HTR5A and Anxiety: Release of serotonin at target neurons activates 5-HT heteroreceptors including the 5-HT1A heteroreceptor which is abundantly expressed in the hippocampus, septum, amygdala, and PFC (Albert et al., 1990) where it mediates serotonin actions on fear, anxiety, stress, and cognitive function (Barnes and Sharp, 1999; Gross and Hen, 2004; Savitz et al., 2009; Meltzer et al., 2012; Donaldson et al., 2013; Garcia-Garcia et al., 2013).