Expression of NR1 and apoptosis levels in the hippocampal cells of mice treated with MK‑801.

The aim of the present study was to investigate the characteristics of N‑methyl‑D‑aspartate receptor R1 (NR1) expression and apoptosis in the nerve cells of the hippocampus in schizophrenia‑like mice. C57BL/6 mice were randomly allocated to the following groups: i) Blank group; ii) MK‑801 group; iii) MK‑801+NMDA group, according to body weight. The NMDAR antagonist, MK‑801 (0.6 mg/kg/d) was intraperitoneally injected daily for 14 days to induce a schizophrenia‑like phenotype mouse model, and the effect of the NMDA injection via the lateral ventricle was observed. The results demonstrated that the number of NR1 positive cells in the MK‑801 group increased in the CA1 and DG regions, indicating that NMDA may reverse this change. The level of damage decreased in the MK‑801 treated group when compared with the blank group in the CA3 region. The protein expression of NR1 increased however, at the mRNA expression level, NR1 was lower in the MK‑801 treated group when compared to the blank group; NMDA also reversed this change. In addition, early and total apoptosis detected in the hippocampal nerve cells was significantly increased in the MK‑801 group when compared with the blank group, which was reversible following treatment with NMDA. These results indicated that NMDA may regulate the expression of NR1 and suppress apoptosis in hippocampal nerve cells in schizophrenia‑like mice. Thus, NR1 may be a promising therapeutic target for the treatment of schizophrenia.