Effect of ritanserin and leuprolide alone and combined on marble-burying behavior of mice.

Obsessive-compulsive disorder (OCD) is characterized by absurd, recurrent thoughts (obsessions) followed by certain stereotyped actions (compulsions). OCD can impair all areas of brain functioning and produce devastating effects on patients and their families. Marble-burying behavior of mice is a well-accepted paradigm to screen anti-compulsive activity. The aim of present study was to evaluate the effect of ritanserin and leuprolide per se and in combination on marble-burying behavior of mice. The present study showed that ritanserin (l, 2 and 20 mg kg(-1) i.p.) per se did not show any anti-compulsive effect. Leuprolide (200 and 300 microg kg(-1) s.c.) per se showed anti-compulsive effect, causing statistically significant inhibition of marble-burying behavior of mice. The prior treatment with ritanserin, 5HT(2A/2C) antagonist (20 mg kg(-1) i.p.), has effectively blocked the inhibitory influence of leuprolide (300 microg kg(-1) s.c.) on marble burying behavior of mice, suggesting that leuprolide, a LHRH agonist, also requires serotonin to express its anti-compulsive effect. Further, it also suggested that the effect of leuprolide appears to be mediated through 5HT(2A/2C) receptors.