Thirdly, it remains to be investigated how much can atrial electrophysiological changes in depression models be linked directly to P2X7R instead of other ion channels such as Cav1.2, Kv4.2, and Kv1.5 given that P2X7R itself is also an ion channel, which needs further exploration. The gene discussed is KCNA5; the disease is major depressive disorder.