Expression of nitric oxide synthase in the retina of monocular deprivation amblyopia rats.

OBJECTIVE: Amblyopia or lazy eye is a common visual problem affecting children that cannot correct with lenses. Nitric oxide synthase (NOS) is a critical enzyme that regulates the activity of nitric oxide (NO), a key signaling molecule with multiple roles in many tissues. Among its many activities, NOS has been proposed to be required for normal eye development and altered NOS expression can lead to perturbations in eye development and vision.

MATERIALS AND METHODS: To examine the potential role of neuronal NOS (nNOS) in vision loss, we generated a model of monocular deprivation amblyopia in rats. After suturing one eye, we examined several parameters of neural activity and nNOS expression in the retina 7, 14 and 28 days later.

RESULTS: We found the rapid and progressive loss of neural activity in the retina of sutured eyes compared to non-treated and control eyes. The sutured eyes also showed decreased expression of nNOS at the protein and mRNA levels, indicating a strong correlation between nNOS expression and retina activity.

CONCLUSIONS: These data suggest a potential role for nNOS activity in vision loss, opening potential avenues for therapeutic intervention.