Influences On Form-deprived Amblyopia Rat VEP And Rat Retinal Dopamine Level When Administrating Levodopa

Objective: To study the effect of different doses of levodopa on the VEP and retinal dopamine levels of form-deprived amblyopic rats, and to discuss the possible mechanism of amblyopic therapy.Methods: 40 Rats were randomly divided into 4 groups, each contained 10 rats, they were normal control group, amblyopia control group, low dose levodopa administration group (LD,20mg /kg) ,high dose levodopa administration group (LD,80mg / kg) , respectively. Form-deprived amblyopia rats models were established by suturing the eyelids of observed eye for 30 days, then they were measued F-VEP before ( at 45-day age) and after administration( at 75-day age), respectively. The retinal dopamine levels were analysed at 75-day age.Results: The P1 wave latent period of form-deprived eyes in each groups were significantly longer compared with non-deprived eyes after administration (P<0. 05) . The P₁ wave latent periods of form-deprived eyes in both high and low doses levedopa administration groups were significantly shorter than those of amblyopic control group (P<0. 05) before administration. And P₁ latent periods for high dose levedopa administration group were shorter than those of low dose group (P<0. 05), while there was no significant difference been detected on the P₁ wave latent periods of non-deprived eyes among each groups. The contents of retinal dopamine in form-deprived eyes were lower than those of Non-deprived eyes (P<0. 05) . The contents of retinal dopamine of deprived eyes in both low and large doses dopamine administration groups were significantly higher than that of control group after administration, and were rising as the increasing of the doses with a statistical significant differcence(P<0.05), while there were no significant difference on the contents of retinal dopamine in non-deprived eyes comparing before and after administration(P>0.05).Conclusions: Levodopa can significantly enhance the contents of retinal dopamine in deprived eyes of rats models, meanwhile improves the visual conductive function of amblyopic eyes, and thus influences the plastic sensitive period of the development of visual system.