High impulsive choice is accompanied by an increase in dopamine release in rat dorsolateral striatum

• Published in: Behavioural brain research Vol. 405; p. 113199
• Main Authors: Moreno, Macarena, Azocar, Victor, Vergés, Alvaro, Fuentealba, José Antonio
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 07.05.2021
• Subjects: Animals; Behavior, Animal - physiology; Delay Discounting - physiology; Delay discounting task; Dopamine; Dopamine - metabolism; Dorsolateral striatum; Impulsive Behavior - physiology; Impulsive choice; Male; Microdialysis; Neostriatum - metabolism; No-net flux microdialysis; Rats; Rats, Sprague-Dawley; Dorsolateral striatum; No-net flux microdialysis; HI; Dopamine; DA Cext; DDT; DLS; Impulsive choice; LI; Delay discounting task
• ISSN: 0166-4328; 1872-7549
• DOI: 10.1016/j.bbr.2021.113199

•Rats were classified as high impulsive and low impulsive according to the AUC.•High impulsive rats showed an increased DA release in dorsolateral striatum.•A negative correlation was observed between impulsive levels and DA release. Dopamine neurotransmission has been consistently associated with individual differences in impulsive choice. Clinical and preclinical evidence suggests that low striatal dopamine D2 signaling predisposes to engage in impulsive behaviors. Although dopamine D2 signaling controls dopamine (DA) extracellular levels, the relationship between striatal dopamine extracellular levels and impulsive choice remains poorly understood. Using quantitative microdialysis, we investigated whether extracellular DA levels in rat dorsolateral striatum (DLS) correlates with preference for an immediate small reward or for a delayed larger reward. Rats were tested in a delay-discounting task and classified as high impulsive (HI) or low impulsive (LI) according to the area under the discounting curve (AUC). No-net flux microdialysis experiments, assessing basal DA release, DA-uptake, and DA extracellular concentration (DA Cext), were carried out in dorsolateral striatum (DLS) of urethane-anesthetized rats. Rats classified as HI showed a higher DA release compared with LI rats. Differences in DLS DA-uptake and DA Cext were non-significant. Importantly, a significant negative correlation was observed between AUC and DA release, indicating that the lower the AUC, the higher the DLS DA release. This finding shows that DA release is augmented in the DLS of rats classified as HI, suggesting that a hyper-activated nigro-striatal pathway contributes to impulsive choice.