An fMRI Study of SYN115 in Cocaine Dependent Subjects

The dopamine system is critical in modulation of reward and has been implicated in the initiation and maintenance of addiction (Volkow et al 2004). Medications that increase dopamine either directly or indirectly have been shown to have preliminary efficacy at reducing cocaine use in cocaine dependent subjects (Grabowski et al 2004a; Schmitz et al 2008). A novel class of medications that has recently been shown to indirectly modulate dopamine function is adenosine A2A receptor antagonists (Fuxe et al 2007). Based on their effect on dopamine function it has been suggested that these compounds may be efficacious in the treatment of drug addiction (Ferre et al 2007c). Before clinical efficacy studies are undertaken, more basic research on the effects of adenosine A2A antagonists on brain function and behavior are warranted. The aim of this study is to examine the acute effects of a single dose of the selective adenosine A2A antagonist (SYN115, Synosia Therapeutics, Chemical name: 4-Hydroxy-4-methyl-piperidine-1-carboxylic acid-(4-methoxy-7-morpholin-4-yl-benzothiazol-2-yl)-amide) on brain function and behavior in cocaine dependent individuals using functional magnetic resonance imaging (fMRI). To examine the effect of a single dose of SYN115 on brain function and behavior in cocaine dependent subjects.

Hypotheses:

1. SYN115 100 mg will increase brain activation in the dorsolateral prefrontal cortex compared to placebo in cocaine dependent subjects performing a working memory task.
2. SYN115 100 mg will increase brain activation in the ventral striatum compared to placebo in cocaine dependent subjects performing a reversal learning task.
3. SYN115 100 mg will reduce brain activation in the anterior cingulate gyrus and amygdala compared to placebo in cocaine dependent subjects performing a cocaine-word Stroop task.