The dopamine inhibitor GBR12909 improves attention and compulsive behaviour in female rats

BackgroundStimulants such as methylphenidate are the first-line treatment for attention deficit hyperactivity disorder (ADHD). A principal mechanism of action for these drugs is to reduce dopamine reuptake in the striatum. However, the ensuing risk of abuse with such stimulants means there is an urgent need for new, low-risk therapeutic agents. GBR12909 is a highly selective dopamine reuptake inhibitor, making it an important experimental tool. Indeed, this drug completed Phase II clinical trials for treatment of cocaine abuse. Understanding such drugs has the potential to expand our understanding of the striatal dopamine contribution to impulsivity, attention and compulsive behaviour and will help the development of novel targeted treatments for ADHD without an abuse risk. AimsThe aim of this work was to examine the role of low doses of GBR12909 on attention, impulsivity and compulsive behaviour as measured by 5C-CPT. Oldhams methods was used to determine the presence of a rate-dependent effect. MethodsFemale Lister hooded rats were trained to criterion in the 5C-CPT (>70% accuracy, < 30% omission and < 40% false alarms). Effects of GBR12909 (0.25-1 mg/kg) were investigated on attention, impulsivity and compulsive behaviour under challenging task conditions. ResultsThe two lowest doses of GBR12909 improved selective attention in a rate-dependent manner while the highest dose of GBR 12909 showed a tendency toward improving compulsive behaviour in a baseline-dependent manner. However, GBR 12909 impaired waiting impulsivity in a baseline-dependent manner. ConclusionsGBR12909 has a clearly beneficial effect on attention and compulsive behaviour in the female rat. These findings support further clinical investigation of GBR-type dopamine uptake blockers or GBR analogues to facilitate the discovery of medications for inattentive ADHD, stimulant abuse, compulsive drug seeking behaviour and obsessive-compulsive disorder.