ADENOSINE A2A RECEPTOR MODULATES SODIUM-INDEPENDENT GLUTAMATE TRANSPORT IN RETINAL CELL CULTURE

The control of glutamate extracellular levels is crucial to prevent neurotoxicity and consequent neuronal death, evidencing the importance of glutamate transporters activity for normal tissue function. In the retina, more than 50% of glutamate transport is Na⁺-independent, most likely occurring through system xCG-, which regulates cystine intracellular and glutamate extracellular concentrations. Once the retina is highly susceptible to excitotoxic events, modulatory mechanisms, such as the adenosinergic system, may be essential to preserve retinal homeostasis. Adenosine has a very prominent neuromodulator role, acting upon glutamatergic release and reuptake, with concentration- and receptor-dependent effects. Therefore, adenosine may represent an important regulatory mechanism of sodium-independent glutamate transport.