Upregulated expression of N-methyl-D-aspartate receptor 1 and nitric oxide synthase during form-deprivation myopia in guinea pigs.

This study aimed to investigate the expression of N-methyl-D-aspartate receptor 1 (NMDAR1) and neuronal constitutive nitric oxide synthase (ncNOS) during form-deprivation myopia (FDM). FDM models were established in guinea pigs with facemasks. NMDAR1 expression in the retina was detected by immunohistochemistry and Western blot analysis. ncNOS mRNA expression was examined by in situ hybridization. cGMP content was measured by radioimmunoassay. In control group, NMDAR1 and ncNOS were expressed in binocular retinas, and there was no significant difference in NMDAR1 and ncNOS expression and cGMP content between the two eyes. However, NMDAR1 and ncNOS expression and cGMP content in the retina of FDM eyes were significantly higher than that of contralateral untreated eyes. Furthermore, ncNOS mRNA level and cGMP content was highly correlated. In conclusion, FDM upregulates the expression of NMDAR1 and ncNOS and increases cGMP content in the retina. NMDAR1/NO-cGMP pathway may contribute to abnormal visual signals during myopic progression.