The 5-HT7 receptor influences stereotypic behavior in a model of obsessive-compulsive disorder.

The 5-HT7 receptor has been suggested as a new putative target for the treatment of neuropsychiatric disorders, especially depression. This hypothesis is based on the finding that antidepressant drugs have relatively high affinity for the 5-HT7 receptor, and that inactivation or blockade of the receptor leads to an antidepressant-like profile in behavioral models and sleep parameters. Obsessive-compulsive disorder is also believed to involve the serotonergic system and is treated using antidepressants, thus it is of interest to study the possible role of the 5-HT7 receptor in this disorder. We have evaluated the effect of inactivation or pharmacological blockade of the 5-HT7 receptor in three mouse behavioral models that are believed to mimic some of the stereotypic aspects of obsessive-compulsive disorder. In the most well-established behavioral model, marble burying, both inactivation and blockade of the 5-HT7 receptor reduced stereotypic behavior in that the number of marbles buried decreased. In two newer, less well-characterized models, head dipping and plastic-mesh screen chewing, there was no difference between wild-type mice and mice lacking the 5-HT7 receptor. Taken together the data confirms and expands on previous findings that the 5-HT7 receptor is of importance for behaviors affected by antidepressants, and suggests that the 5-HT7 receptor might be of relevance as a target for the treatment of obsessive-compulsive disorder.