P2RX1 and HIV-1 infection: Several studies indicate that the binding of HIV-1 to host cell increases the intracellular free calcium concentration, suggesting a potential role for membrane receptors or channels at the early stage of viral infection.35, 36, 37, 38, 39 In this context, we initially demonstrated that purinergic receptors, pericellular nucleotide release (such as ATP) and related signaling pathways have a key role in HIV-1 infection by contributing to viral entry into host cells, as well as possibly to other steps of the viral life cycle.