Increased Anxiety-Like Behavior in Neuropsin (Kallikrein-Related Peptidase 8) Gene-Deficient Mice

Neuropsin (kallikrein-related peptidase 8) is concentrated in the hippocampus, amygdala, olfactory bulb, and prefrontal cortex. Earlier studies showed that protease deficiency causes a significant impairment of early-phase long-term potentiation in the Schaffer collateral pathway and hippocampus-dependent memory in the Y maze and Morris water maze (Z. Chen et al., 1995; A. Hirata et al., 2001; H. Tamura et al., 2006). In addition to neuropsin's participation in the hippocampal memory, amygdalar and cortical localization of the gene suggests extrahippocampal behavioral function, and the authors therefore examined neuropsin-deficient mice, including tests of sensory motor reflex, open field, light-dark transition, Rota-Rod, elevated plus-maze, hot plate, startle response-prepulse inhibition, Porsolt forced swim, Barnes maze, eight-arm radial maze, and contextual and cued fear conditioning tests. Here, the authors found increased anxiety in neuropsin-deficient mice, suggesting the involvement of this protease in emotional responses.