage; Pyrazoles - pharmacology; Receptor, Cannabinoid, CB1 - antagonists & inhibitors; Receptor, Cannabinoid, CB1 - genetics; Receptor, Cannabinoid, CB1 - physiology; Reinforcement; Reward; Structural plasticity; Palatability; Structural plasticity; CB 1 cannabinoid receptor; Food-seeking; Mesocorticolimbic; CB1 cannabinoid receptor
• ISSN: 0924-977X; 1873-7862; 1873-7862
• DOI: 10.1016/j.euroneuro.2012.04.004

Abstract Palatability enhances food intake by hedonic mechanisms that prevail over caloric necessities. Different studies have demonstrated the role of endogenous cannabinoids in the mesocorticolimbic system in controlling food hedonic value and consumption. We hypothesize that the endogenous cannabinoid system could also be involved in the development of food-induced behavioral alterations, such as food-seeking and binge-eating, by a mechanism that requires neuroplastic changes in the brain reward pathway. For this purpose, we evaluated the role of the CB1 cannabinoid receptor (CB1 -R) in the behavioral and neuroplastic changes induced by operant training for standard, highly caloric or highly palatable isocaloric food using different genetics, viral and pharmacological approaches. Neuroplasticity was evaluated by measuring changes in dendritic spine density in neurons previously labeled with the dye DiI. Only operant training to obtain highly palatable isocaloric food induced neuroplastic changes in neurons of the nucleus accumbens shell and prefrontal cortex that were associated to changes in food-seeking behavior. These behavioral and neuroplastic modifications induced by highly palatable isocaloric food were dependent on the activity of the CB1 -R. Neuroplastic changes induced by highly palatable isocaloric food are similar to those produced by some drugs of abuse and may be crucial in the alteration of food-seeking behavior leading to overweight and obesity.