ATP-gated nonselective transmembrane cation channel permeable to potassium, sodium and with relatively high calcium permeability (PubMed:10440098, PubMed:15056721, PubMed:20699225, PubMed:8834001, PubMed:8961184). Furthermore, CTP functions as a weak affinity agonist for P2RX1 (PubMed:14699168). Plays a role a role in urogenital, immune and cardiovascular function (By similarity). Specifically, plays an important role in neurogenic contraction of smooth muscle of the vas deferens, and therefore is essential for normal male reproductive function (By similarity). In addition, contributes to smooth muscle contractions of the urinary bladder (By similarity). On platelets, contributes to platelet activation and aggregation and thereby, also to thrombosis (By similarity). On neutrophils, it is involved in chemotaxis and in mitigating the activation of circulating cells (PubMed:19635923). {ECO:0000250|UniProtKB:P51576, ECO:0000269|PubMed:10440098, ECO:0000269|PubMed:14699168, ECO:0000269|PubMed:15056721, ECO:0000269|PubMed:19635923, ECO:0000269|PubMed:20699225, ECO:0000269|PubMed:8834001, ECO:0000269|PubMed:8961184}. This is the function of Ensembl gene identifier ENSG00000108405 (P2RX1, purinergic receptor P2X 1).