Dopamine responsiveness in Nucleus Accumbens Shell and Core and Prefrontal Cortex during operant behavior for sucrose
Year: 2014
Type: dissertation
Abstract: Dopamine is implicated in the responsiveness to rewarding properties of natural and pharmacological stimuli. Conditioned stimuli (CS), linked to rewards such as food or drugs of abuse (uncontidioned stimuli, US), are essential to support the motivated behaviour. The role of mesocortical and mesolimbic DA in response to food CS after instrumental paradigm still remains unclear. \nThe aim of our study was to investigate by microdialysis the impact of instrumental food CSs and US on behaviour and on basal DA in three terminal DA areas: shell and core of nucleus accumbens (NAc) and medial prefrontal cortex (mPFCX), using a food self-administration paradigm. \nRats were trained to acquire sucrose self-administration under a Fixed Ratio 1 (FR 1) or FR5 variable time out schedule of responding. \nAfter training, animals were able to self-administer sucrose pellets and microdialysis coupled with self-administration experiments were performed.. \nThe main finding of our study was that NAc shell DA has been activated not only by the conditioned cues but also by food after the instrumental conditioning. When both stimuli are presented in the same moment the increase of DA is strengthened and prolonged. DA response was obtained in NAc core only during US presentation. mPFCX has been activated by each component of motivated behaviour, except for the response to CS using a FR5 schedule. \nWe can conclude that DA in the NAc shell plays an important role on the acquisition and expression of motivated behaviour in food consumption, whereas NAc core and PFCX are less implicated. \nThis study provides a robust and reproducible model for a parametric study of the relationship between behaviour and DA transmission in the NAc shell and core and in the mPFCX .
Author: Cucca, Flavia
Language: English
Subfield: Cellular and Molecular Neuroscience
Field: Neuroscience
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W587411040