[Protective action of melatonin in experimental glaucoma in rats]

We explored the melatonin influence on the level of amino acid neurotransmitters of the retina in glaucoma neuropathy in rats. Glaucoma was caused by the prolong systemic introduction of adrenalin. In the study 3 groups were participated: control animals; the model of glaucoma; the model of glaucoma treated with melatonin (M) in the dose 0.1 mg/kg during 1 month. In a vitreous body, as place of retina neuromediator accumulation, free amino acids (AA) were determined with the method of ion-exchange chromatography. It was revealed that in adrenalin-induced glaucoma neuropathy the retina mediator profile was changed, namely, exciting glutamate and aspartate levels were increased and inhibit GABA and glycine levels were decreased, resulting in a rise of excitatory index (EI) by 55%. The disbalance of AA neuromediators to a great extent was normalized by prolonged M introduction. A decrease under M influence of excitatory AA gutamate and aspartate and an increase of inhibitory AA resulted in the decline of EL by 27% when compared to the untreated group. Thus, reduction of excitatory impuls in retina under influence of M can determine its neuroprotective activity in glaucoma neuropathy.