P2RX4 and amyotrophic lateral sclerosis: However, based on the knowledge gained so far, the therapeutic significance of the following strategies might be further evaluated with reference to ALS: (a) quenching the pro-inflammatory function of P2X7, (b) enhancing the anti-inflammatory action of A2A, (c) modulating the cell surface expression of purinergic receptors, and (d) regulating the activities of nucleotide-metabolizing ecto-enzymes, in particular CD39.