The anxiolytic effects of the 5-HT2A inverse agonist Pimavanserin on a rodent model of anxiet

This study evaluated anxiety-related behavior by male Sprague Dawley rats in the Elevated Plus Maze (EPM). Exploratory behavior and locomotor activity were examined after the administration of either the 5-HT2A inverse agonist Pimavanserin, or a saline control solution. Past research indicates that the EPM is a reliable measure for assessing changes in anxiety behavior in rodents induced by pharmacological manipulations (Corabrez & Bertoglio, 2005). Rats that were administered an intraperitoneal injection of Pimavanserin (3 mg/kg) did not exhibit behaviors (increased open arm time, etc.) that are typically associated with reduced levels of anxiety in comparison to saline injected controls. In support of past research that has found little anxiolytic effect from other 51-1T2A antagonists (Setem, Pinheiro, Motta, Morato, & Cruz, 1999; Rodgers, Perrault, Sanger, & Griebel, 1997), our findings suggest that the 5-HT2A inverse agonist Pimavanserin does not modulate basic anxiety. This suggests that the 5-HT2A receptor induces little modulation of baseline anxiety in the EPM. However, it remains to be explored whether or not Pimavanserin modulates phobia or trauma-induced anxiety.;Keywords: Pimavanserin, Elevated Plus Maze, Anxiety, 5-HT2A.