rP2X2 corresponds to the ATP-gated nonselective cation channel encoded by the Rattus norvegicus P2rx2 gene (RGD:620251). It can be used as a tool to activate neurons and is typically used in combination with a 'caged' form of the ATP ligand, where ATP is combined with a photolabile blocking group, so that activation of neurons is controlled by light (PMID:12540832). For a comparison of rP2X2 with other neuron activation tools, see PMID:26240426.