Enhancement of excessive lever-pressing after post-training signal attenuation in rats by repeated administration of the D1 antagonist SCH 23390 or the D2 agonist quinpirole, but not the D1 agonist SKF 38393 or the D2 antagonist haloperidol.

The authors have recently shown that attenuation of an external response feedback leads to excessive lever-pressing that is not associated with attempts to collect reward, and they have suggested that this may be an analogue to "unreasonable" excessive behavior characteristic of obsessive-compulsive disorder. The present study shows that repeated administration of SCH 23390 or quinpirole, but not SKF 38393 or haloperidol, enhances this behavioral pattern. On the basis of data regarding the enduring effects of chronic treatment with dopaminergic agents, these results suggest that overstimulation of striatal D1 receptors underlies enhanced response to signal attenuation. These results may link the hypothesis that obsessions and compulsions result from a deficient response feedback mechanism with findings implicating dopaminergic abnormalities in the production of obsessions and compulsions.