HTR1A and Anxiety: The activation of the postsynaptic 5-HT1A receptor may express the anti-aversion effect of 5-HT, while activation of the presynaptic 5-HT1A heterogeneous receptor may play an anti-anxiety role by inhibiting the release of glutamate from presynaptic terminals, thereby reducing the signal transduction of the postsynaptic 5-HT2C receptor (Hammack et al., 2012).