In support, systemic injection of the 5-HT agonist, mCPP, which has a high affinity for 5-HT2B and 5-HT2C receptors, increases BNST c-Fos expression and anxiety-like behavior, and the BNST may be the critical site of action for these effects (Singewald et al., 2003). This evidence concerns the gene FOS and Anxiety.