br Discussion The present study showed

Discussion The present study showed that KPT-9274 receptor the factors of pre-exposure and glutamate drug injections might affect the total latency time. However, the factor of sex did not affect the total latency time. The results indicate that the glutamate system and pre-exposure, but not sex, influence fear conditioning. In the test of pre-exposure and glutamate drug interaction, the total latency time of the saline injection in the pre-exposure group was significantly lower than that of the saline injection in the non-pre-exposure group, indicating that latent inhibition was found. However, glutamate agonist NMDA and antagonist MK-801 did not affect the effect of latent inhibition in the pre-exposure condition. The findings supported the hypothesis that the glutamate system would not affect latent inhibition (Palsson et al., 2005, Tenn et al., 2005, Weiner and Feldon, 1992). Moreover, the sex factor was not involved in the latent inhibition of brain glutamate drug injections. The present data were inconsistent with previous findings (Bethus et al., 2005, Wang et al., 2012, Weiner et al., 1985).