Differential influence of morphine sensitization on accumbens shell and core dopamine responses to morphine- and food-conditioned stimuli.

Rationale: Sensitization of the incentive and dopamine (DA) stimulant properties of drug-conditioned stimuli (CSs) by repeated exposure to drugs of abuse has been assigned an important role in the genesis of drug addiction.

Objective: To test in rats if morphine-induced sensitization potentiates incentive and DA-releasing properties in the nucleus accumbens (NAc) shell and core elicited by presentation of a morphine-conditioned stimulus(CS) and if this property generalizes to a non-drug-(palatable food, Fonzies)-CS.

Methods: Controls and rats previously sensitized by morphine were trained via three daily sessions consisting of a 10-min presentation of CS (Fonzies filled box, FB) followed by s.

Reciprocal responsiveness of nucleus accumbens shell and core dopamine to food- and drug-conditioned stimuli.

Rationale: Drugs of abuse and palatable food share the ability to stimulate dopamine (DA) transmission in the nucleus accumbens shell. However, while the stimulation of shell DA by food undergoes habituation, that by drugs of abuse does not.

Objective: This study aims to directly compare the changes of extracellular DA, by microdialysis, in shell and core and prefrontal cortex (PFCX) in response to food- and drug-conditioned stimuli (CSs).