Relative mRNA expression of NGF and its receptors p75 and TrkA in the retina at 8 days after vessel ligation. NGF mRNA increased in all the experimental groups when compared with the sham-operated group of animals (A) and also in the 2VO-NGF group when compared with 2VO-saline (NGF effect on vascular lesion) (C). The opposite effect was found for the high affinity NGF receptor, TrKA, with a decrease observed in the mRNA level in all the experimental groups compared with the sham-operated group of animals (G). The mRNA level of the low affinity NGF receptor p75 is not significantly altered in the experimental groups studied except in the case of NGF injected sham group of animals (F). Results are presented as mean values ± SEM of experiments performed in duplicate. Statistical analysis was performed by one-way ANOVA and post hoc Tukey's multiple comparison test (#p < 0.05; ###p < 0.001) or Student's t test (*p < 0.05).