Effects of the D2 Receptor Antagonist Raclopride and Agonist Quinpirole on ICSS in C57 Mice (2013)

Undergraduates: Jeff DiBerto, JE Robinson EW Fish, CJ Malanga

Faculty Advisor: Rita Fuchs
Department: Psychology & Neuroscience

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Intracranial self-stimulation (ICSS) is a technique used to measure behavioral response to operant reinforcement. Reinforcement is delivered by electrical stimulation of the medial forebrain bundle (brain stimulation reward (BSR)) following the spinning of a wheel. C57BL/6J (C57) mice were treated with the dopamine D2 receptor antagonist raclopride (0.01 – 0.3 mg/kg, i.p.) and agonist quinpirole (0.1 – 3.0 mg/kg, i.p.) to determine their effects on wheel spinning. Pre- (baseline) and post-treatment BSR threshold (Θ₀) and maximum response rate (MAX) were determined. Raclorpide increased Θ₀ and dose-dependently decreased MAX relative to baseline. Quinpirole had dose- and time-dependent effects on Θ₀, and biphasic effects on MAX. BSR activates the mesocorticolimbic pathway, which is a dopaminergic pathway believed to be involved in reward. This pathway rewards natural reinforcements, such as food, sex, and water, as well as non-natural reinforcements, such as drugs of abuse. ICSS can be used to quantitatively measure the rewarding effects of drugs to determine their mechanisms of action, as well as treatments for their abuse.