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Updated: May 11, 2026
Simultaneous Detection of c-Fos Activation from Mesolimbic and Mesocortical Dopamine Reward Sites Following Naive Sugar and Fat Ingestion in Rats
Published on: August 24, 2016
Dopamine on D2-like receptors "reboosts" dopamine D1-like receptor-mediated behavioural activation in rats licking
Adriana Galistu1, Paolo S D'Aquila
1Dipartimento di Scienze Biomediche, Università di Sassari, Viale San Pietro 43/B, 07100, Sassari, Italy.
Rationale:
We recently suggested that dopamine on D1-like receptors is involved in the activation of goal-directed responses and the level of response activation is "reboosted" on the basis of an evaluation process involving D2-like receptors assessing "response efficacy". A main piece of evidence in support of this hypothesis was the observation of an "extinction mimicry" effect in the time course of licking bursts after dopamine D2-like receptor blockade in rats licking for sucrose.
Objectives:
The aim of this study was to determine whether the pattern of licking observed with sucrose as a reward could be reproduced in rats licking for a different reward (0.9% NaCl).
Materials And Methods:
We investigated the effects of the dopamine D1-like receptor antagonist SCH 23390 (0.01-0.04 mg/kg) and of the dopamine D2-like receptor antagonist raclopride (0.025-0.25 mg/kg) on the microstructure of licking for a 0.9% NaCl solution in 12-h water-deprived rats in 30-min sessions.
Results:
As previously observed with sucrose as a reward, raclopride reduced the size of licking bursts and produced on the burst number time course an "extinction mimicry" effect, while SCH 23390 reduced licking exclusively by reducing burst number.
Conclusions:
These results are consistent with the proposed hypothesis and provide support to the use of the study of licking microstructure as a valid model not only for the investigation of the mechanisms governing ingestive behaviour but also for the investigation of the mechanisms underlying behavioural activation and the related evaluation processes.
