Effects of dopaminergic drugs on delayed reward as a measure of impulsive behavior in rats.

摘要: Rationale: Impulsive individuals exhibit an exaggerated preference for immediate rewards over delayed but larger rewards, perhaps because they value the less. Dopamine (DA) has been postulated to mediate incentive of thus it may also in impulsive individuals. In this paper, we investigate effects DA agonists and antagonists on versus rewards. Objectives: The study had three main objectives: (1) determine D1 D2 type (2) effect indirect agonist d-amphetamine (3) sensitivity adjusting amount (AdjAmt) procedure acute one-day changes delay reward, deprivation level starting amount. Methods: AdjAmt procedure, rats choose between water given immediately (adjusting alternative) a constant 150 µl by 4 s (standard alternative). is adjusted across trials until rat chooses both alternatives with equal frequency (indifference point). final indicator subjective standard alternative. Results: D1/D2 antagonist flupenthixol (25, 50, 100 μg/kg) raclopride (40, 80, 120 μg/kg), decreased indifference points, whereas SCH 23390 (5, 10, 20 did not affect point. All slowed responding. amphetamine (0.5, 1.0 mg/kg) opposite those antagonists, choice latency, increased number completed Decreasing (6, 24, 48 h) no points Increasing reward (2, 4, 8 s) decreasing available choosing alternative (300, 150, 75 µl) Conclusions: results indicate that (decreased impulsivity) receptor (increased impulsivity). was sensitive 1-day magnitude reward.