CRHR1 and Anxiety: CRF via activation of CRF-R1 in the PFC has also been shown to regulate anxiety-related behaviors through the sensitization of serotonin 5-hydroxytryptamine receptor subtype 2 (5-HT2R) signaling (Magalhaes et al., 2010), indicating a possible interaction between CRF and neurotransmitters such as serotonin.