Nucleus accumbens dopamine and it's role in positively reinforcing aggression

Abstract

Rationale: We studied whether mesocorticolimbic dopamine (DA) in the nucleus accumbens (NAc) mediates the rewarding properties of aggression.Objective: To address this issue, we studied the effect of administrating specific DA receptor antagonists into the NAc on aggression and general movement.Methods: A residentintruder model of aggression was used with male mice. An operant conditioning paradigm was used to establish a baseline rate of nose pokes to contingently access aggression as a positively reinforcing stimulus. We analyzed whether microinfusions into the NAc of SCH‐23390, a D1 like DA receptor antagonist, or sulpiride, a D2 like DA receptor antagonist, altered aggression and/or movement. Open‐field tests were used to further assess the effects of SCH‐23390 and sulpiride on movement.Results: Infusing either SCH‐23390 or sulpiride decreased responding for contingent aggression in a dosedependent fashion without disrupting general movement. Infusing SCH‐23390 or sulpiride did not disrupt movement in the open‐field tests at dosages reducing operant responding in the previous aggression tests.Conclusions: Our results suggest that both D1‐like and D2‐like DA receptors in the ventral striatum may mediate the rewarding properties of aggression as a positively reinforcing stimulus.