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Involvement of dopamine and opioids in the motivation to eat: influence of palatability, homeostatic state, and behavioral paradigms
- Source :
- Psychopharmacology. 203:475-487
- Publication Year :
- 2008
- Publisher :
- Springer Science and Business Media LLC, 2008.
-
Abstract
- Motivation for food depends on several variables including food palatability, the homeostatic state of the organism, and the nature of the behavior required to obtain the reward. However, few studies to date have tried to evaluate motivation for food considering all these variables at the same time. Since dopamine and opioids have been deeply involved in the regulation of feeding, it is of interest to investigate their role considering all the mentioned variables. In this study, we evaluated the involvement of dopamine and endogenous opioids on food consumption and food motivation using behavioral paradigms that differ in the motor requirement to gain access to the reward, when food palatability and homeostatic state were taken into account. Pellets differentiated on palatability were offered to sated and restricted rats in consummatory tests and in different behavioral paradigms measuring motivational state, but requiring different motor outputs (runway and an operant progressive ratio 3 task). Peripheral injections of naloxone or flupenthixol were administered when these tasks were learned and stable. Naloxone decreased food intake when pellets were palatable, while flupenthixol was without any effect. When considering motivation, naloxone decreased performances in both the runway and progressive ratio tests while flupenthixol was only effective in the progressive ratio test. Impairing the opioid neurotransmission diminishes motivation to obtain food, possibly through a decrease in the perceived palatability of the food reward. The dopaminergic system appears to be more involved in the modulation of motivation to obtain food in a cost/benefit-related manner.
- Subjects :
- Male
Dopamine
Narcotic Antagonists
media_common.quotation_subject
Flupenthixol
Developmental psychology
Eating
Food Preferences
Naloxone
medicine
Animals
Homeostasis
Palatability
Rats, Wistar
Opioid peptide
Endogenous opioid
media_common
Pharmacology
Motivation
digestive, oral, and skin physiology
Dopaminergic
Appetite
Feeding Behavior
Rats
Opioid
Receptors, Opioid
Dopamine Antagonists
Psychology
Neuroscience
medicine.drug
Subjects
Details
- ISSN :
- 14322072 and 00333158
- Volume :
- 203
- Database :
- OpenAIRE
- Journal :
- Psychopharmacology
- Accession number :
- edsair.doi.dedup.....bfd6798c13bb0c031a88f70498e4649e