Extracellular ATP-activated non-selective cation channel (PubMed:10440098, PubMed:27626375, PubMed:29674445, PubMed:31232692). Plays particularly important role in sensory neurons where its activation is critical for gustatory, nociceptive responses, visceral reflexes and sensory hypersensitization (By similarity). {ECO:0000250|UniProtKB:Q3UR32, ECO:0000269|PubMed:10440098, ECO:0000269|PubMed:27626375, ECO:0000269|PubMed:29674445, ECO:0000269|PubMed:31232692}. This is the function of P2RX3 (purinergic receptor P2X 3, Ensembl gene identifier ENSG00000109991).