[Isoform 6]: ATP-gated nonselective transmembrane cation channel permeable to potassium, sodium and calcium (PubMed:12761352). Unlike other P2RX receptors, the P2X5 receptor is also permeable to chloride (PubMed:12761352). May play a supporting role in the inflammatory response (By similarity). {ECO:0000250|UniProtKB:Q91VE2, ECO:0000269|PubMed:12761352}. [Isoform 1]: Non-functional. . This is the function of P2RX5 (purinergic receptor P2X 5, Ensembl gene identifier ENSG00000083454).