KLK8 and Anxiety: Previous studies on animals in restricted conditions have demonstrated that neuropsin is involved in the physiological regulation of hippocampal and amygdaloid plasticity in exploring behavior (Tamura et al., 2006), the induction of hippocampal E-LTP in vivo (Tamura et al., 2006), and anxiety (Horii et al., 2008; Attwood et al., 2011).